feat(lease): add single-turn Claude promotion trigger

fix(lease): raise lease TTL 300s -> 3600s
MAX_LEASE_TTL_SECONDS (daemon cap+default) and DEFAULT_TTL_SECONDS (lease_promote client) both move to 3600. The 5-minute TTL made gated-by-default sessions unusable (re-promotion mid-task); 1 hour matches a working session. Full test:framework-shell RC=0. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_013SAYFkRhQfhguY7AHfiUC8
2026-08-07 19:31:44 -05:00 · 2026-08-07 16:14:01 -05:00 · 2026-08-07 15:15:25 -05:00 · 2026-08-07 14:50:19 -05:00 · 2026-08-07 14:11:40 -05:00 · 2026-08-07 12:59:51 -05:00
23 changed files with 3892 additions and 97 deletions
@@ -0,0 +1,93 @@
+# W-B — Measure Pi's real tool registry
+
+- **Task / internal ref:** W-B from the lease-remediation orchestrator brief (no matching `docs/TASKS.md` row; workers do not modify that file)
+- **Objective:** identify the exact tool names emitted as `event.toolName` by the installed Pi runtime and compare them with the broker's Pi read-only carve-out.
+- **Scope:** measurement and report only; no broker or runtime source changes. W-C is out of scope.
+- **Budget:** no explicit token cap; constrained to this scratchpad and one local commit.
+- **Installed runtime:** `@earendil-works/pi-coding-agent` / `pi` `0.84.1`.
+
+## Method
+
+I created a throwaway extension at `/tmp/measure-pi-tool-registry.ts` (not in the worktree). On `session_start` it recorded `pi.getAllTools()` and `pi.getActiveTools()`; on every `tool_call` it appended the exact `event.toolName`. I then launched an isolated, ephemeral Pi session with all built-ins explicitly selected:
+
+```text
+PI_OFFLINE=1 pi --mode print --no-session --no-approve \
+  --no-context-files --no-skills --no-prompt-templates --no-extensions \
+  -e /tmp/measure-pi-tool-registry.ts \
+  --tools read,bash,edit,write,grep,find,ls <deterministic probe prompt>
+```
+
+The prompt exercised file read, content search, file search, directory listing, shell execution, file write, and file edit. Pi exited `0`; every selected tool produced one `tool_call`. The write/edit control artifact ended with exact content `after`, proving the mutating calls executed in order.
+
+This runtime observation was cross-checked against the installed distribution's canonical registry at `dist/core/tools/index.js:17`, which declares the same seven names. The gate consumes the measured field directly at `packages/mosaic/framework/runtime/pi/mosaic-extension.ts:368`.
+
+## Exact distinct built-in set
+
+The installed Pi built-in registry is exactly:
+
+```text
+{bash, edit, find, grep, ls, read, write}
+```
+
+| Tool | Runtime registry observation | `tool_call` observation | Installed definition |
+| --- | --- | --- | --- |
+| `read` | `<builtin:read>` | observed once | `dist/core/tools/read.js:138` |
+| `bash` | `<builtin:bash>` | observed once | `dist/core/tools/bash.js:231` |
+| `edit` | `<builtin:edit>` | observed once | `dist/core/tools/edit.js:170` |
+| `write` | `<builtin:write>` | observed once | `dist/core/tools/write.js:138` |
+| `grep` | `<builtin:grep>` | observed once | `dist/core/tools/grep.js:79` |
+| `find` | `<builtin:find>` | observed once | `dist/core/tools/find.js:79` |
+| `ls` | `<builtin:ls>` | observed once | `dist/core/tools/ls.js:61` |
+
+The raw distinct `event.toolName` result was:
+
+```json
+["bash", "edit", "find", "grep", "ls", "read", "write"]
+```
+
+Pi registers all seven, but its default active set is only `read`, `bash`, `edit`, and `write` (`dist/core/sdk.js:132`). The probe explicitly activated all seven so the three search/list tools could be observed at the hook.
+
+## Positive control
+
+The known `read` tool was the control. The method surfaced it twice:
+
+1. `pi.getAllTools()` returned `read` with source path `<builtin:read>`.
+2. Reading `/tmp/pi-registry-probe/seed.txt`, which contained `CONTROL_TOKEN`, produced one hook record with `event.toolName === "read"`.
+
+The control was therefore positive; the seven-name result is measured, not an empty-probe inference.
+
+## Carve-out comparison and collision result
+
+The broker currently declares `{"read", "grep", "find", "ls"}` at `packages/mosaic/framework/tools/lease-broker/daemon.py:54`.
+
+- `read`: real built-in.
+- `grep`: real built-in.
+- `find`: real built-in.
+- `ls`: real built-in.
+
+All four carve-out names are exact, case-sensitive Pi tool names.
+
+The general execution/writing tool names are `bash`, `edit`, and `write`. Their intersection with the carve-out is empty:
+
+```text
+{bash, edit, write} ∩ {read, grep, find, ls} = ∅
+```
+
+Therefore no general shell-exec or file-mutating Pi tool shares a name with a carve-out entry. `grep` and `find` may invoke constrained search helpers internally, but neither exposes an arbitrary command interface; the arbitrary command tool is distinctly named `bash`.
+
+The Mosaic extension separately registers the non-built-in custom tool `mosaic_context_recover` at `packages/mosaic/framework/runtime/pi/mosaic-extension.ts:379`; the broker handles that identity through its dedicated recovery exemption rather than the read-only set (`daemon.py:722`). Unknown or third-party custom tools are not part of Pi's built-in seven-name registry and remain outside the carve-out.
+
+## Verification evidence
+
+- `pi --version` → `0.84.1`.
+- Isolated probe exit → `0`.
+- Runtime `getAllTools()` count → `7`, all with `sourceInfo.source === "builtin"`.
+- Distinct hook names → `bash`, `edit`, `find`, `grep`, `ls`, `read`, `write`.
+- Hook counts → exactly one call for each of the seven names.
+- Mutation artifact after `write` then `edit` → exact content `after`.
+- Installed registry source → `allToolNames = new Set(["read", "bash", "edit", "write", "grep", "find", "ls"])`.
+
+## Risks / limitations
+
+- The probe deliberately disabled all other extensions, so extension-defined third-party tools were excluded from the built-in registry measurement. The production gate still receives those names and treats names outside the broker carve-out as mutating/fail-closed.
+- Explicit `--tools` activation was required to exercise `grep`, `find`, and `ls`; this does not imply they are active in Pi's default four-tool configuration.
@@ -0,0 +1,99 @@
+# PR merge squash message field
+
+- **Charter:** `/home/hermes/agent-work/CHARTER-PRMERGE-MESSAGE-FIELD.md`
+- **Owner:** `be-coder-08`
+- **Branch:** `fix/pr-merge-message-field`
+- **Base:** remote `main` / local `origin/main` at `85d2108e4ed15c744ad3b87a5b629e7b2d39405a`
+- **Estate:** HOMELAB tooling shared by HOMELAB and USC
+
+## Objective
+
+Add an optional, identity-checked Gitea squash message to `pr-merge.sh` so genuine multi-author PRs retain non-poster branch authors without weakening hardcoded squash behavior.
+
+## Binding requirements
+
+1. `Do` remains hardcoded to `squash`; no provider/repository default may select merge style.
+2. A verified trailer uses a PR commit's linked `author.login` and that same commit's author email. No `/users/{login}` primary-email lookup occurs. Recorded rationale: this asks only what the provider can answer.
+3. A commit with `author.login` null blocks before merge, prints both the null provider fact and commit email fact, and names the escalation principal.
+4. The BLOCK arm must be observed firing; a normal canonical single-author API payload remains explicit squash plus its reviewed `head_commit_id`.
+5. Every provider mutation is read back from the provider; no real PR is merged during tests.
+
+## Derived interface decisions
+
+- Add `--co-author-trailers` rather than accepting arbitrary message text. The wrapper enumerates PR commits and constructs trailers, making an unchecked `Co-authored-by` line unexpressible.
+- Require `--escalate-to PRINCIPAL` with `--co-author-trailers`, so the BLOCK diagnostic always names a principal rather than a generic role.
+- Do not expose `MergeTitleField` separately. When trailers exist, set it from the provider PR title and set `MergeMessageField` only to construction-generated trailers. This preserves one provider source for the title and avoids an unrelated caller-controlled degree of freedom.
+- Preserve first-commit order and emit one trailer per distinct non-poster `author.login`, using that first linked commit's own email.
+
+## Canonical delivery plan
+
+1. Port the capability into the installed source of truth, `packages/mosaic/framework/tools/git/pr-merge.sh`; do not retain `infra/fleet/tools/git` as a second copy.
+2. Preserve canonical `--expect-head`, exact head branch/repository/SHA queue inspection, Gitea atomic head pinning, GitHub `--match-head-commit`, and delete-after-merge semantics.
+3. Do not port the deployed-only `--skip-queue-guard` bypass. Add the focused harness to the canonical framework-shell suite and re-establish RED/GREEN on the packaged baseline.
+4. Deliver through a reviewed package release followed by `mosaic update` with its default framework reseed. The installer snapshots, manifest-syncs framework-owned `tools/**`, and rolls back on failure.
+5. Before either estate relies on the change, require installed/package hash equality, `MergeMessageField` presence, and a green focused harness. Release/reseed ownership is currently unassigned and blocks activation after source merge.
+
+## Evidence
+
+- RED against the byte-identical deployed baseline (`sha256 08a65e8584c5…`): rc 1 with eight named failures. The wrapper rejected `--co-author-trailers`; the null-login path emitted none of the required BLOCK facts/principal; and both verified/ordinary API paths failed the stdin-config credential assertion (ordinary path exposed the fixture token through curl argv). Log: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-message-field-red.log`.
+- GREEN on the deployed-baseline candidate: verified linked multi-author payload, null-login BLOCK, required named principal, explicit squash, stdin-config token transport, and absence of `/users` lookup all passed. Log: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-message-field-green.log`.
+- RED against canonical packaged baseline `c581ef48…`: rc 1 with 32 assertions. It rejects the new option, and the first harness version did not satisfy canonical head branch/repository/SHA metadata. Log: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-packaged-baseline-red.log`. The port adapts the fixture rather than weakening canonical head controls.
+- Provider capability probe against `git.mosaicstack.dev`: authenticated `be-coder-08` POST to deliberately nonexistent PR `2147483647` with both message fields returned JSON HTTP 404; the unauthenticated same request returned JSON HTTP 401 (not the charter's predicted 403). The authenticated-vs-unauthenticated differential proves write authorization resolved while no mergeable subject existed. `tl-mosaic` ruled the literal non-load-bearing: preserve the observed 404/401 pair and do not manufacture a 403 case. No cause was inferred and no real PR was targeted.
+- Provider-generated trailer behavior is not treated as exclusive or absent. The wrapper's VERIFIED/BLOCK decision binds each requested non-poster trailer to commit `author.login` plus that commit's email; it does not assume `MergeMessageField` is the squash's only trailer source. The poster is omitted from the constructed list because the resulting squash author already records the poster; any additional provider-generated trailer is outside this change's unmeasured mechanism.
+- An early candidate SHA-256 `5de32876990e4f26920448cb3220cc7f1146d558b4dd2bc1ee1a2abee2f2cbe6` passed the initial harness, then author-side review found credential-fallback and argv-exposure defects. The live deployed wrapper was atomically restored to baseline SHA-256 `08a65e8584c52c6d41ea1c686f8b95585c21e4b37320a2447eba09359a0e02c1`; the remediated candidate remains only in the worktree.
+
+## Remediation and current review state
+
+1. Token and Basic Auth now use stdin curl configuration, not argv. PR title, contributor email, and the JSON payload also remain out of child argv.
+2. Each credential attempt binds commit inspection and merge. A token failure during either inspection or mutation causes Basic fallback to repeat inspection before mutation; the payload pins the inspected `head_commit_id`.
+3. Focused tests cover token-resolution fail-closed behavior, both HTTP-401 fallback seams, metadata/credential argv absence, null-login BLOCK, explicit squash, canonical reviewed-head binding, unchanged ordinary payload, and retained log-safe provider diagnostics. Token-resolution RED: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-token-resolution-red.log`.
+4. Codex review rounds 3–5 requested retained provider error text, log-safe provider diagnostics, fail-closed credential fallback, stable value-option parsing, and PR-title trailer-injection prevention. These are remediated with regression assertions. A post-remediation independent review is still required.
+5. **Accepted linkage limitation:** `author.login` resolution proves that the commit address maps to a registered provider account. It does not prove that the named principal authored the commit because Git author metadata is self-asserted. This gate checks attribution linkage, not authorship; commit signing is out of scope and currently unadopted. Coordinators explicitly ruled that this does not add a third state.
+6. Codex's sandbox could not execute the harness because its checkout was read-only; that environmental limitation is recorded separately from host-side test results.
+
+## Disposable provider fixture acceptance
+
+- Use a retained scratch repository only, with two branch authors and `author != committer` on at least one commit.
+- Arm A supplies a message-field trailer for one non-poster; record whether that value lands without forcing the partial-pair result into under-specified `APPENDS`/`REPLACES` labels. Demonstrate an absence control.
+- Arm B includes a registered trailer for a different non-poster on a branch commit; record whether it survives or drops. Verify identity through an existing commit whose `author.login` resolves and demonstrate an absence control.
+- Parse landed trailers key-agnostically with `^[A-Za-z-]+-[Bb]y:` and record generated poster pair presence/absence plus resulting poster attribution.
+- Record `/users/<login>` status and raw email only as non-gating estate telemetry. Never read `active`, `visibility`, or any profile field as an identity gate.
+- Use distinct principals: poster `be-coder-08`, merger `Mos`, Arm A `be-coder-07`, and Arm B `be-coder-06`. Capture every trailer-shaped line verbatim and in order. Zero trailer lines means the generator did not fire and the run is `VOID`, not evidence that either arm dropped.
+- Report the same read-back evidence to `mos-claude` on socket `default` and `tl-mosaic` on socket `mosaic-fleet`. Report values rather than mechanism inferences and stop on any poster-attribution regression.
+
+## Fixture preflight
+
+- Retained public repository: `mosaicstack/prmerge-trailer-fixture`; PR `#1`, posted by `be-coder-08` and reserved for merge by `Mos`.
+- Existing `mosaicstack/stack` commits resolve `be-coder-07` and `be-coder-06` through `author.login`; exact addresses are `[email protected]` and `[email protected]`.
+- Non-gating HOMELAB telemetry for authenticated reader `be-coder-08`: `/api/v1/users/be-coder-06` returned HTTP 200 with raw `email` value `[email protected]`.
+- Provider preflight showed PR commit enumeration is newest-first. A new RED test proved that deriving `head_commit_id` from the final array element selected the wrong commit. The candidate now reads `.head.sha` from the authenticated PR endpoint before enumeration, verifies it appears in the commit set, and atomically pins that SHA in the explicit squash payload. RED: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-head-order-red.log`.
+- Fixture PR head `f6ba6e5105031fa21f5ff7bd8e4379d99c16e1de` has `author.login=be-coder-07`, `committer.login=be-coder-08`, and branch-message trailer `Co-authored-by: be-coder-06 <[email protected]>`.
+
+## Fixture result
+
+- `Mos` merged retained fixture PR `#1` through staged candidate SHA-256 `60e779a85fd13b729d859ea7c986d1e9b1641b97991611329226c1b3113ffb6e`; resulting squash commit: `3f550715d9bc716426fd355a65fe997b3a90fa7d` with one parent.
+- Provider read-back: poster/commit author `be-coder-08`, committer/merger `Mos`. The run is non-void.
+- Trailer-shaped lines, verbatim and in order:
+  1. `Co-authored-by: be-coder-07 <[email protected]>`
+  2. `Co-authored-by: be-coder-08 <[email protected]>`
+- Arm A supplied field value (`be-coder-07`) landed. Arm B branch trailer (`be-coder-06`) dropped. Both fabricated absence controls remained absent. No `Co-committed-by:` line landed.
+- The candidate payload construction explicitly excludes the poster and supplied only the Arm A `be-coder-07` line. Therefore the landed poster line was provider-generated, not candidate-composed. The raw result supports `FIELD LANDS`, `BRANCH DROPS`, and `POSTER GENERATED`; it does not support a claim that candidate code supplied the poster. Evidence: `/home/hermes/agent-work/be-coder-08/evidence/prmerge-fixture-readback.log` and the retained provider object.
+- Retained fixture PR `#2` measured the N=2 shape needed by `#1030`: supplied `be-coder-07` then `be-coder-06`; both landed in that order, followed by the provider-generated poster line. No truncation or dedup occurred at N=2. Resulting squash: `39db9d13aed0…`.
+
+## Current hold point
+
+PR `mosaicstack/stack#1066` is open. Its first frozen head `f4b162fa…` was terminal-green in Woodpecker `mosaic` pipeline `#2225`, but that evidence becomes stale when the canonical port moves the head. The deployed wrapper remains baseline `08a65e85…`; no manual copy will occur. Canonical port tests, commit amendment, rebase, one guarded force-with-lease, exact-head CI, and new independent review remain. Even after source merge, activation remains blocked on an assigned package-release/reseed owner and installed-byte read-back.
+
+## Security review 96 remediation
+
+Exact reviewed predecessor head: `1ceb11058f64dd7f4a817ceb2124f980a1c4dd23`.
+
+RED-first focused harness produced 10 named failures: all curl calls lacked size/time/connect bounds; raw ESC email reached mutation; oversized and stalled curl failures were discarded and reached mutation; nonempty Basic output with resolver rc 91 authorized mutation.
+
+Security remediation:
+
+- Removed the cross-principal HTTP-401 Basic fallback. Both inspection-401 and merge-401 paths now refuse without Basic resolution or mutation; `get_gitea_basic_auth` references in the merge subject are 0.
+- Applied `--max-filesize`, `--max-time`, and `--connect-timeout` to all 3/3 provider curl sites and fail closed on curl transport rc at all 3/3 sites.
+- Required linked email bytes to be ASCII and printable before constructing `MergeMessageField`; guarded construction sites 1/1.
+
+GREEN: message-field, exact-head, empty-UID/API, queue branch/repository/SHA, bash syntax, ShellCheck, and diff check pass. R7 total-removal mutants went RED: email guard 3 rows; bound switches 1 row; transport-rc guards 4 rows; HTTP-401 refusal 3 rows. R7 bound: mutants prove total removal only; explicit denominators above prove site coverage.
@@ -0,0 +1 @@
+I invoked this registered command to authorize lease promotion; follow the local seat broker's injected receipt confirmation instruction exactly.
@@ -32,6 +32,18 @@
        ]
      }
    ],
+    "UserPromptSubmit": [
+      {
+        "matcher": "^/mosaic-promote$",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/promote-begin.py",
+            "timeout": 15
+          }
+        ]
+      }
+    ],
    "PreToolUse": [
      {
        "matcher": ".*",
@@ -81,8 +93,8 @@
        "hooks": [
          {
            "type": "command",
-            "command": "python3 ~/.config/mosaic/tools/lease-broker/receipt-observer-client.py --runtime claude --latest-entry",
-            "timeout": 3
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/receipt-observer-client.py --runtime claude --latest-entry; observer_status=$?; python3 ~/.config/mosaic/tools/lease-broker/promote-complete.py; exit $observer_status",
+            "timeout": 15
          },
          {
            "type": "command",
@@ -153,7 +153,24 @@ if [[ $link_only -eq 1 ]]; then
  exit 0
 fi

+# Skills are linked into the MOSAIC-OWNED harness homes, never a base install.
+# Paths mirror the config-dir env vars the launcher injects (HARNESS_HOME_ENV in
+# commands/launch.js):
+#   claude   CLAUDE_CONFIG_DIR      -> <home>/skills
+#   pi       PI_CODING_AGENT_DIR    -> <home>/skills   (replaces ~/.pi/agent)
+#   codex    CODEX_HOME             -> <home>/skills
+#   opencode XDG_CONFIG_HOME        -> <home>/opencode/skills  (XDG adds a level)
 link_targets=(
+  "$MOSAIC_HOME/.claude/skills"
+  "$MOSAIC_HOME/.codex/skills"
+  "$MOSAIC_HOME/.opencode/opencode/skills"
+  "$MOSAIC_HOME/.pi/skills"
+)
+
+# Pre-isolation installs planted the same symlink farm directly in the operator's
+# base installs. Those are now orphaned: the launcher no longer reads them, but
+# they persist and make a "clean" base install look mosaic-managed.
+legacy_link_targets=(
  "$HOME/.claude/skills"
  "$HOME/.codex/skills"
  "$HOME/.config/opencode/skills"
@@ -245,13 +262,72 @@ prune_stale_links_in_target() {
    # -m resolves lexical dangling targets too. If resolution fails, ownership
    # is unproven and the link must be preserved.
    resolved="$(readlink -m "$link_path" 2>/dev/null || true)"
-    if [[ -n "$resolved" && "$resolved" == "$canonical_real/"* ]]; then
+    # $canonical_real must be length-checked BEFORE use as a prefix: if it were
+    # ever empty, "$resolved" == "$canonical_real/"* collapses to == "/"* and
+    # matches every absolute path. Combined with the is_mosaic_skill_name skip
+    # above, that inverts the function precisely — it would delete exactly the
+    # FOREIGN symlinks and keep the mosaic ones. (#1087, reported by mos-claude.)
+    if [[ -n "$resolved" && -n "$canonical_real" && "$resolved" == "$canonical_real/"* ]]; then
      rm -f "$link_path"
      echo "[mosaic-skills] Removed stale retired skill link: $link_path"
    fi
  done < <(find "$target_dir" -mindepth 1 -maxdepth 1 -type l -print0)
 }

+# Remove mosaic-owned symlinks left in a base install by a pre-isolation sync.
+#
+# Ownership is proven by RESOLUTION, not by name: only links resolving inside the
+# canonical or local skills dirs are removed. Anything else — a real directory, a
+# link elsewhere, an unresolvable link — is left untouched. This mirrors the
+# refusal in commands/skill.js ("only symlinks pointing inside the Mosaic skills
+# directory are managed") and preserves e.g. codex's own `.system` dir.
+#
+# The directory itself is kept: mosaic-doctor warns when ~/.pi/agent/skills is
+# missing, and an empty dir is the correct end state, not an absent one.
+cleanup_legacy_target() {
+  local target_dir="$1"
+  local removed=0 kept=0
+
+  [[ -d "$target_dir" ]] || return 0
+
+  while IFS= read -r -d '' link_path; do
+    local resolved owned=0
+    resolved="$(readlink -m "$link_path" 2>/dev/null || true)"
+
+    # Guard the empty-prefix trap: an unset *_real would make "$resolved" == "/"*
+    # match every absolute path and delete foreign links.
+    if [[ -n "$resolved" ]]; then
+      if [[ -n "$canonical_real" && "$resolved" == "$canonical_real/"* ]]; then
+        owned=1
+      elif [[ -n "$local_real" && "$resolved" == "$local_real/"* ]]; then
+        owned=1
+      fi
+    fi
+
+    if [[ $owned -eq 1 ]]; then
+      rm -f "$link_path"
+      removed=$((removed + 1))
+    else
+      kept=$((kept + 1))
+    fi
+  done < <(find "$target_dir" -mindepth 1 -maxdepth 1 -type l -print0)
+
+  if [[ $removed -gt 0 ]]; then
+    echo "[mosaic-skills] Legacy cleanup: removed $removed mosaic symlink(s) from $target_dir (preserved $kept foreign)"
+  fi
+}
+
+for legacy in "${legacy_link_targets[@]}"; do
+  # Skip anything that is also a current target, so isolation can never
+  # self-destruct if the two lists ever overlap.
+  skip=0
+  for target in "${link_targets[@]}"; do
+    [[ "$legacy" == "$target" ]] && skip=1
+  done
+  [[ $skip -eq 1 ]] && continue
+  cleanup_legacy_target "$legacy"
+done
+
 for target in "${link_targets[@]}"; do
  mkdir -p "$target"

@@ -1,6 +1,6 @@
 #!/bin/bash
 # pr-merge.sh - Merge pull requests on Gitea or GitHub
-# Usage: pr-merge.sh -n PR_NUMBER [-m squash] [-d]
+# Usage: pr-merge.sh -n PR_NUMBER [-m squash] [-d] [--expect-head SHA] [--co-author-trailers --escalate-to PRINCIPAL]

 set -euo pipefail

@@ -14,6 +14,8 @@ MERGE_METHOD="squash"
 DELETE_BRANCH=false
 DRY_RUN=false
 EXPECT_HEAD=""
+CO_AUTHOR_TRAILERS=false
+ESCALATE_TO=""

 usage() {
    cat <<EOF
@@ -27,12 +29,16 @@ Options:
    -d, --delete-branch     Delete the head branch after merge
        --dry-run           Run metadata/login preflight without merging
        --expect-head SHA   Refuse unless the PR head matches this full commit SHA
+        --co-author-trailers Build verified trailers from linked PR commit authors
+        --escalate-to NAME  Named principal for an unresolved-author BLOCK
    -h, --help              Show this help message

 Examples:
    $(basename "$0") -n 42                    # Merge PR #42
    $(basename "$0") -n 42 -m squash          # Squash merge
    $(basename "$0") -n 42 -d                 # Squash merge and delete branch
+    $(basename "$0") -n 42 --expect-head 0123456789abcdef0123456789abcdef01234567
+    $(basename "$0") -n 42 --co-author-trailers --escalate-to tl-mosaic
 EOF
    exit "${1:-1}"
 }
@@ -57,9 +63,25 @@ while [[ $# -gt 0 ]]; do
            shift
            ;;
        --expect-head)
+            if [[ $# -lt 2 ]]; then
+                echo "Error: --expect-head requires one full commit SHA." >&2
+                exit 1
+            fi
            EXPECT_HEAD="$2"
            shift 2
            ;;
+        --co-author-trailers)
+            CO_AUTHOR_TRAILERS=true
+            shift
+            ;;
+        --escalate-to)
+            if [[ $# -lt 2 ]]; then
+                echo "Error: --escalate-to requires one principal name." >&2
+                exit 1
+            fi
+            ESCALATE_TO="$2"
+            shift 2
+            ;;
        -h|--help)
            usage 0
            ;;
@@ -88,17 +110,30 @@ if [[ -n "$EXPECT_HEAD" && ! "$EXPECT_HEAD" =~ ^[0-9a-fA-F]{40}$ ]]; then
    echo "Error: --expect-head must be a full 40-character hexadecimal commit SHA." >&2
    exit 1
 fi
+if [[ "$CO_AUTHOR_TRAILERS" == true && -z "$ESCALATE_TO" ]]; then
+    echo "Error: --co-author-trailers requires --escalate-to with a named principal." >&2
+    exit 1
+fi
+if [[ -n "$ESCALATE_TO" && ! "$ESCALATE_TO" =~ ^[A-Za-z0-9_.-]+$ ]]; then
+    echo "Error: --escalate-to must be one exact principal name." >&2
+    exit 1
+fi
+if [[ "$CO_AUTHOR_TRAILERS" != true && -n "$ESCALATE_TO" ]]; then
+    echo "Error: --escalate-to is valid only with --co-author-trailers." >&2
+    exit 1
+fi

 PR_METADATA="$("$SCRIPT_DIR/pr-metadata.sh" -n "$PR_NUMBER")"
 BASE_BRANCH="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("baseRefName") or "").strip())')"
 HEAD_BRANCH="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("headRefName") or "").strip())')"
 HEAD_SHA="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("headRefOid") or "").strip())')"
 HEAD_REPO="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; value=json.load(sys.stdin).get("headRepository") or ""; print((value.get("nameWithOwner") or value.get("full_name") or "") if isinstance(value, dict) else str(value).strip())')"
+PR_TITLE="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; print((json.load(sys.stdin).get("title") or "").strip())')"
+PR_AUTHOR="$(printf '%s' "$PR_METADATA" | python3 -c 'import json, sys; value=json.load(sys.stdin).get("author") or ""; print((value.get("login") or "").strip() if isinstance(value, dict) else str(value).strip())')"
 if [[ "$BASE_BRANCH" != "main" ]]; then
    echo "Error: Mosaic policy allows merges only for PRs targeting 'main' (found '$BASE_BRANCH')." >&2
    exit 1
 fi
-
 if [[ -z "$HEAD_BRANCH" || -z "$HEAD_REPO" || ! "$HEAD_SHA" =~ ^[0-9a-fA-F]{40}$ ]]; then
    echo "Error: Could not resolve the PR head branch, repository, and full commit SHA for queue inspection." >&2
    exit 1
@@ -122,70 +157,442 @@ PLATFORM=$(detect_platform)
 OWNER=$(get_repo_owner)
 REPO=$(get_repo_name)

-merge_gitea_with_api() {
-    local host="$1" api_url token basic_auth body_file raw_code payload
-    api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/merge"
-    mkdir -p "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}"
-    body_file=$(mktemp "${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}/pr-merge-api-response.XXXXXX")
-    payload=$(python3 - "$HEAD_SHA" "$DELETE_BRANCH" <<'PY'
+write_curl_auth_config() {
+    local mode="$1" credential="$2"
+    printf '%s' "$credential" | python3 -c '
+import sys
+mode = sys.argv[1]
+credential = sys.stdin.read()
+if not credential or any(char in credential for char in "\r\n"):
+    raise SystemExit(1)
+escaped = credential.replace("\\", "\\\\").replace("\"", "\\\"")
+if mode == "token":
+    print(f"header = \"Authorization: token {escaped}\"")
+elif mode == "basic":
+    print(f"user = \"{escaped}\"")
+else:
+    raise SystemExit(1)
+' "$mode"
+}
+
+LAST_GITEA_HTTP_CODE="000"
+LAST_GITEA_ERROR=""
+MERGE_TEMP_DIRS=()
+GITEA_CURL_MAX_BYTES="${MOSAIC_GITEA_CURL_MAX_BYTES:-1048576}"
+GITEA_CURL_MAX_TIME="${MOSAIC_GITEA_CURL_MAX_TIME_SEC:-30}"
+GITEA_CURL_CONNECT_TIMEOUT="${MOSAIC_GITEA_CURL_CONNECT_TIMEOUT_SEC:-10}"
+for bound in "$GITEA_CURL_MAX_BYTES" "$GITEA_CURL_MAX_TIME" "$GITEA_CURL_CONNECT_TIMEOUT"; do
+    if [[ ! "$bound" =~ ^[1-9][0-9]*$ ]]; then
+        echo "Error: Gitea curl bounds must be positive integers; refusing request." >&2
+        exit 1
+    fi
+done
+GITEA_CURL_BOUNDS=(
+    --max-filesize "$GITEA_CURL_MAX_BYTES"
+    --max-time "$GITEA_CURL_MAX_TIME"
+    --connect-timeout "$GITEA_CURL_CONNECT_TIMEOUT"
+)
+
+format_gitea_error_response() {
+    local response_file="$1"
+    python3 - "$response_file" <<'PY'
 import json
 import sys

-head_sha, delete_branch = sys.argv[1:]
+with open(sys.argv[1], "rb") as handle:
+    raw = handle.read(65536)
+try:
+    response = json.loads(raw.decode("utf-8", errors="replace"))
+except (UnicodeDecodeError, json.JSONDecodeError):
+    message = "non-JSON response omitted"
+else:
+    if isinstance(response, dict):
+        message = response.get("message") or response.get("error")
+        if not message and response.get("errors") is not None:
+            message = json.dumps(response["errors"], separators=(",", ":"))
+    else:
+        message = None
+    if not message:
+        message = "JSON response contained no error message"
+message = str(message)
+if len(message) > 500:
+    message = message[:500] + "..."
+print(ascii(message))
+PY
+}
+
+cleanup_merge_temp_dirs() {
+    local path
+    for path in "${MERGE_TEMP_DIRS[@]}"; do
+        [[ -n "$path" ]] && rm -rf -- "$path"
+    done
+}
+trap cleanup_merge_temp_dirs EXIT
+trap 'exit 130' INT
+trap 'exit 143' TERM
+
+fetch_gitea_pr_head() {
+    local host="$1" auth_mode="$2" credential="$3" work_root="$4"
+    local response_file raw_code api_url auth_config curl_rc
+    response_file=$(mktemp "$work_root/pr-merge-pr.XXXXXX")
+    api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}"
+    if ! auth_config=$(write_curl_auth_config "$auth_mode" "$credential"); then
+        echo "Error: Could not construct Gitea authentication config; refusing request." >&2
+        rm -f "$response_file"
+        return 1
+    fi
+    raw_code=$(curl -sS -K - "${GITEA_CURL_BOUNDS[@]}" -w '%{http_code}' -o "$response_file" \
+        -H "User-Agent: curl/8" "$api_url" <<<"$auth_config")
+    curl_rc=$?
+    LAST_GITEA_HTTP_CODE="${raw_code:-000}"
+    if [[ "$curl_rc" -ne 0 ]]; then
+        LAST_GITEA_ERROR="curl transport failed (rc=$curl_rc)"
+        rm -f "$response_file"
+        return 1
+    fi
+    if [[ ! "$raw_code" =~ ^2 ]]; then
+        LAST_GITEA_ERROR=$(format_gitea_error_response "$response_file")
+        rm -f "$response_file"
+        return 1
+    fi
+    if ! python3 - "$response_file" <<'PY'
+import json
+import re
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as handle:
+    pull = json.load(handle)
+head = pull.get("head") if isinstance(pull, dict) else None
+sha = str(head.get("sha") or "") if isinstance(head, dict) else ""
+if not re.fullmatch(r"[0-9a-fA-F]{40}", sha):
+    raise SystemExit(1)
+print(sha)
+PY
+    then
+        echo "Error: Gitea PR response has no valid head SHA; refusing merge." >&2
+        rm -f "$response_file"
+        return 1
+    fi
+    rm -f "$response_file"
+}
+
+fetch_gitea_pr_commits() {
+    local host="$1" auth_mode="$2" credential="$3" work_root="$4"
+    local page page_file combined_file merged_file raw_code page_count api_url auth_config curl_rc
+    mkdir -p "$work_root"
+    if ! auth_config=$(write_curl_auth_config "$auth_mode" "$credential"); then
+        echo "Error: Could not construct Gitea authentication config; refusing request." >&2
+        return 1
+    fi
+    combined_file=$(mktemp "$work_root/pr-merge-commits.XXXXXX")
+    printf '[]' > "$combined_file"
+
+    page=1
+    while true; do
+        page_file=$(mktemp "$work_root/pr-merge-commits-page.XXXXXX")
+        api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/commits?limit=50&page=${page}"
+        raw_code=$(curl -sS -K - "${GITEA_CURL_BOUNDS[@]}" -w '%{http_code}' -o "$page_file" \
+            -H "User-Agent: curl/8" "$api_url" <<<"$auth_config")
+        curl_rc=$?
+        LAST_GITEA_HTTP_CODE="${raw_code:-000}"
+        if [[ "$curl_rc" -ne 0 ]]; then
+            LAST_GITEA_ERROR="curl transport failed (rc=$curl_rc)"
+            rm -f "$page_file" "$combined_file"
+            return 1
+        fi
+        if [[ ! "$raw_code" =~ ^2 ]]; then
+            LAST_GITEA_ERROR=$(format_gitea_error_response "$page_file")
+            rm -f "$page_file" "$combined_file"
+            return 1
+        fi
+
+        if ! page_count=$(python3 - "$page_file" <<'PY'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as handle:
+    page = json.load(handle)
+if not isinstance(page, list):
+    raise SystemExit(1)
+print(len(page))
+PY
+        ); then
+            echo "Error: Gitea PR commits response is not a JSON array; refusing merge." >&2
+            rm -f "$page_file" "$combined_file"
+            return 1
+        fi
+
+        merged_file=$(mktemp "$work_root/pr-merge-commits-merged.XXXXXX")
+        if ! python3 - "$combined_file" "$page_file" > "$merged_file" <<'PY'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as handle:
+    combined = json.load(handle)
+with open(sys.argv[2], encoding="utf-8") as handle:
+    page = json.load(handle)
+json.dump(combined + page, sys.stdout, separators=(",", ":"))
+PY
+        then
+            echo "Error: Could not combine paginated PR commit metadata; refusing merge." >&2
+            rm -f "$page_file" "$combined_file" "$merged_file"
+            return 1
+        fi
+        mv "$merged_file" "$combined_file"
+        rm -f "$page_file"
+
+        if [[ "$page_count" -lt 50 ]]; then
+            break
+        fi
+        page=$((page + 1))
+        if [[ "$page" -gt 1000 ]]; then
+            echo "Error: PR commit pagination exceeded 1000 pages; refusing merge." >&2
+            rm -f "$combined_file"
+            return 1
+        fi
+    done
+
+    cat "$combined_file"
+    rm -f "$combined_file"
+}
+
+# LIMITATION: author.login resolution proves the commit address maps to a registered account.
+# It does NOT prove the named principal authored the commit — git author metadata is self-asserted.
+# This gate checks ATTRIBUTION LINKAGE, not AUTHORSHIP. Commit signing is out of scope and unadopted.
+build_coauthor_message_fields() {
+    local commits_file="$1" context_file="$2" head_file="$3"
+    python3 - "$commits_file" "$context_file" "$head_file" <<'PY'
+import json
+import re
+import sys
+
+commits_path, context_path, head_path = sys.argv[1:]
+with open(commits_path, encoding="utf-8") as handle:
+    commits = json.load(handle)
+head_sha = open(head_path, encoding="utf-8").read().strip()
+context_parts = open(context_path, "rb").read().split(b"\0")
+if len(context_parts) != 4 or context_parts[-1] != b"":
+    raise SystemExit(1)
+poster, title, principal = (part.decode("utf-8") for part in context_parts[:3])
+
+if not isinstance(commits, list) or not commits:
+    print(
+        f"BLOCK: provider returned no PR commits; author identity is unmeasurable. "
+        f"Refusing merge; escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+if not poster:
+    print(
+        f"BLOCK: PR poster login is empty; refusing merge; "
+        f"escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+
+if not re.fullmatch(r"[0-9a-fA-F]{40}", head_sha):
+    print(
+        f"BLOCK: inspected PR head SHA is invalid; refusing merge; "
+        f"escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+
+seen = set()
+trailers = []
+head_seen = False
+for item in commits:
+    if not isinstance(item, dict):
+        print(f"BLOCK: malformed PR commit metadata; escalate to named principal '{principal}'.", file=sys.stderr)
+        raise SystemExit(75)
+    sha = str(item.get("sha") or "<unknown>")
+    if sha == head_sha:
+        head_seen = True
+    commit = item.get("commit") if isinstance(item.get("commit"), dict) else {}
+    commit_author = commit.get("author") if isinstance(commit.get("author"), dict) else {}
+    email = str(commit_author.get("email") or "").strip()
+    provider_author = item.get("author") if isinstance(item.get("author"), dict) else {}
+    login = str(provider_author.get("login") or "").strip()
+
+    if not login:
+        diagnostic_email = email or "<missing>"
+        print(
+            f"BLOCK: commit {sha!r} has author.login=NULL while "
+            f"commit.author.email={diagnostic_email!r}; refusing merge; "
+            f"escalate to named principal '{principal}'.",
+            file=sys.stderr,
+        )
+        raise SystemExit(75)
+    if (
+        not email.isascii()
+        or not email.isprintable()
+        or not re.fullmatch(r"[A-Za-z0-9_.-]+", login)
+        or not re.fullmatch(r"[^<>\s]+@[^<>\s]+", email)
+    ):
+        print(
+            f"BLOCK: commit {sha!r} has unusable linked identity "
+            f"author.login={login!r}, commit.author.email={email!r}; refusing merge; "
+            f"escalate to named principal '{principal}'.",
+            file=sys.stderr,
+        )
+        raise SystemExit(75)
+    if login == poster or login in seen:
+        continue
+    seen.add(login)
+    trailers.append(f"Co-authored-by: {login} <{email}>")
+
+if not head_seen:
+    print(
+        f"BLOCK: inspected PR head is absent from commit enumeration; refusing merge; "
+        f"escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+if not trailers:
+    print("{}")
+    raise SystemExit(0)
+if not title:
+    print(
+        f"BLOCK: PR title is empty; refusing merge; escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+if not title.isprintable() or re.match(r"^[A-Za-z-]+-[Bb]y:", title):
+    print(
+        f"BLOCK: PR title is not one printable, non-trailer line; refusing merge; "
+        f"escalate to named principal '{principal}'.",
+        file=sys.stderr,
+    )
+    raise SystemExit(75)
+
+print(json.dumps({
+    "MergeTitleField": title,
+    "MergeMessageField": "\n".join(trailers),
+}, separators=(",", ":")))
+PY
+}
+
+merge_gitea_api_attempt() {
+    local host="$1" auth_mode="$2" credential="$3"
+    local api_url attempt_dir body_file raw_code commits_file fields_file context_file head_file payload_file work_root attempt_rc auth_config curl_rc
+    LAST_GITEA_HTTP_CODE="000"
+    LAST_GITEA_ERROR=""
+    api_url="https://${host}/api/v1/repos/${OWNER}/${REPO}/pulls/${PR_NUMBER}/merge"
+    work_root="${AGENT_WORK_ROOT:-${HOME:-/tmp}/mosaic/agent-work}"
+    mkdir -p "$work_root"
+    attempt_dir=$(mktemp -d "$work_root/pr-merge-attempt.XXXXXX")
+    chmod 0700 "$attempt_dir"
+    MERGE_TEMP_DIRS+=("$attempt_dir")
+    body_file=$(mktemp "$attempt_dir/api-response.XXXXXX")
+    fields_file=$(mktemp "$attempt_dir/message-fields.XXXXXX")
+    payload_file=$(mktemp "$attempt_dir/payload.XXXXXX")
+    printf '{}' > "$fields_file"
+
+    if [[ "$CO_AUTHOR_TRAILERS" == true ]]; then
+        commits_file=$(mktemp "$attempt_dir/pr-merge-commits-input.XXXXXX")
+        context_file=$(mktemp "$attempt_dir/pr-merge-message-context.XXXXXX")
+        head_file=$(mktemp "$attempt_dir/pr-merge-head-input.XXXXXX")
+        printf '%s\0%s\0%s\0' "$PR_AUTHOR" "$PR_TITLE" "$ESCALATE_TO" > "$context_file"
+        if fetch_gitea_pr_head "$host" "$auth_mode" "$credential" "$attempt_dir" > "$head_file"; then
+            :
+        else
+            attempt_rc=$?
+            rm -f "$body_file" "$fields_file" "$payload_file" "$commits_file" "$context_file" "$head_file"
+            return "$attempt_rc"
+        fi
+        if [[ "$(<"$head_file")" != "$HEAD_SHA" ]]; then
+            echo "BLOCK: authenticated PR head moved from reviewed $HEAD_SHA to $(<"$head_file"); refusing merge; escalate to named principal '$ESCALATE_TO'." >&2
+            rm -f "$body_file" "$fields_file" "$payload_file" "$commits_file" "$context_file" "$head_file"
+            return 75
+        fi
+        if fetch_gitea_pr_commits "$host" "$auth_mode" "$credential" "$attempt_dir" > "$commits_file"; then
+            :
+        else
+            attempt_rc=$?
+            rm -f "$body_file" "$fields_file" "$payload_file" "$commits_file" "$context_file" "$head_file"
+            return "$attempt_rc"
+        fi
+        if build_coauthor_message_fields "$commits_file" "$context_file" "$head_file" > "$fields_file"; then
+            :
+        else
+            attempt_rc=$?
+            rm -f "$body_file" "$fields_file" "$payload_file" "$commits_file" "$context_file" "$head_file"
+            return "$attempt_rc"
+        fi
+        rm -f "$commits_file" "$context_file" "$head_file"
+    fi
+
+    if ! python3 - "$fields_file" "$HEAD_SHA" "$DELETE_BRANCH" > "$payload_file" <<'PY'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as handle:
+    fields = json.load(handle)
+head_sha, delete_branch = sys.argv[2:]
 payload = {"Do": "squash", "head_commit_id": head_sha}
 if delete_branch == "true":
    payload["delete_branch_after_merge"] = True
+payload.update(fields)
+allowed = {"Do", "head_commit_id", "delete_branch_after_merge", "MergeTitleField", "MergeMessageField"}
+if payload.get("Do") != "squash" or set(payload) - allowed:
+    raise SystemExit(1)
 print(json.dumps(payload, separators=(",", ":")))
 PY
-)
-
-    token=$(get_gitea_token "$host" || true)
-    if [[ -n "$token" ]]; then
-        raw_code=$(curl -sS -w '%{http_code}' -o "$body_file" \
-            -X POST \
-            -H "User-Agent: curl/8" \
-            -H "Authorization: token $token" \
-            -H 'Content-Type: application/json' \
-            -d "$payload" \
-            "$api_url" || true)
-        if [[ "$raw_code" =~ ^2 ]]; then
-            rm -f "$body_file"
-            return 0
-        fi
+    then
+        rm -f "$body_file" "$fields_file" "$payload_file"
+        return 1
    fi
+    rm -f "$fields_file"

-    basic_auth=$(get_gitea_basic_auth "$host" || true)
-    if [[ -n "$basic_auth" ]]; then
-        raw_code=$(curl -sS -w '%{http_code}' -o "$body_file" \
-            -X POST \
-            -u "$basic_auth" \
-            -H "User-Agent: curl/8" \
-            -H 'Content-Type: application/json' \
-            -d "$payload" \
-            "$api_url" || true)
-        if [[ "$raw_code" =~ ^2 ]]; then
-            rm -f "$body_file"
-            return 0
-        fi
+    if ! auth_config=$(write_curl_auth_config "$auth_mode" "$credential"); then
+        echo "Error: Could not construct Gitea authentication config; refusing request." >&2
+        rm -f "$body_file" "$payload_file"
+        return 1
    fi
+    raw_code=$(curl -sS -K - "${GITEA_CURL_BOUNDS[@]}" -w '%{http_code}' -o "$body_file" \
+        -X POST -H "User-Agent: curl/8" \
+        -H 'Content-Type: application/json' \
+        --data-binary "@$payload_file" "$api_url" <<<"$auth_config")
+    curl_rc=$?
+    LAST_GITEA_HTTP_CODE="${raw_code:-000}"
+    if [[ "$curl_rc" -ne 0 ]]; then
+        LAST_GITEA_ERROR="curl transport failed (rc=$curl_rc)"
+        rm -f "$body_file" "$payload_file"
+        rm -rf -- "$attempt_dir"
+        return 1
+    fi
+    if [[ ! "$raw_code" =~ ^2 ]]; then
+        LAST_GITEA_ERROR=$(format_gitea_error_response "$body_file")
+    fi
+    rm -f "$body_file" "$payload_file"
+    rm -rf -- "$attempt_dir"
+    [[ "$raw_code" =~ ^2 ]]
+}

-    python3 - "${raw_code:-000}" "$body_file" <<'PY' >&2
-import json
-import sys
-code, path = sys.argv[1], sys.argv[2]
-try:
-    with open(path, encoding="utf-8", errors="replace") as handle:
-        raw = handle.read(500)
-    data = json.loads(raw) if raw else {}
-    message = data.get("message") or data.get("error") or raw or "empty response"
-except Exception:
-    try:
-        message = open(path, encoding="utf-8", errors="replace").read(500) or "empty response"
-    except Exception:
-        message = "unreadable response"
-print(f"Error: Gitea API merge failed with HTTP {code}: {message}")
-PY
-    rm -f "$body_file"
+merge_gitea_with_api() {
+    local host="$1" token attempt_rc
+
+    if ! token=$(get_gitea_token "$host"); then
+        echo "Error: Could not resolve the required Gitea token; refusing merge without changing principals." >&2
+        return 1
+    fi
+    if [[ -z "$token" ]]; then
+        echo "Error: Required Gitea token resolved empty; refusing merge without changing principals." >&2
+        return 1
+    fi
+    if merge_gitea_api_attempt "$host" token "$token"; then
+        return 0
+    else
+        attempt_rc=$?
+    fi
+    if [[ "$attempt_rc" -eq 75 ]]; then
+        return 75
+    fi
+    if [[ "$LAST_GITEA_HTTP_CODE" != "401" ]]; then
+        echo "Error: Gitea API merge failed with the identity-bound token (HTTP ${LAST_GITEA_HTTP_CODE:-000}).${LAST_GITEA_ERROR:+ Provider response: $LAST_GITEA_ERROR}" >&2
+        return 1
+    fi
+    echo "Error: Gitea API rejected the identity-bound token with HTTP 401; refusing cross-principal credential fallback." >&2
    return 1
 }

@@ -195,11 +602,10 @@ if [[ "$DRY_RUN" == true ]]; then
            echo "Error: Cannot determine host from origin remote URL" >&2
            exit 1
        }
-        TEA_LOGIN="$(get_gitea_login_for_host "$HOST" || true)"
-        if [[ -n "$TEA_LOGIN" ]]; then
-            echo "Dry run: would merge PR #$PR_NUMBER on $HOST with tea login '$TEA_LOGIN' (base=$BASE_BRANCH, method=squash)."
+        if [[ "$CO_AUTHOR_TRAILERS" == true ]]; then
+            echo "Dry run: would verify PR commit authors and merge PR #$PR_NUMBER on $HOST with authenticated Gitea API message fields (base=$BASE_BRANCH, method=squash)."
        else
-            echo "Dry run: would merge PR #$PR_NUMBER on $HOST with authenticated Gitea API fallback (base=$BASE_BRANCH, method=squash)."
+            echo "Dry run: would merge PR #$PR_NUMBER on $HOST with the authenticated exact-head Gitea API path (base=$BASE_BRANCH, method=squash)."
        fi
    else
        echo "Dry run: would merge PR #$PR_NUMBER on $PLATFORM (base=$BASE_BRANCH, method=squash)."
@@ -209,6 +615,10 @@ fi

 case "$PLATFORM" in
    github)
+        if [[ "$CO_AUTHOR_TRAILERS" == true ]]; then
+            echo "Error: --co-author-trailers currently requires the Gitea REST message-field contract." >&2
+            exit 1
+        fi
        cmd=(gh pr merge "$PR_NUMBER" --squash --match-head-commit "$HEAD_SHA")
        [[ "$DELETE_BRANCH" == true ]] && cmd+=(--delete-branch)
        "${cmd[@]}"
@@ -219,7 +629,7 @@ case "$PLATFORM" in
            exit 1
        }
        # Gitea's API head_commit_id is an atomic compare-and-merge precondition.
-        # tea cannot express it, so exact-head merges use the authenticated API path.
+        # tea cannot express it, so every Gitea merge uses the authenticated API path.
        merge_gitea_with_api "$HOST"
        ;;
    *)
@@ -51,22 +51,23 @@ for arg in "$@"; do
        prev=""
        continue
    fi
-    if [[ "$prev" == "-d" ]]; then
+    if [[ "$prev" == "data" ]]; then
        post_data="$arg"
+        [[ "$post_data" == @* ]] && post_data=$(<"${post_data#@}")
        prev=""
        continue
    fi
-    if [[ "$arg" == "-o" ]]; then
-        prev="-o"
+    if [[ "$prev" == "config" ]]; then
+        [[ "$arg" == "-" ]] && cat >/dev/null
+        prev=""
        continue
    fi
-    if [[ "$arg" == "-d" ]]; then
-        prev="-d"
-        continue
-    fi
-    if [[ "$arg" == "-w" ]]; then
-        write_code=true
-    fi
+    case "$arg" in
+        -o) prev="-o" ;;
+        -d|--data|--data-binary) prev="data" ;;
+        -K|--config) prev="config" ;;
+        -w) write_code=true ;;
+    esac
 done
 emit_response() {
    local body="$1"
@@ -36,13 +36,30 @@ cat > "$WORK_DIR/gitea/curl" <<'SH'
 #!/usr/bin/env bash
 set -euo pipefail
 payload=""
-for ((i=1; i<=$#; i++)); do
-    if [[ "${!i}" == "-d" ]]; then
-        j=$((i + 1))
-        payload="${!j}"
-    fi
+out_file=""
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -d|--data|--data-binary)
+            payload="$2"
+            [[ "$payload" == @* ]] && payload=$(<"${payload#@}")
+            shift 2
+            ;;
+        -o)
+            out_file="$2"
+            shift 2
+            ;;
+        -K|--config)
+            [[ "$2" == "-" ]] && cat >/dev/null
+            shift 2
+            ;;
+        -w|-X|-H)
+            shift 2
+            ;;
+        *) shift ;;
+    esac
 done
 printf '%s' "$payload" > "${MOSAIC_MERGE_PAYLOAD_LOG:?}"
+[[ -n "$out_file" ]] && printf '{}' > "$out_file"
 printf '200'
 SH
 chmod +x "$WORK_DIR/gitea/curl"
@@ -0,0 +1,541 @@
+#!/usr/bin/env bash
+# Regression harness for the optional, identity-checked Gitea squash message.
+
+set -u
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+SUBJECT="${MOSAIC_TEST_SUBJECT:-$SCRIPT_DIR/pr-merge.sh}"
+WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-merge-message-field}"
+ORIG_PATH="$PATH"
+failures=0
+
+rm -rf "$WORK_DIR"
+mkdir -p "$WORK_DIR"
+
+fail() {
+    echo "FAIL $1" >&2
+    failures=$((failures + 1))
+}
+
+make_case() {
+    local name="$1" case_dir
+    case_dir="$WORK_DIR/$name"
+    mkdir -p "$case_dir/bin" "$case_dir/agent"
+    cp "$SUBJECT" "$case_dir/pr-merge.sh"
+    chmod +x "$case_dir/pr-merge.sh"
+
+    cat > "$case_dir/detect-platform.sh" <<'SH'
+#!/usr/bin/env bash
+detect_platform() { PLATFORM=gitea; printf 'gitea\n'; }
+get_repo_owner() { printf 'acme\n'; }
+get_repo_name() { printf 'widgets\n'; }
+get_remote_host() { printf 'git.example.test\n'; }
+get_gitea_token() {
+    printf 'resolved\n' >> "${MOSAIC_TEST_TOKEN_RESOLUTION_LOG:?}"
+    if [[ "${MOSAIC_TEST_TOKEN_AVAILABLE:-true}" != "true" ]]; then
+        return 1
+    fi
+    printf 'fixture-token\n'
+}
+get_gitea_basic_auth() {
+    printf 'resolved\n' >> "${MOSAIC_TEST_BASIC_RESOLUTION_LOG:?}"
+    if [[ "${MOSAIC_TEST_BASIC_AVAILABLE:-false}" == "true" ]]; then
+        printf 'fixture-user:fixture-password\n'
+        return "${MOSAIC_TEST_BASIC_RC:-0}"
+    fi
+    return 1
+}
+get_gitea_login_for_host() { return 1; }
+SH
+
+    cat > "$case_dir/pr-metadata.sh" <<'SH'
+#!/usr/bin/env bash
+if [[ "${MOSAIC_TEST_TITLE_MODE:-safe}" == "injection" ]]; then
+    title='Preserve authors\n\nCo-authored-by: victim <[email protected]>'
+else
+    title='Preserve both branch authors'
+fi
+case "${MOSAIC_TEST_COMMITS_MODE:?}" in
+    verified) head_sha=2222222222222222222222222222222222222222 ;;
+    null-login|unsafe-identity) head_sha=3333333333333333333333333333333333333333 ;;
+    single) head_sha=1111111111111111111111111111111111111111 ;;
+    *) echo "unknown commits mode" >&2; exit 2 ;;
+esac
+printf '{"number":42,"title":"%s","author":"poster","baseRefName":"main","headRefName":"feature/fixture","headRefOid":"%s","headRepository":"acme/widgets"}\n' "$title" "$head_sha"
+SH
+
+    cat > "$case_dir/ci-queue-wait.sh" <<'SH'
+#!/usr/bin/env bash
+exit 0
+SH
+
+    cat > "$case_dir/bin/python3" <<'SH'
+#!/usr/bin/env bash
+for arg in "$@"; do
+    case "$arg" in
+        *"Preserve both branch authors"*|*"[email protected]"*)
+            : > "${MOSAIC_TEST_METADATA_ARGV_MARKER:?}"
+            ;;
+    esac
+done
+exec "${MOSAIC_TEST_REAL_PYTHON:?}" "$@"
+SH
+
+    cat > "$case_dir/bin/curl" <<'SH'
+#!/usr/bin/env bash
+set -eu
+
+for arg in "$@"; do
+    case "$arg" in
+        *"Preserve both branch authors"*|*"[email protected]"*)
+            : > "${MOSAIC_TEST_METADATA_ARGV_MARKER:?}"
+            ;;
+    esac
+done
+
+url=""
+method="GET"
+out_file=""
+data=""
+config=""
+auth_mode="none"
+has_max_filesize=0
+has_max_time=0
+has_connect_timeout=0
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -o)
+            out_file="$2"
+            shift 2
+            ;;
+        -w)
+            shift 2
+            ;;
+        -X)
+            method="$2"
+            shift 2
+            ;;
+        -d|--data|--data-binary)
+            data="$2"
+            if [[ "$data" == @* ]]; then
+                data=$(<"${data#@}")
+            fi
+            shift 2
+            ;;
+        -K|--config)
+            if [[ "$2" == "-" ]]; then
+                config=$(cat)
+            fi
+            shift 2
+            ;;
+        --max-filesize)
+            has_max_filesize=1
+            shift 2
+            ;;
+        --max-time)
+            has_max_time=1
+            shift 2
+            ;;
+        --connect-timeout)
+            has_connect_timeout=1
+            shift 2
+            ;;
+        -H|--header|-u|--user)
+            if [[ "$2" == *"fixture-token"* ]]; then
+                : > "${MOSAIC_TEST_TOKEN_ARGV_MARKER:?}"
+            fi
+            if [[ "$2" == *"fixture-password"* ]]; then
+                : > "${MOSAIC_TEST_BASIC_ARGV_MARKER:?}"
+            fi
+            shift 2
+            ;;
+        http://*|https://*)
+            url="$1"
+            shift
+            ;;
+        *)
+            shift
+            ;;
+    esac
+done
+
+if [[ "$config" == *"Authorization: token fixture-token"* ]]; then
+    auth_mode="token"
+    : > "${MOSAIC_TEST_AUTH_CONFIG_MARKER:?}"
+elif [[ "$config" == *"user = \"fixture-user:fixture-password\""* ]]; then
+    auth_mode="basic"
+    : > "${MOSAIC_TEST_BASIC_CONFIG_MARKER:?}"
+fi
+printf '%s %s %s\n' "$method" "$auth_mode" "$url" >> "${MOSAIC_TEST_CURL_LOG:?}"
+printf '%s:%s:%s\n' "$has_max_filesize" "$has_max_time" "$has_connect_timeout" >> "${MOSAIC_TEST_CURL_BOUNDS_LOG:?}"
+
+case "$url" in
+    */pulls/42)
+        case "${MOSAIC_TEST_COMMITS_MODE:?}" in
+            verified) head_sha=2222222222222222222222222222222222222222 ;;
+            null-login|unsafe-identity) head_sha=3333333333333333333333333333333333333333 ;;
+            single) head_sha=1111111111111111111111111111111111111111 ;;
+            *) echo "unknown commits mode" >&2; exit 2 ;;
+        esac
+        if [[ "${MOSAIC_TEST_HEAD_MODE:-stable}" == "moved" ]]; then
+            head_sha=4444444444444444444444444444444444444444
+        fi
+        body="{\"head\":{\"sha\":\"$head_sha\"}}"
+        code=200
+        if [[ "${MOSAIC_TEST_FALLBACK_MODE:-none}" == "inspection" && "$auth_mode" == "token" ]]; then
+            body='{"message":"token rejected"}'
+            code=401
+        fi
+        ;;
+    */pulls/42/commits*)
+        case "${MOSAIC_TEST_COMMITS_MODE:?}" in
+            verified)
+                if [[ "${MOSAIC_TEST_EMAIL_MODE:-safe}" == "escape" ]]; then
+                    body='[{"sha":"2222222222222222222222222222222222222222","commit":{"author":{"name":"Alice","email":"alice+\u001b[[email protected]"}},"author":{"login":"alice"}},{"sha":"1111111111111111111111111111111111111111","commit":{"author":{"name":"Poster","email":"[email protected]"}},"author":{"login":"poster"}}]'
+                else
+                    body='[{"sha":"2222222222222222222222222222222222222222","commit":{"author":{"name":"Alice","email":"[email protected]"}},"author":{"login":"alice"}},{"sha":"1111111111111111111111111111111111111111","commit":{"author":{"name":"Poster","email":"[email protected]"}},"author":{"login":"poster"}}]'
+                fi
+                ;;
+            null-login)
+                body='[{"sha":"1111111111111111111111111111111111111111","commit":{"author":{"name":"Poster","email":"[email protected]"}},"author":{"login":"poster"}},{"sha":"3333333333333333333333333333333333333333","commit":{"author":{"name":"Unresolved Author","email":"[email protected]\n\u001b[31m"}},"author":null}]'
+                ;;
+            unsafe-identity)
+                body='[{"sha":"unsafe\n\u001b[31m","commit":{"author":{"name":"Unsafe","email":"not-an-email"}},"author":{"login":"unsafe"}},{"sha":"3333333333333333333333333333333333333333","commit":{"author":{"name":"Poster","email":"[email protected]"}},"author":{"login":"poster"}}]'
+                ;;
+            single)
+                body='[{"sha":"1111111111111111111111111111111111111111","commit":{"author":{"name":"Poster","email":"[email protected]"}},"author":{"login":"poster"}}]'
+                ;;
+            *)
+                echo "unknown commits mode" >&2
+                exit 2
+                ;;
+        esac
+        code=200
+        if [[ "${MOSAIC_TEST_FALLBACK_MODE:-none}" == "inspection" && "$auth_mode" == "token" ]]; then
+            body='{"message":"token rejected"}'
+            code=401
+        fi
+        ;;
+    */pulls/42/merge)
+        body='{}'
+        code=200
+        if [[ "${MOSAIC_TEST_FALLBACK_MODE:-none}" == "merge" && "$auth_mode" == "token" ]]; then
+            body='{"message":"token rejected"}'
+            code=401
+        elif [[ "${MOSAIC_TEST_FALLBACK_MODE:-none}" == "provider-error" ]]; then
+            body='{"message":"branch policy rejected\n\u001b[31m"}'
+            code=409
+        elif [[ "${MOSAIC_TEST_FALLBACK_MODE:-none}" == "forbidden" ]]; then
+            body='{"message":"permission denied"}'
+            code=403
+        else
+            printf '%s' "$data" > "${MOSAIC_TEST_MERGE_PAYLOAD:?}"
+        fi
+        ;;
+    */users/*)
+        body='{"message":"not found"}'
+        code=404
+        ;;
+    *)
+        body='{"message":"unexpected URL"}'
+        code=500
+        ;;
+esac
+
+if [[ -n "$out_file" ]]; then
+    printf '%s' "$body" > "$out_file"
+else
+    printf '%s' "$body"
+fi
+printf '%s' "$code"
+case "${MOSAIC_TEST_CURL_FAILURE:-none}" in
+    oversize) exit 63 ;;
+    stalled) exit 28 ;;
+esac
+SH
+
+    chmod +x "$case_dir/detect-platform.sh" "$case_dir/pr-metadata.sh" \
+        "$case_dir/ci-queue-wait.sh" "$case_dir/bin/curl" "$case_dir/bin/python3"
+    printf '%s\n' "$case_dir"
+}
+
+run_case() {
+    local case_dir="$1" mode="$2"
+    shift 2
+    MOSAIC_TEST_COMMITS_MODE="$mode" \
+    MOSAIC_TEST_CURL_LOG="$case_dir/curl.log" \
+    MOSAIC_TEST_CURL_BOUNDS_LOG="$case_dir/curl-bounds.log" \
+    MOSAIC_TEST_MERGE_PAYLOAD="$case_dir/merge-payload.json" \
+    MOSAIC_TEST_TOKEN_ARGV_MARKER="$case_dir/token-in-argv" \
+    MOSAIC_TEST_BASIC_ARGV_MARKER="$case_dir/basic-in-argv" \
+    MOSAIC_TEST_AUTH_CONFIG_MARKER="$case_dir/auth-via-config" \
+    MOSAIC_TEST_BASIC_CONFIG_MARKER="$case_dir/basic-via-config" \
+    MOSAIC_TEST_TOKEN_RESOLUTION_LOG="$case_dir/token-resolution.log" \
+    MOSAIC_TEST_BASIC_RESOLUTION_LOG="$case_dir/basic-resolution.log" \
+    MOSAIC_TEST_METADATA_ARGV_MARKER="$case_dir/metadata-in-argv" \
+    MOSAIC_TEST_REAL_PYTHON="$(command -v python3)" \
+    AGENT_WORK_ROOT="$case_dir/agent" \
+    PATH="$case_dir/bin:$ORIG_PATH" \
+        "$case_dir/pr-merge.sh" -n 42 "$@"
+}
+
+# Verified multi-author path: the non-poster trailer is built from one commit's
+# linked author.login and that same commit's author email. No /users lookup.
+verified_dir=$(make_case verified)
+set +e
+verified_output=$(run_case "$verified_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+verified_rc=$?
+set -e
+if [[ "$verified_rc" -ne 0 ]]; then
+    fail "verified multi-author merge expected rc=0, got rc=$verified_rc: $verified_output"
+elif [[ ! -s "$verified_dir/merge-payload.json" ]]; then
+    fail "verified multi-author merge did not reach the API payload"
+else
+    python3 - "$verified_dir/merge-payload.json" <<'PY' || fail "verified payload did not preserve squash and exact message fields"
+import json
+import sys
+payload = json.load(open(sys.argv[1], encoding="utf-8"))
+assert payload == {
+    "Do": "squash",
+    "head_commit_id": "2222222222222222222222222222222222222222",
+    "MergeTitleField": "Preserve both branch authors",
+    "MergeMessageField": "Co-authored-by: alice <[email protected]>",
+}, payload
+PY
+fi
+[[ -e "$verified_dir/auth-via-config" ]] || fail "verified path did not authenticate curl through stdin config"
+[[ ! -e "$verified_dir/token-in-argv" ]] || fail "verified path placed the Gitea token in curl argv"
+[[ ! -e "$verified_dir/metadata-in-argv" ]] || fail "verified path placed PR title or contributor email in child argv"
+[[ "$(wc -l < "$verified_dir/token-resolution.log")" -eq 1 ]] || fail "verified path did not bind inspection and merge to one credential resolution"
+if grep -q '/users/' "$verified_dir/curl.log" 2>/dev/null; then
+    fail "verified path performed a forbidden second /users lookup"
+fi
+if grep -qv '^1:1:1$' "$verified_dir/curl-bounds.log"; then
+    fail "verified path did not apply size/max-time/connect-time bounds to every provider download"
+fi
+
+# A linked email containing a terminal escape must block before mutation.
+escape_email_dir=$(make_case escape-email)
+set +e
+escape_email_output=$(MOSAIC_TEST_EMAIL_MODE=escape run_case "$escape_email_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+escape_email_rc=$?
+set -e
+[[ "$escape_email_rc" -ne 0 ]] || fail "control-byte email unexpectedly passed"
+[[ "$escape_email_output" == *"unusable linked identity"* ]] || fail "control-byte email refusal lost its diagnostic"
+[[ ! -e "$escape_email_dir/merge-payload.json" ]] || fail "control-byte email reached the merge API"
+
+# Curl transfer and duration failures must remain failures even with HTTP 200.
+for failure_mode in oversize stalled; do
+    failure_dir=$(make_case "curl-$failure_mode")
+    set +e
+    failure_output=$(MOSAIC_TEST_CURL_FAILURE="$failure_mode" run_case "$failure_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+    failure_rc=$?
+    set -e
+    [[ "$failure_rc" -ne 0 ]] || fail "curl $failure_mode failure was discarded: $failure_output"
+    [[ ! -e "$failure_dir/merge-payload.json" ]] || fail "curl $failure_mode failure reached the merge API"
+done
+
+# The authenticated head is re-read under the mutation credential but cannot
+# replace the canonical preflight/review head. A move blocks before enumeration
+# or mutation even though the provider returned a valid new SHA.
+moved_dir=$(make_case moved-head)
+set +e
+moved_output=$(MOSAIC_TEST_HEAD_MODE=moved \
+    run_case "$moved_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+moved_rc=$?
+set -e
+[[ "$moved_rc" -ne 0 ]] || fail "moved authenticated head unexpectedly passed"
+[[ "$moved_output" == *"authenticated PR head moved from reviewed"* ]] || fail "moved head refusal lost its diagnostic"
+[[ "$moved_output" == *"tl-mosaic"* ]] || fail "moved head refusal omitted the named escalation principal"
+[[ ! -e "$moved_dir/merge-payload.json" ]] || fail "moved head refusal reached the merge API"
+moved_sequence=$(awk '{print $1 ":" $2}' "$moved_dir/curl.log" | paste -sd, -)
+[[ "$moved_sequence" == "GET:token" ]] || fail "moved head refusal performed post-move inspection/mutation (calls=$moved_sequence)"
+
+# Token resolution failure is not an authentication response. It must fail
+# closed instead of borrowing a Basic credential under a different principal.
+token_missing_dir=$(make_case token-missing)
+set +e
+token_missing_output=$(MOSAIC_TEST_TOKEN_AVAILABLE=false MOSAIC_TEST_BASIC_AVAILABLE=true \
+    run_case "$token_missing_dir" single 2>&1)
+token_missing_rc=$?
+set -e
+[[ "$token_missing_rc" -ne 0 ]] || fail "missing token unexpectedly borrowed Basic Auth"
+[[ "$token_missing_output" == *"required Gitea token"* ]] || fail "missing token refusal lost its diagnostic"
+[[ ! -e "$token_missing_dir/basic-resolution.log" ]] || fail "missing token resolved Basic Auth after identity failure"
+[[ ! -e "$token_missing_dir/curl.log" ]] || fail "missing token reached a provider request"
+
+# A failed Basic resolver must never use its nonempty output or reach mutation.
+basic_rc_dir=$(make_case basic-resolver-rc)
+set +e
+basic_rc_output=$(MOSAIC_TEST_BASIC_AVAILABLE=true MOSAIC_TEST_BASIC_RC=91 MOSAIC_TEST_FALLBACK_MODE=inspection \
+    run_case "$basic_rc_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+basic_rc_rc=$?
+set -e
+[[ "$basic_rc_rc" -ne 0 ]] || fail "failed Basic resolver output unexpectedly authorized a merge: $basic_rc_output"
+[[ ! -e "$basic_rc_dir/merge-payload.json" ]] || fail "failed Basic resolver reached the merge API"
+
+# HTTP 401 never changes principals: inspection rejection fails closed without
+# resolving or attempting Basic Auth.
+fallback_inspect_dir=$(make_case fallback-inspection)
+set +e
+fallback_inspect_output=$(MOSAIC_TEST_BASIC_AVAILABLE=true MOSAIC_TEST_FALLBACK_MODE=inspection \
+    run_case "$fallback_inspect_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+fallback_inspect_rc=$?
+set -e
+[[ "$fallback_inspect_rc" -ne 0 ]] || fail "inspection token rejection unexpectedly changed principals"
+[[ "$fallback_inspect_output" == *"refusing cross-principal credential fallback"* ]] || fail "inspection token rejection lost its refusal diagnostic"
+[[ ! -e "$fallback_inspect_dir/basic-resolution.log" ]] || fail "inspection token rejection resolved Basic Auth"
+[[ ! -e "$fallback_inspect_dir/merge-payload.json" ]] || fail "inspection token rejection reached merge mutation"
+inspect_sequence=$(awk '{print $1 ":" $2}' "$fallback_inspect_dir/curl.log" | paste -sd, -)
+[[ "$inspect_sequence" == "GET:token" ]] || fail "inspection rejection made unexpected provider calls (calls=$inspect_sequence)"
+
+# Token rejection at merge likewise fails closed without cross-principal retry.
+fallback_merge_dir=$(make_case fallback-merge)
+set +e
+fallback_merge_output=$(MOSAIC_TEST_BASIC_AVAILABLE=true MOSAIC_TEST_FALLBACK_MODE=merge \
+    run_case "$fallback_merge_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+fallback_merge_rc=$?
+set -e
+[[ "$fallback_merge_rc" -ne 0 ]] || fail "merge token rejection unexpectedly changed principals"
+[[ "$fallback_merge_output" == *"refusing cross-principal credential fallback"* ]] || fail "merge token rejection lost its refusal diagnostic"
+[[ ! -e "$fallback_merge_dir/basic-resolution.log" ]] || fail "merge token rejection resolved Basic Auth"
+[[ ! -e "$fallback_merge_dir/merge-payload.json" ]] || fail "merge token rejection recorded a successful payload"
+merge_sequence=$(awk '{print $1 ":" $2}' "$fallback_merge_dir/curl.log" | paste -sd, -)
+[[ "$merge_sequence" == "GET:token,GET:token,POST:token" ]] || fail "merge rejection made unexpected provider calls (calls=$merge_sequence)"
+
+# BLOCK path: a commit email exists but author.login is null. It must name both
+# facts, name the escalation principal, and never reach the merge endpoint.
+null_dir=$(make_case null-login)
+set +e
+null_output=$(run_case "$null_dir" null-login --co-author-trailers --escalate-to tl-mosaic 2>&1)
+null_rc=$?
+set -e
+[[ "$null_rc" -ne 0 ]] || fail "null-login author expected a non-zero BLOCK"
+[[ "$null_output" == *"BLOCK"* ]] || fail "null-login author omitted BLOCK diagnostic"
+[[ "$null_output" == *"author.login=NULL"* ]] || fail "null-login author omitted the null provider fact"
+[[ "$null_output" == *"[email protected]"* ]] || fail "null-login author omitted the commit email fact"
+[[ "$null_output" == *'\n\x1b[31m'* ]] || fail "null-login author diagnostic did not escape control characters"
+[[ "$null_output" != *$'\033'* ]] || fail "null-login author diagnostic emitted a raw terminal escape"
+[[ "$(printf '%s\n' "$null_output" | wc -l)" -eq 1 ]] || fail "null-login author diagnostic permitted newline injection"
+[[ "$null_output" == *"tl-mosaic"* ]] || fail "null-login author omitted the named escalation principal"
+[[ ! -e "$null_dir/merge-payload.json" ]] || fail "null-login BLOCK still reached the merge API"
+
+# Every provider-derived field in alternate BLOCK diagnostics is log-safe too,
+# including an invalid non-head SHA that contains control characters.
+unsafe_dir=$(make_case unsafe-identity)
+set +e
+unsafe_output=$(run_case "$unsafe_dir" unsafe-identity --co-author-trailers --escalate-to tl-mosaic 2>&1)
+unsafe_rc=$?
+set -e
+[[ "$unsafe_rc" -ne 0 ]] || fail "unsafe identity expected a non-zero BLOCK"
+[[ "$unsafe_output" == *"unusable linked identity"* ]] || fail "unsafe identity omitted its BLOCK reason"
+[[ "$unsafe_output" == *'\n\x1b[31m'* ]] || fail "unsafe identity SHA did not escape control characters"
+[[ "$unsafe_output" != *$'\033'* ]] || fail "unsafe identity diagnostic emitted a raw terminal escape"
+[[ "$(printf '%s\n' "$unsafe_output" | wc -l)" -eq 1 ]] || fail "unsafe identity diagnostic permitted newline injection"
+[[ ! -e "$unsafe_dir/merge-payload.json" ]] || fail "unsafe identity BLOCK still reached the merge API"
+
+# The provider PR title cannot add an unchecked trailer outside the constructed
+# message field: multi-line and trailer-shaped titles block before mutation.
+title_dir=$(make_case title-injection)
+set +e
+title_output=$(MOSAIC_TEST_TITLE_MODE=injection \
+    run_case "$title_dir" verified --co-author-trailers --escalate-to tl-mosaic 2>&1)
+title_rc=$?
+set -e
+[[ "$title_rc" -ne 0 ]] || fail "title trailer injection unexpectedly passed"
+[[ "$title_output" == *"not one printable, non-trailer line"* ]] || fail "title injection refusal lost its diagnostic"
+[[ ! -e "$title_dir/merge-payload.json" ]] || fail "title injection reached the merge API"
+
+# Provider failures remain diagnosable after their temporary response file is
+# removed, but provider-controlled control characters stay log-safe.
+error_dir=$(make_case provider-error)
+set +e
+error_output=$(MOSAIC_TEST_BASIC_AVAILABLE=true MOSAIC_TEST_FALLBACK_MODE=provider-error \
+    run_case "$error_dir" single 2>&1)
+error_rc=$?
+set -e
+[[ "$error_rc" -ne 0 ]] || fail "provider error unexpectedly passed"
+[[ "$error_output" == *"HTTP 409"* ]] || fail "provider error omitted the HTTP status"
+[[ "$error_output" == *"branch policy rejected"* ]] || fail "provider error response was discarded"
+[[ "$error_output" == *'\n\x1b[31m'* ]] || fail "provider error response did not escape control characters"
+[[ "$error_output" != *$'\033'* ]] || fail "provider error response emitted a raw terminal escape"
+[[ "$error_output" != *"Basic Auth fallback"* ]] || fail "provider error advertised removed Basic Auth fallback"
+[[ ! -e "$error_dir/basic-resolution.log" ]] || fail "HTTP 409 policy denial incorrectly triggered Basic Auth fallback"
+
+# Authorization denials likewise fail closed instead of changing principals.
+forbidden_dir=$(make_case forbidden)
+set +e
+forbidden_output=$(MOSAIC_TEST_BASIC_AVAILABLE=true MOSAIC_TEST_FALLBACK_MODE=forbidden \
+    run_case "$forbidden_dir" single 2>&1)
+forbidden_rc=$?
+set -e
+[[ "$forbidden_rc" -ne 0 ]] || fail "HTTP 403 authorization denial unexpectedly passed"
+[[ "$forbidden_output" == *"HTTP 403"* ]] || fail "authorization denial omitted the HTTP status"
+[[ "$forbidden_output" != *"Basic Auth fallback"* ]] || fail "authorization denial advertised removed Basic Auth fallback"
+[[ ! -e "$forbidden_dir/basic-resolution.log" ]] || fail "HTTP 403 authorization denial incorrectly triggered Basic Auth fallback"
+
+# The BLOCK destination cannot be generic or inferred after failure: opting in
+# without a named principal is refused before any provider operation.
+principal_dir=$(make_case missing-principal)
+set +e
+principal_output=$(run_case "$principal_dir" verified --co-author-trailers 2>&1)
+principal_rc=$?
+set -e
+[[ "$principal_rc" -ne 0 ]] || fail "co-author mode without a named principal unexpectedly passed"
+[[ "$principal_output" == *"requires --escalate-to with a named principal"* ]] || fail "missing-principal refusal lost its diagnostic"
+[[ ! -e "$principal_dir/merge-payload.json" ]] || fail "missing-principal refusal reached the merge API"
+
+# A trailing value-taking option receives a stable CLI diagnostic instead of a
+# set -u unbound-variable crash.
+value_dir=$(make_case missing-principal-value)
+set +e
+value_output=$(run_case "$value_dir" verified --co-author-trailers --escalate-to 2>&1)
+value_rc=$?
+set -e
+[[ "$value_rc" -ne 0 ]] || fail "missing --escalate-to value unexpectedly passed"
+[[ "$value_output" == *"--escalate-to requires one principal name"* ]] || fail "missing --escalate-to value lost its diagnostic"
+[[ "$value_output" != *"unbound variable"* ]] || fail "missing --escalate-to value crashed under set -u"
+[[ ! -e "$value_dir/merge-payload.json" ]] || fail "missing --escalate-to value reached the merge API"
+
+# Negative control: ordinary single-author merge remains byte-for-byte payload
+# compatible and hardcoded to squash, with no optional message fields.
+single_dir=$(make_case single)
+set +e
+single_output=$(run_case "$single_dir" single 2>&1)
+single_rc=$?
+set -e
+if [[ "$single_rc" -ne 0 ]]; then
+    fail "ordinary single-author merge expected rc=0, got rc=$single_rc: $single_output"
+elif [[ ! -s "$single_dir/merge-payload.json" ]]; then
+    fail "ordinary single-author merge did not reach the API payload"
+else
+    python3 - "$single_dir/merge-payload.json" <<'PY' || fail "ordinary single-author payload changed"
+import json
+import sys
+payload = json.load(open(sys.argv[1], encoding="utf-8"))
+assert payload == {
+    "Do": "squash",
+    "head_commit_id": "1111111111111111111111111111111111111111",
+}, payload
+PY
+fi
+[[ -e "$single_dir/auth-via-config" ]] || fail "ordinary path did not authenticate curl through stdin config"
+[[ ! -e "$single_dir/token-in-argv" ]] || fail "ordinary path placed the Gitea token in curl argv"
+[[ "$(wc -l < "$single_dir/token-resolution.log")" -eq 1 ]] || fail "ordinary path did not use exactly one credential resolution"
+
+# Squash is not defaultable: an explicit non-squash method must remain refused.
+method_dir=$(make_case method-refusal)
+set +e
+method_output=$(run_case "$method_dir" single -m merge 2>&1)
+method_rc=$?
+set -e
+[[ "$method_rc" -ne 0 ]] || fail "non-squash method unexpectedly passed"
+[[ "$method_output" == *"enforces squash merge only"* ]] || fail "non-squash refusal lost its policy diagnostic"
+[[ ! -e "$method_dir/merge-payload.json" ]] || fail "non-squash refusal reached the merge API"
+
+if [[ "$failures" -ne 0 ]]; then
+    echo "pr-merge message-field regression failed ($failures assertions)" >&2
+    exit 1
+fi
+
+echo "pr-merge message-field regression passed (verified, BLOCK, and unchanged squash control)"
@@ -39,7 +39,7 @@ MAX_FRAME: Final = 64 * 1024
 MAX_STATE: Final = 4 * 1024 * 1024
 MAX_PENDING_TOKENS: Final = 256
 MAX_IN_FLIGHT_CONNECTIONS: Final = 16
-MAX_LEASE_TTL_SECONDS: Final = 300
+MAX_LEASE_TTL_SECONDS: Final = 3600
 STATE_VERSION: Final = 1
 READ_DEADLINE_SECONDS: Final = 1.0
 HANDLE_QUEUE_TIMEOUT_SECONDS: Final = 1.0
@@ -50,8 +50,8 @@ LEASE_PENDING: Final = "PENDING_VERIFICATION"
 LEASE_PENDING_PROMOTION: Final = "PENDING_PROMOTION"
 LEASE_VERIFIED: Final = "VERIFIED"
 READ_ONLY_TOOLS: Final = {
-    "claude": frozenset({"Read", "Grep", "Glob", "Ls", "Find"}),
-    "pi": frozenset({"read", "grep", "find", "ls"}),
+    "claude": frozenset({"Read", "Grep", "Glob"}),
+    "pi": frozenset({"read", "ls"}),
 }
 RECOVERY_TOOL: Final = "mosaic_context_recover"

@@ -8,7 +8,9 @@ import json
 import os
 import socket
 import sys
+import time
 from collections.abc import Callable, Mapping, Sequence
+from datetime import datetime, timezone
 from pathlib import Path
 from typing import Final

@@ -53,6 +55,48 @@ def broker_request(socket_path: Path, request: dict[str, object]) -> dict[str, o
    return value


+def _self_starttime() -> str | None:
+    """Field 22 of our own /proc stat — the anchor starttime the broker records.
+
+    Read past the comm field's parens, since a process name may contain them.
+    """
+    try:
+        raw = Path(f"/proc/{os.getpid()}/stat").read_text()
+        return raw.rsplit(")", 1)[1].split()[19]
+    except (OSError, IndexError, ValueError):
+        return None
+
+
+def _append_launch_record(environ: Mapping[str, str], record: dict[str, object]) -> None:
+    """Append one NDJSON event to the #797 Runtime Session Ledger.
+
+    `fleet/run/sessions/` is operator-classified in framework-manifest.txt and is
+    already covered by test-upgrade-manifest-guard.sh, so an upgrade can neither
+    overwrite nor prune it. Files 0600 under a 0700 dir, matching what that guard
+    asserts.
+
+    Never raises: a launch must not be denied over bookkeeping. But it also never
+    fails silently — a missing record is exactly the kind of gap that made the
+    2026-08-06 MUTATOR_UNVERIFIED investigation cost a day.
+    """
+    try:
+        mosaic_home = environ.get("MOSAIC_HOME") or str(Path.home() / ".config" / "mosaic")
+        directory = Path(mosaic_home) / "fleet" / "run" / "sessions"
+        directory.mkdir(parents=True, exist_ok=True)
+        os.chmod(directory, 0o700)
+        framed = {
+            "seq": time.time_ns() // 1_000_000,
+            "ts": datetime.now(timezone.utc).isoformat(),
+            **record,
+        }
+        path = directory / "events.ndjson"
+        descriptor = os.open(path, os.O_WRONLY | os.O_CREAT | os.O_APPEND, 0o600)
+        with os.fdopen(descriptor, "w") as handle:
+            handle.write(json.dumps(framed, separators=(",", ":")) + "\n")
+    except (OSError, ValueError, TypeError) as error:
+        print(f"[mosaic] WARNING: launch record not written: {error}", file=sys.stderr)
+
+
 def main(
    argv: Sequence[str] | None = None,
    *,
@@ -94,8 +138,9 @@ def main(
    # silent pass and never folded into the generic registration-failure
    # branch.
    try:
+        activation_capability = probe_activation_capability(source_environment)
        assert_activation_capability_matches(
-            probe_activation_capability(source_environment),
+            activation_capability,
            expected_activation_capability,
        )
    except VersionCouplingError as version_error:
@@ -128,6 +173,32 @@ def main(
        print("Mosaic lease broker registration failed; runtime launch denied.", file=sys.stderr)
        return 1

+    # Immutable launch record, half two. `mosaic` wrote `session.launch` with the
+    # config/provenance it knows; only this process knows the broker session id
+    # and the activation capability it just asserted. os.execvpe preserves the
+    # PID, so this PID is BOTH the anchor pid and the join key back to that
+    # record. Never fatal — bookkeeping must not deny a launch — but never
+    # silent either.
+    _append_launch_record(
+        source_environment,
+        {
+            "kind": "lease.register",
+            # Joins back to `mosaic`'s session.launch record. NOT pid: execRuntime()
+            # spawns rather than execs, so this process is a CHILD of mosaic with a
+            # different pid. This pid IS the broker anchor pid (os.execvpe below
+            # preserves it), which is a separate and still-useful fact.
+            "launch_id": source_environment.get("MOSAIC_LAUNCH_ID"),
+            "pid": os.getpid(),
+            "runtime": arguments.runtime,
+            "session_id": session_id,
+            "runtime_generation": generation,
+            "generation_file": str(generation_file),
+            "anchor_starttime": _self_starttime(),
+            "activation_capability": activation_capability,
+            "command": Path(command[0]).name,
+        },
+    )
+
    environment = dict(source_environment)
    environment["MOSAIC_LEASE_SESSION_ID"] = session_id
    environment["MOSAIC_RUNTIME_GENERATION"] = str(generation)
@@ -0,0 +1,337 @@
+#!/usr/bin/env python3
+"""Lease promotion client — the half the enforcement toolkit never shipped.
+
+The enforcement half (``daemon.py`` + ``mutator-gate.py``) ships and denies. The
+promotion half has no production caller anywhere in the package: as of 0.0.48,
+0.0.49 and 0.0.50-next.2207, ``begin_verification`` / ``observe_receipt`` /
+``promote_lease`` are invoked only by ``broker-test-client.ts``, the acceptance
+spec, unit tests, and two probes under ``docs/``. Consequence: **no lease on any
+host can reach VERIFIED**, so every mutator is denied ``MUTATOR_UNVERIFIED`` by a
+gate nothing can satisfy.
+
+THE PROTOCOL (``daemon.py:578-754``)
+------------------------------------
+  1. ``begin_verification`` — broker revokes, mints a challenge, and returns the
+     exact ``receipt`` text the MODEL must emit
+  2. *the model emits that text verbatim as its ENTIRE latest message*
+  3. the runtime adapter ships that message to the daemon-owned observer socket
+  4. ``observe_receipt``  -> ``PENDING_PROMOTION``
+  5. ``promote_lease``    -> ``VERIFIED``
+
+THIS MODULE IMPLEMENTS 1, 4 AND 5 — NEVER 2
+-------------------------------------------
+Step 2 is the security property, not a formality. ``is_verbatim_receipt`` uses
+``hmac.compare_digest`` against the exact minted string — explicitly "not a
+transcript substring" (``receipt_challenge.py``). Promotion therefore requires a
+live model that received the challenge in its context and echoed it exactly.
+
+``receipt-observer-client.py`` will post ANY string as the latest assistant
+message. A promotion client that posted its own receipt would satisfy the broker
+while proving nothing — a gate-disabler indistinguishable from a working fix
+unless someone looks for it. **This module never posts a receipt.** Emitting it
+belongs to the runtime adapter, where a real model turn happens.
+
+The construction binds the exact normative source bytes. ``h_source`` /
+``h_payload`` are derived by the framework's own
+``normative_fragments.build_payload`` rather than reimplemented: the broker
+derives them the same way and any divergence yields ``PAYLOAD_BINDING_MISMATCH``.
+There must be exactly one implementation.
+
+WHAT THE BINDING DOES *NOT* PROVE
+---------------------------------
+It is tempting to read a VERIFIED lease as "this agent is running THIS law".
+**It does not mean that**, and writing it down that way is how the belief spread.
+The broker holds no reference copy of any normative source and never opens one;
+it recomputes ``h_source`` / ``h_payload`` from the fragment bytes THIS CLIENT
+sent and compares them to the binding THIS CLIENT sent (``daemon.py:602-616``).
+Both sides of that comparison originate here, so it detects corruption in
+transit and nothing else. What the binding actually asserts is "the client
+claims these bytes, self-consistently".
+
+Making it mean the stronger thing requires the broker to re-read the on-disk
+sources itself, against a manifest the agent cannot rewrite — i.e. broker code
+attestation under its own uid. Until then, do not cite a VERIFIED lease as
+evidence of law integrity.
+
+Usage
+-----
+    lease_promote.py --begin                 # prints the receipt the MODEL must emit
+    lease_promote.py --complete <challenge>  # after the adapter observed it
+"""
+
+from __future__ import annotations
+
+import argparse
+import base64
+import hashlib
+import json
+import os
+import socket
+import sys
+from pathlib import Path
+from typing import Final
+
+# Isolated (`python -I`) adapter invocations must still import co-located
+# framework modules; never depend on the caller's PYTHONPATH.
+_MODULE_DIRECTORY = str(Path(__file__).resolve().parent)
+if _MODULE_DIRECTORY not in sys.path:
+    sys.path.insert(0, _MODULE_DIRECTORY)
+
+from normative_fragments import NormativeFragment, build_payload  # noqa: E402
+
+MAX_FRAME: Final = 64 * 1024
+BROKER_TIMEOUT_SECONDS: Final = 3.0
+SCHEMA_VERSION: Final = 1
+MANIFEST_VERSION: Final = 1
+GENERATOR_VERSION: Final = "mosaic/lease_promote@1"
+DEFAULT_TTL_SECONDS: Final = 3600
+
+# Normative sources whose exact bytes bind the lease, in binding order. Order is
+# load-bearing: ``h_source`` frames the resolved sequence, so reordering changes
+# the derivation. Never fabricate a source that is not on disk.
+FRAGMENT_SOURCES: Final = (
+    "CONSTITUTION.md",
+    "AGENTS.md",
+    "SOUL.md",
+    "USER.md",
+    "STANDARDS.md",
+    "TOOLS.md",
+)
+
+# Framework-owned sources, reconciled on every upgrade — `install.sh:76`
+# FRAMEWORK_OWNED and `config/file-adapter.ts` FRAMEWORK_OWNED_FILES — plus the
+# per-runtime contract shipped under `framework/runtime/<runtime>/`. A deployment
+# missing one of these is broken, not minimal, so their absence is refused rather
+# than silently dropped from the binding.
+#
+# SOUL.md and USER.md are deliberately excluded: install.sh does not seed them
+# ("intentionally NOT seeded here — they are generated by `mosaic init`"), so a
+# fresh install legitimately lacks both. TOOLS.md is user-seeded on first install
+# only. Absence of those three is reported, not fatal.
+REQUIRED_SOURCES: Final = frozenset({"CONSTITUTION.md", "AGENTS.md", "STANDARDS.md"})
+
+
+class IncompleteBinding(RuntimeError):
+    """A source that must bind this lease could not be read.
+
+    **Never downgrade this to a skip.** The broker recomputes the hashes from the
+    fragments it is sent, so an omitted fragment is internally consistent and
+    ``PAYLOAD_BINDING_MISMATCH`` cannot fire — a partial law promotes exactly like
+    a complete one, and nothing downstream can tell the difference. Dropping an
+    unreadable source therefore does not degrade the binding, it forges a smaller
+    one. Fail here, where the omission is still visible.
+    """
+
+
+def mosaic_home() -> Path:
+    return Path(os.environ.get("MOSAIC_HOME") or Path.home() / ".config" / "mosaic")
+
+
+def broker_socket() -> Path:
+    value = os.environ.get("MOSAIC_LEASE_BROKER_SOCKET")
+    if value:
+        return Path(value)
+    runtime_dir = os.environ.get("XDG_RUNTIME_DIR")
+    if runtime_dir:
+        return Path(runtime_dir) / "mosaic-lease" / "broker.sock"
+    return Path(f"/run/user/{os.getuid()}/mosaic-lease/broker.sock")
+
+
+def session_identity() -> tuple[str, int, str]:
+    """Session id, CURRENT generation, runtime.
+
+    The generation file wins over the env var, matching ``lease_generation.py``.
+    Sending a generation HIGHER than the broker's would revoke this session's own
+    authority (``daemon.py:342-344``), so this never guesses.
+    """
+    session_id = os.environ["MOSAIC_LEASE_SESSION_ID"]
+    runtime = os.environ["MOSAIC_LEASE_RUNTIME"]
+    state_file = os.environ.get("MOSAIC_LEASE_GENERATION_FILE")
+    if state_file:
+        try:
+            return session_id, int(Path(state_file).read_text().strip()), runtime
+        except (OSError, ValueError):
+            pass
+    return session_id, int(os.environ["MOSAIC_RUNTIME_GENERATION"]), runtime
+
+
+def build_construction(runtime: str) -> tuple[dict[str, object], object]:
+    """Assemble the wire construction and derive its hashes with the sole builder."""
+    runtime_contract = f"runtime/{runtime}/RUNTIME.md"
+    sources = list(FRAGMENT_SOURCES) + [runtime_contract]
+    required = REQUIRED_SOURCES | {runtime_contract}
+    wire_fragments: list[dict[str, str]] = []
+    objects: list[NormativeFragment] = []
+    absent: list[str] = []
+
+    for source_id in sources:
+        try:
+            content = (mosaic_home() / source_id).read_bytes()
+        except FileNotFoundError:
+            # Genuinely not on disk. Legitimate only for operator-owned sources.
+            if source_id in required:
+                raise IncompleteBinding(
+                    f"required normative source is absent: {source_id}"
+                ) from None
+            absent.append(source_id)
+            continue
+        except OSError as exc:
+            # The path resolves but will not read — EACCES, EIO, EISDIR, ELOOP.
+            # That is an anomaly for EVERY source, optional ones included: an
+            # unreadable file is not an un-configured one, and treating it as
+            # absent is what lets a permission change quietly shrink the law.
+            raise IncompleteBinding(
+                f"normative source is present but unreadable: {source_id} "
+                f"({type(exc).__name__})"
+            ) from exc
+
+        digest = hashlib.sha256(content).hexdigest()
+        wire_fragments.append(
+            {
+                "source_id": source_id,
+                "content_base64": base64.b64encode(content).decode("ascii"),
+                "expected_sha256": digest,
+            }
+        )
+        objects.append(NormativeFragment(source_id, content, digest))
+
+    if not wire_fragments:
+        raise IncompleteBinding("no normative sources found — refusing an empty binding")
+
+    # Absence is legitimate here but never invisible. The omission is already
+    # baked into h_source (the framed source sequence differs), but nothing
+    # compares h_source to an expected value, so this line is the only place a
+    # human learns the binding was narrower than the full set.
+    if absent:
+        print(
+            f"lease_promote: binding omits absent operator sources: {', '.join(absent)}",
+            file=sys.stderr,
+        )
+
+    result = build_payload(
+        manifest_version=MANIFEST_VERSION,
+        generator_version=GENERATOR_VERSION,
+        fragments=objects,
+    )
+    if result.injectionDecision != "ACCEPTED" or not result.promotion:
+        raise RuntimeError(f"construction refused locally: {result.source_reason}")
+
+    return (
+        {
+            "manifest_version": MANIFEST_VERSION,
+            "generator_version": GENERATOR_VERSION,
+            "fragments": wire_fragments,
+        },
+        result,
+    )
+
+
+def broker_request(payload: dict[str, object]) -> dict[str, object]:
+    raw = (json.dumps(payload, separators=(",", ":")) + "\n").encode()
+    if len(raw) > MAX_FRAME:
+        raise ValueError(
+            f"request too large ({len(raw)} bytes); broker frame cap is {MAX_FRAME}"
+        )
+    response = bytearray()
+    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as connection:
+        connection.settimeout(BROKER_TIMEOUT_SECONDS)
+        connection.connect(str(broker_socket()))
+        connection.sendall(raw)
+        connection.shutdown(socket.SHUT_WR)
+        while len(response) <= MAX_FRAME:
+            chunk = connection.recv(4096)
+            if not chunk:
+                break
+            response.extend(chunk)
+    if len(response) > MAX_FRAME or not response.endswith(b"\n"):
+        raise ValueError("invalid broker reply")
+    value = json.loads(response)
+    if not isinstance(value, dict):
+        raise ValueError("invalid broker reply")
+    return value
+
+
+def begin(
+    ttl_seconds: int = DEFAULT_TTL_SECONDS,
+    compaction_epoch: int = 0,
+    request_epoch: int = 0,
+) -> dict[str, object]:
+    """Step 1. Returns the broker reply, including the exact ``receipt`` text."""
+    session_id, generation, runtime = session_identity()
+    construction, derived = build_construction(runtime)
+    return broker_request(
+        {
+            "action": "begin_verification",
+            "session_id": session_id,
+            "runtime_generation": generation,
+            "runtime": runtime,
+            "ttl_seconds": ttl_seconds,
+            "binding": {
+                "compaction_epoch": compaction_epoch,
+                "request_epoch": request_epoch,
+                "h_source": derived.h_source,
+                "h_payload": derived.h_payload,
+                "schema_version": SCHEMA_VERSION,
+            },
+            "construction": construction,
+        }
+    )
+
+
+def complete(challenge: str) -> dict[str, object]:
+    """Steps 4-5. Assumes the model already emitted the receipt and the adapter
+    shipped it to the observer socket."""
+    session_id, generation, _ = session_identity()
+    observed = broker_request(
+        {
+            "action": "observe_receipt",
+            "session_id": session_id,
+            "runtime_generation": generation,
+            "receipt_challenge": challenge,
+        }
+    )
+    if observed.get("ok") is not True or observed.get("state") != "PENDING_PROMOTION":
+        return {"stage": "observe_receipt", **observed}
+    promoted = broker_request(
+        {
+            "action": "promote_lease",
+            "session_id": session_id,
+            "runtime_generation": generation,
+            "receipt_challenge": challenge,
+        }
+    )
+    return {"stage": "promote_lease", **promoted}
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description="Mosaic lease promotion client.")
+    group = parser.add_mutually_exclusive_group(required=True)
+    group.add_argument(
+        "--begin",
+        action="store_true",
+        help="mint a challenge; prints the receipt the MODEL must emit verbatim",
+    )
+    group.add_argument(
+        "--complete",
+        metavar="CHALLENGE",
+        help="observe the emitted receipt and promote the lease",
+    )
+    parser.add_argument("--ttl-seconds", type=int, default=DEFAULT_TTL_SECONDS)
+    arguments = parser.parse_args(argv)
+
+    try:
+        if arguments.begin:
+            print(json.dumps(begin(ttl_seconds=arguments.ttl_seconds), indent=2))
+        else:
+            print(json.dumps(complete(arguments.complete), indent=2))
+    except KeyError as exc:
+        print(f"missing lease environment: {exc}; not a lease-gated session", file=sys.stderr)
+        return 2
+    except (OSError, ValueError, RuntimeError, json.JSONDecodeError) as exc:
+        print(f"{type(exc).__name__}: {exc}", file=sys.stderr)
+        return 2
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
@@ -0,0 +1,333 @@
+#!/usr/bin/env python3
+"""Claude UserPromptSubmit hook for operator-triggered lease promotion."""
+
+from __future__ import annotations
+
+import fcntl
+import json
+import os
+import secrets
+import stat
+import subprocess
+import sys
+import time
+from collections.abc import Callable, Mapping
+from pathlib import Path
+from typing import Final, TextIO
+
+_MODULE_DIRECTORY = str(Path(__file__).resolve().parent)
+if _MODULE_DIRECTORY not in sys.path:
+    sys.path.insert(0, _MODULE_DIRECTORY)
+
+from receipt_challenge import receipt_for  # noqa: E402
+
+MAX_FRAME: Final = 64 * 1024
+PENDING_MAX_AGE_SECONDS: Final = 60 * 60
+PROMOTER_TIMEOUT_SECONDS: Final = 10.0
+PROMOTION_PROMPT: Final = "/mosaic-promote"
+PROMOTER: Final = Path(__file__).resolve().with_name("lease_promote.py")
+PENDING_DIRECTORY: Final = "mosaic-lease"
+LOCK_FILE: Final = "promotion.lock"
+EXPECTED_BEGIN_KEYS: Final = frozenset(
+    {"ok", "state", "receipt_challenge", "receipt", "binding"}
+)
+EXPECTED_BINDING_KEYS: Final = frozenset(
+    {
+        "compaction_epoch",
+        "request_epoch",
+        "h_source",
+        "h_payload",
+        "runtime_generation",
+        "schema_version",
+    }
+)
+
+
+class PromotionAlreadyInProgress(RuntimeError):
+    pass
+
+
+def reject_duplicate_json_keys(pairs: list[tuple[str, object]]) -> dict[str, object]:
+    value: dict[str, object] = {}
+    for key, item in pairs:
+        if key in value:
+            raise ValueError("duplicate promoter JSON key")
+        value[key] = item
+    return value
+
+
+def read_hook_input(stream: object) -> dict[str, object]:
+    raw = getattr(stream, "buffer", stream).read(MAX_FRAME + 1)
+    if not isinstance(raw, bytes) or len(raw) > MAX_FRAME:
+        raise ValueError("invalid UserPromptSubmit input")
+    value = json.loads(raw, object_pairs_hook=reject_duplicate_json_keys)
+    if not isinstance(value, dict):
+        raise ValueError("invalid UserPromptSubmit input")
+    return value
+
+
+def emit_context(stream: TextIO, message: str) -> None:
+    json.dump(
+        {
+            "hookSpecificOutput": {
+                "hookEventName": "UserPromptSubmit",
+                "additionalContext": message,
+            }
+        },
+        stream,
+        separators=(",", ":"),
+    )
+    stream.write("\n")
+
+
+def session_pending_name(environ: Mapping[str, str]) -> tuple[Path, str]:
+    runtime_dir = Path(environ["XDG_RUNTIME_DIR"])
+    session_id = environ["MOSAIC_LEASE_SESSION_ID"]
+    if not runtime_dir.is_absolute():
+        raise ValueError("XDG_RUNTIME_DIR must be absolute")
+    if len(session_id) != 64 or any(character not in "0123456789abcdef" for character in session_id):
+        raise ValueError("invalid lease session id")
+    return runtime_dir, f"pending-{session_id}"
+
+
+def open_pending_directory(runtime_dir: Path) -> int:
+    directory_flags = (
+        os.O_RDONLY
+        | getattr(os, "O_CLOEXEC", 0)
+        | getattr(os, "O_DIRECTORY", 0)
+        | getattr(os, "O_NOFOLLOW", 0)
+    )
+    runtime_descriptor = os.open(runtime_dir, directory_flags)
+    try:
+        runtime_metadata = os.fstat(runtime_descriptor)
+        if (
+            not stat.S_ISDIR(runtime_metadata.st_mode)
+            or runtime_metadata.st_uid != os.getuid()
+            or stat.S_IMODE(runtime_metadata.st_mode) != 0o700
+        ):
+            raise ValueError("unsafe XDG runtime directory")
+        try:
+            os.mkdir(PENDING_DIRECTORY, mode=0o700, dir_fd=runtime_descriptor)
+        except FileExistsError:
+            pass
+        descriptor = os.open(PENDING_DIRECTORY, directory_flags, dir_fd=runtime_descriptor)
+    finally:
+        os.close(runtime_descriptor)
+
+    metadata = os.fstat(descriptor)
+    if (
+        not stat.S_ISDIR(metadata.st_mode)
+        or metadata.st_uid != os.getuid()
+        or stat.S_IMODE(metadata.st_mode) != 0o700
+    ):
+        os.close(descriptor)
+        raise ValueError("unsafe promotion pending directory")
+    return descriptor
+
+
+def acquire_lock(directory_descriptor: int) -> int:
+    flags = (
+        os.O_RDWR
+        | os.O_CREAT
+        | getattr(os, "O_CLOEXEC", 0)
+        | getattr(os, "O_NOFOLLOW", 0)
+    )
+    descriptor = os.open(LOCK_FILE, flags, 0o600, dir_fd=directory_descriptor)
+    metadata = os.fstat(descriptor)
+    if (
+        not stat.S_ISREG(metadata.st_mode)
+        or metadata.st_uid != os.getuid()
+        or stat.S_IMODE(metadata.st_mode) != 0o600
+    ):
+        os.close(descriptor)
+        raise ValueError("unsafe promotion lock file")
+    try:
+        fcntl.flock(descriptor, fcntl.LOCK_EX | fcntl.LOCK_NB)
+    except BlockingIOError as error:
+        os.close(descriptor)
+        raise PromotionAlreadyInProgress() from error
+    return descriptor
+
+
+def sweep_stale_pending(directory_descriptor: int, current_time: float) -> None:
+    cutoff = current_time - PENDING_MAX_AGE_SECONDS
+    removed = False
+    with os.scandir(directory_descriptor) as entries:
+        for candidate in entries:
+            if not (
+                candidate.name.startswith("pending-")
+                or candidate.name.startswith(".pending-")
+            ):
+                continue
+            try:
+                metadata = candidate.stat(follow_symlinks=False)
+                if metadata.st_mtime < cutoff and not stat.S_ISDIR(metadata.st_mode):
+                    os.unlink(candidate.name, dir_fd=directory_descriptor)
+                    removed = True
+            except FileNotFoundError:
+                continue
+    if removed:
+        os.fsync(directory_descriptor)
+
+
+def write_pending(directory_descriptor: int, name: str, challenge: str) -> None:
+    temporary = f".{name}.tmp-{secrets.token_hex(8)}"
+    flags = (
+        os.O_WRONLY
+        | os.O_CREAT
+        | os.O_EXCL
+        | getattr(os, "O_CLOEXEC", 0)
+        | getattr(os, "O_NOFOLLOW", 0)
+    )
+    descriptor = os.open(temporary, flags, 0o600, dir_fd=directory_descriptor)
+    try:
+        os.fchmod(descriptor, 0o600)
+        with os.fdopen(descriptor, "w", encoding="utf-8", closefd=False) as stream:
+            stream.write(challenge)
+            stream.flush()
+            os.fsync(stream.fileno())
+        os.replace(
+            temporary,
+            name,
+            src_dir_fd=directory_descriptor,
+            dst_dir_fd=directory_descriptor,
+        )
+        os.fsync(directory_descriptor)
+    except Exception:
+        try:
+            os.unlink(temporary, dir_fd=directory_descriptor)
+        except FileNotFoundError:
+            pass
+        raise
+    finally:
+        os.close(descriptor)
+
+
+def parse_begin_reply(
+    completed: subprocess.CompletedProcess[str],
+) -> tuple[str, dict[str, object] | None]:
+    if completed.returncode != 0:
+        return f"PROMOTER_EXIT_{completed.returncode}", None
+    try:
+        value = json.loads(
+            completed.stdout,
+            object_pairs_hook=reject_duplicate_json_keys,
+        )
+    except (json.JSONDecodeError, RecursionError, TypeError, ValueError):
+        return "INVALID_PROMOTER_REPLY", None
+    if not isinstance(value, dict):
+        return "INVALID_PROMOTER_REPLY", None
+    if value.get("ok") is False and set(value) == {"ok", "code"}:
+        code = value.get("code")
+        return code if isinstance(code, str) and code else "PROMOTION_BEGIN_REFUSED", value
+    if set(value) != EXPECTED_BEGIN_KEYS or value.get("ok") is not True:
+        return "INVALID_PROMOTER_REPLY", None
+    if value.get("state") != "PENDING_VERIFICATION":
+        return "INVALID_PROMOTER_REPLY", None
+    challenge = value.get("receipt_challenge")
+    receipt = value.get("receipt")
+    binding = value.get("binding")
+    if (
+        not isinstance(challenge, str)
+        or len(challenge) != 64
+        or any(character not in "0123456789abcdef" for character in challenge)
+        or not isinstance(receipt, str)
+        or not isinstance(binding, dict)
+        or set(binding) != EXPECTED_BINDING_KEYS
+    ):
+        return "INVALID_PROMOTER_REPLY", None
+    integer_fields = (
+        "compaction_epoch",
+        "request_epoch",
+        "runtime_generation",
+        "schema_version",
+    )
+    if any(type(binding.get(field)) is not int or binding[field] < 0 for field in integer_fields):
+        return "INVALID_PROMOTER_REPLY", None
+    if not all(
+        isinstance(binding.get(field), str)
+        and len(binding[field]) == 64
+        and all(character in "0123456789abcdef" for character in binding[field])
+        for field in ("h_source", "h_payload")
+    ):
+        return "INVALID_PROMOTER_REPLY", None
+    if not secrets.compare_digest(
+        receipt.encode("utf-8"),
+        receipt_for(challenge, binding).encode("utf-8"),
+    ):
+        return "INVALID_PROMOTER_REPLY", None
+    return "", value
+
+
+def main(
+    *,
+    environ: Mapping[str, str] | None = None,
+    stdin: object | None = None,
+    stdout: TextIO | None = None,
+    stderr: TextIO | None = None,
+    run: Callable[..., subprocess.CompletedProcess[str]] = subprocess.run,
+    now: Callable[[], float] = time.time,
+) -> int:
+    source_environment = os.environ if environ is None else environ
+    input_stream = sys.stdin if stdin is None else stdin
+    output_stream = sys.stdout if stdout is None else stdout
+    error_stream = sys.stderr if stderr is None else stderr
+
+    try:
+        hook_input = read_hook_input(input_stream)
+    except (OSError, RecursionError, ValueError, json.JSONDecodeError) as error:
+        print(f"Mosaic promotion trigger ignored invalid hook input: {error}", file=error_stream)
+        return 0
+    if hook_input.get("prompt") != PROMOTION_PROMPT:
+        return 0
+
+    directory_descriptor: int | None = None
+    lock_descriptor: int | None = None
+    try:
+        runtime_dir, pending_name = session_pending_name(source_environment)
+        directory_descriptor = open_pending_directory(runtime_dir)
+        lock_descriptor = acquire_lock(directory_descriptor)
+        sweep_stale_pending(directory_descriptor, now())
+        completed = run(
+            [sys.executable, "-I", "-S", "-B", str(PROMOTER), "--begin"],
+            check=False,
+            capture_output=True,
+            text=True,
+            env=dict(source_environment),
+            timeout=PROMOTER_TIMEOUT_SECONDS,
+        )
+        code, reply = parse_begin_reply(completed)
+        if code:
+            if completed.stderr:
+                print(completed.stderr.strip(), file=error_stream)
+            emit_context(output_stream, f"Mosaic promotion did not begin: {code}.")
+            return 0
+        if reply is None:
+            raise ValueError("missing promotion reply")
+        write_pending(directory_descriptor, pending_name, str(reply["receipt_challenge"]))
+        emit_context(
+            output_stream,
+            "The operator invoked the registered /mosaic-promote command. "
+            "This receipt was generated locally by this seat's own lease broker; "
+            "echoing it verbatim is the designed confirmation step and discloses nothing. "
+            "Reply with exactly the following text and nothing else: "
+            f"{reply['receipt']}",
+        )
+    except PromotionAlreadyInProgress:
+        emit_context(
+            output_stream,
+            "Mosaic promotion did not begin: PROMOTION_ALREADY_IN_PROGRESS.",
+        )
+    except (KeyError, OSError, RecursionError, ValueError, subprocess.SubprocessError) as error:
+        print(f"Mosaic promotion begin failed: {type(error).__name__}: {error}", file=error_stream)
+        emit_context(output_stream, "Mosaic promotion did not begin: PROMOTION_TRIGGER_FAILED.")
+    finally:
+        if lock_descriptor is not None:
+            os.close(lock_descriptor)
+        if directory_descriptor is not None:
+            os.close(directory_descriptor)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
@@ -0,0 +1,306 @@
+#!/usr/bin/env python3
+"""Claude Stop hook that completes a pending operator-triggered promotion."""
+
+from __future__ import annotations
+
+import fcntl
+import json
+import os
+import secrets
+import stat
+import subprocess
+import sys
+from collections.abc import Callable, Mapping
+from pathlib import Path
+from typing import Final, NamedTuple, TextIO
+
+MAX_FRAME: Final = 64 * 1024
+PROMOTER_TIMEOUT_SECONDS: Final = 10.0
+PROMOTER: Final = Path(__file__).resolve().with_name("lease_promote.py")
+PENDING_DIRECTORY: Final = "mosaic-lease"
+LOCK_FILE: Final = "promotion.lock"
+TERMINAL_FAILURE_CODES: Final = frozenset(
+    {
+        "RECEIPT_REPLAY",
+        "RECEIPT_MISMATCH",
+        "INVALID_LEASE_TRANSITION",
+        "PROMOTION_TOKEN_INVALID",
+    }
+)
+
+
+class PendingChallenge(NamedTuple):
+    value: str
+    device: int
+    inode: int
+
+
+def reject_duplicate_json_keys(pairs: list[tuple[str, object]]) -> dict[str, object]:
+    value: dict[str, object] = {}
+    for key, item in pairs:
+        if key in value:
+            raise ValueError("duplicate promoter JSON key")
+        value[key] = item
+    return value
+
+
+def session_pending_name(environ: Mapping[str, str]) -> tuple[Path, str]:
+    runtime_dir = Path(environ["XDG_RUNTIME_DIR"])
+    session_id = environ["MOSAIC_LEASE_SESSION_ID"]
+    if not runtime_dir.is_absolute():
+        raise ValueError("XDG_RUNTIME_DIR must be absolute")
+    if len(session_id) != 64 or any(character not in "0123456789abcdef" for character in session_id):
+        raise ValueError("invalid lease session id")
+    return runtime_dir, f"pending-{session_id}"
+
+
+def open_pending_directory(runtime_dir: Path) -> int | None:
+    directory_flags = (
+        os.O_RDONLY
+        | getattr(os, "O_CLOEXEC", 0)
+        | getattr(os, "O_DIRECTORY", 0)
+        | getattr(os, "O_NOFOLLOW", 0)
+    )
+    try:
+        runtime_descriptor = os.open(runtime_dir, directory_flags)
+    except FileNotFoundError:
+        return None
+    try:
+        runtime_metadata = os.fstat(runtime_descriptor)
+        if (
+            not stat.S_ISDIR(runtime_metadata.st_mode)
+            or runtime_metadata.st_uid != os.getuid()
+            or stat.S_IMODE(runtime_metadata.st_mode) != 0o700
+        ):
+            raise ValueError("unsafe XDG runtime directory")
+        try:
+            descriptor = os.open(PENDING_DIRECTORY, directory_flags, dir_fd=runtime_descriptor)
+        except FileNotFoundError:
+            return None
+    finally:
+        os.close(runtime_descriptor)
+
+    metadata = os.fstat(descriptor)
+    if (
+        not stat.S_ISDIR(metadata.st_mode)
+        or metadata.st_uid != os.getuid()
+        or stat.S_IMODE(metadata.st_mode) != 0o700
+    ):
+        os.close(descriptor)
+        raise ValueError("unsafe promotion pending directory")
+    return descriptor
+
+
+def acquire_lock(directory_descriptor: int) -> int:
+    flags = (
+        os.O_RDWR
+        | os.O_CREAT
+        | getattr(os, "O_CLOEXEC", 0)
+        | getattr(os, "O_NOFOLLOW", 0)
+    )
+    descriptor = os.open(LOCK_FILE, flags, 0o600, dir_fd=directory_descriptor)
+    metadata = os.fstat(descriptor)
+    if (
+        not stat.S_ISREG(metadata.st_mode)
+        or metadata.st_uid != os.getuid()
+        or stat.S_IMODE(metadata.st_mode) != 0o600
+    ):
+        os.close(descriptor)
+        raise ValueError("unsafe promotion lock file")
+    try:
+        fcntl.flock(descriptor, fcntl.LOCK_EX | fcntl.LOCK_NB)
+    except BlockingIOError:
+        os.close(descriptor)
+        raise
+    return descriptor
+
+
+def read_pending(directory_descriptor: int, name: str) -> PendingChallenge | None:
+    flags = os.O_RDONLY | getattr(os, "O_CLOEXEC", 0) | getattr(os, "O_NOFOLLOW", 0)
+    try:
+        descriptor = os.open(name, flags, dir_fd=directory_descriptor)
+    except FileNotFoundError:
+        return None
+    try:
+        metadata = os.fstat(descriptor)
+        if (
+            not stat.S_ISREG(metadata.st_mode)
+            or metadata.st_uid != os.getuid()
+            or stat.S_IMODE(metadata.st_mode) != 0o600
+            or metadata.st_size <= 0
+            or metadata.st_size > MAX_FRAME
+        ):
+            raise ValueError("unsafe promotion pending file")
+        raw = os.read(descriptor, MAX_FRAME + 1)
+    finally:
+        os.close(descriptor)
+    if len(raw) > MAX_FRAME:
+        raise ValueError("oversized promotion challenge")
+    challenge = raw.decode("utf-8")
+    if (
+        len(challenge) != 64
+        or any(character not in "0123456789abcdef" for character in challenge)
+    ):
+        raise ValueError("invalid promotion challenge")
+    return PendingChallenge(challenge, metadata.st_dev, metadata.st_ino)
+
+
+def delete_pending_if_unchanged(
+    directory_descriptor: int,
+    name: str,
+    pending: PendingChallenge,
+    error_stream: TextIO,
+) -> None:
+    quarantine = f".{name}.delete-{secrets.token_hex(8)}"
+    try:
+        os.rename(
+            name,
+            quarantine,
+            src_dir_fd=directory_descriptor,
+            dst_dir_fd=directory_descriptor,
+        )
+    except FileNotFoundError:
+        return
+    except OSError as error:
+        print(f"Mosaic promotion could not quarantine pending file: {error}", file=error_stream)
+        return
+
+    try:
+        moved = os.stat(
+            quarantine,
+            dir_fd=directory_descriptor,
+            follow_symlinks=False,
+        )
+        if (moved.st_dev, moved.st_ino) == (pending.device, pending.inode):
+            os.unlink(quarantine, dir_fd=directory_descriptor)
+            os.fsync(directory_descriptor)
+            return
+
+        print("Mosaic promotion pending file changed; preserving replacement.", file=error_stream)
+        try:
+            os.link(
+                quarantine,
+                name,
+                src_dir_fd=directory_descriptor,
+                dst_dir_fd=directory_descriptor,
+                follow_symlinks=False,
+            )
+        except FileExistsError:
+            print(
+                f"Mosaic promotion preserved replacement as {quarantine}.",
+                file=error_stream,
+            )
+        else:
+            os.unlink(quarantine, dir_fd=directory_descriptor)
+        os.fsync(directory_descriptor)
+    except OSError as error:
+        print(f"Mosaic promotion could not resolve pending file: {error}", file=error_stream)
+
+
+def parse_reply(completed: subprocess.CompletedProcess[str]) -> dict[str, object] | None:
+    if completed.returncode != 0:
+        return None
+    try:
+        value = json.loads(
+            completed.stdout,
+            object_pairs_hook=reject_duplicate_json_keys,
+        )
+    except (json.JSONDecodeError, RecursionError, TypeError, ValueError):
+        return None
+    if not isinstance(value, dict):
+        return None
+    if set(value) == {"stage", "ok", "state"}:
+        if (
+            value.get("stage") == "promote_lease"
+            and value.get("ok") is True
+            and value.get("state") == "VERIFIED"
+        ):
+            return value
+        return None
+    if set(value) == {"stage", "ok", "code"}:
+        if (
+            value.get("stage") in {"observe_receipt", "promote_lease"}
+            and value.get("ok") is False
+            and isinstance(value.get("code"), str)
+            and value.get("code")
+        ):
+            return value
+    return None
+
+
+def main(
+    *,
+    environ: Mapping[str, str] | None = None,
+    stderr: TextIO | None = None,
+    run: Callable[..., subprocess.CompletedProcess[str]] = subprocess.run,
+) -> int:
+    source_environment = os.environ if environ is None else environ
+    error_stream = sys.stderr if stderr is None else stderr
+    directory_descriptor: int | None = None
+    lock_descriptor: int | None = None
+
+    try:
+        runtime_dir, pending_name = session_pending_name(source_environment)
+        directory_descriptor = open_pending_directory(runtime_dir)
+        if directory_descriptor is None:
+            return 0
+        try:
+            lock_descriptor = acquire_lock(directory_descriptor)
+        except (BlockingIOError, FileNotFoundError):
+            print("Mosaic promotion completion deferred: promotion is in progress.", file=error_stream)
+            return 0
+        pending = read_pending(directory_descriptor, pending_name)
+        if pending is None:
+            return 0
+        completed = run(
+            [
+                sys.executable,
+                "-I",
+                "-S",
+                "-B",
+                str(PROMOTER),
+                "--complete",
+                pending.value,
+            ],
+            check=False,
+            capture_output=True,
+            text=True,
+            env=dict(source_environment),
+            timeout=PROMOTER_TIMEOUT_SECONDS,
+        )
+        reply = parse_reply(completed)
+        if reply is not None and reply.get("ok") is True:
+            delete_pending_if_unchanged(
+                directory_descriptor,
+                pending_name,
+                pending,
+                error_stream,
+            )
+            print("Mosaic lease promotion completed.", file=error_stream)
+            return 0
+
+        if reply is not None:
+            code = str(reply["code"])
+            print(f"Mosaic promotion incomplete: {code}.", file=error_stream)
+            if code in TERMINAL_FAILURE_CODES:
+                delete_pending_if_unchanged(
+                    directory_descriptor,
+                    pending_name,
+                    pending,
+                    error_stream,
+                )
+        else:
+            diagnostic = completed.stderr.strip() or f"promoter exit {completed.returncode}"
+            print(f"Mosaic promotion retryable failure: {diagnostic}.", file=error_stream)
+    except (KeyError, OSError, RecursionError, UnicodeError, ValueError, subprocess.SubprocessError) as error:
+        print(f"Mosaic promotion completion deferred: {type(error).__name__}: {error}", file=error_stream)
+    finally:
+        if lock_descriptor is not None:
+            os.close(lock_descriptor)
+        if directory_descriptor is not None:
+            os.close(directory_descriptor)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
@@ -22,13 +22,23 @@ from typing import Final
 MAX_FRAME: Final = 64 * 1024
 BROKER_TIMEOUT_SECONDS: Final = 1.5
 MAX_TRANSCRIPT_BYTES: Final = 4 * 1024 * 1024
+BENIGN_OBSERVATION_UNAVAILABLE_CODE: Final = "OBSERVATION_UNAVAILABLE"
+
+
+def reject_duplicate_json_keys(pairs: list[tuple[str, object]]) -> dict[str, object]:
+    value: dict[str, object] = {}
+    for key, item in pairs:
+        if key in value:
+            raise ValueError("duplicate observer JSON key")
+        value[key] = item
+    return value


 def read_json(stream: object) -> dict[str, object]:
    raw = getattr(stream, "buffer", stream).read(MAX_FRAME + 1)
    if not isinstance(raw, bytes) or len(raw) > MAX_FRAME:
        raise ValueError("invalid observer input")
-    value = json.loads(raw)
+    value = json.loads(raw, object_pairs_hook=reject_duplicate_json_keys)
    if not isinstance(value, dict):
        raise ValueError("invalid observer input")
    return value
@@ -100,9 +110,9 @@ def observer_request(socket_path: Path, request: dict[str, object]) -> dict[str,
            if not chunk:
                break
            response.extend(chunk)
-    if len(response) > MAX_FRAME or not response.endswith(b"\n"):
+    if len(response) > MAX_FRAME or response.count(b"\n") != 1 or not response.endswith(b"\n"):
        raise ValueError("invalid observer reply")
-    value = json.loads(response)
+    value = json.loads(response[:-1], object_pairs_hook=reject_duplicate_json_keys)
    if not isinstance(value, dict):
        raise ValueError("invalid observer reply")
    return value
@@ -119,7 +129,12 @@ def main(argv: Sequence[str] | None = None, *, environ: Mapping[str, str] | None
        if arguments.runtime == "claude":
            if not arguments.latest_entry:
                raise ValueError("Claude observer requires --latest-entry")
-            message = claude_latest_entry(source)
+            if "last_assistant_message" in source:
+                message = source["last_assistant_message"]
+                if not isinstance(message, str):
+                    raise ValueError("invalid Claude observer input")
+            else:
+                message = claude_latest_entry(source)
        else:
            if arguments.latest_entry:
                raise ValueError("Pi observer is message_end only")
@@ -133,10 +148,18 @@ def main(argv: Sequence[str] | None = None, *, environ: Mapping[str, str] | None
            "runtime": arguments.runtime,
            "latest_assistant_message": message,
        })
-    except (KeyError, OSError, ValueError, json.JSONDecodeError) as error:
+    except (KeyError, OSError, RecursionError, ValueError, json.JSONDecodeError) as error:
        print(f"Mosaic receipt observer refused: {error}", file=sys.stderr)
        return 2
-    return 0 if reply == {"ok": True} else 2
+    if set(reply) == {"ok"} and reply.get("ok") is True:
+        return 0
+    if (
+        set(reply) == {"ok", "code"}
+        and reply.get("ok") is False
+        and reply.get("code") == BENIGN_OBSERVATION_UNAVAILABLE_CODE
+    ):
+        return 0
+    return 2


 if __name__ == "__main__":
@@ -33,7 +33,7 @@ def is_verbatim_receipt(message: str, challenge: str, binding: dict[str, object]
    """Require the exact one current-cycle receipt, not a transcript substring."""

    expected = receipt_for(challenge, binding)
-    return hmac.compare_digest(message, expected)
+    return hmac.compare_digest(message.encode("utf-8"), expected.encode("utf-8"))


 def latest_assistant_digest(message: str) -> str:
@@ -25,7 +25,7 @@
    "lint": "eslint src",
    "typecheck": "tsc --noEmit",
    "test": "vitest run --passWithNoTests && pnpm run test:framework-shell",
-    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh"
+    "test:framework-shell": "bash framework/tools/quality/scripts/check-test-enumeration.sh && bash framework/tools/quality/scripts/test-check-test-enumeration.sh && python3 src/lease-broker/daemon_deadline_unittest.py && python3 src/lease-broker/normative_fragments_unittest.py && python3 src/lease-broker/promotion_binding_unittest.py && python3 src/lease-broker/promotion_trigger_unittest.py && python3 src/lease-broker/receipt_challenge_unittest.py && python3 src/lease-broker/context_recovery_unittest.py && python3 src/lease-broker/recovery_runtime_unittest.py && python3 src/lease-broker/recovery_b1_adversarial_unittest.py && python3 src/lease-broker/receipt_observer_client_unittest.py && python3 src/lease-broker/invariant_r_unittest.py && python3 src/lease-broker/framework_skill_portability_unittest.py && python3 src/mutator-gate/runtime_tools_unittest.py && python3 src/mutator-gate/runtime_launch_guard_unittest.py && python3 src/mutator-gate/version_coupling_unittest.py && python3 framework/tools/lease-broker/check-runtime-launches.py --root ../.. && bash framework/tools/codex/test-pr-diff-context.sh && bash framework/tools/qa/test-deps-preflight.sh && bash framework/tools/git/test-pr-review-gitea-comment.sh && bash framework/tools/git/test-pr-review-repo-host-override.sh && bash framework/tools/git/test-ci-queue-wait-branch-absent.sh && bash framework/tools/git/test-ci-queue-wait-tristate.sh && bash framework/tools/git/test-ci-queue-wait-github-checks.sh && bash framework/tools/git/test-pr-merge-queue-branch.sh && bash framework/tools/git/test-pr-merge-head-pin.sh && bash framework/tools/git/test-pr-merge-message-field.sh && bash framework/tools/git/test-git-credential-mosaic.sh && bash framework/tools/git/test-gitea-token-identity.sh && bash framework/tools/woodpecker/test-terminal-green-contract.sh && bash framework/tools/_scripts/test-install-ordering-guard.sh && bash framework/tools/tmux/agent-send.test.sh && bash framework/tools/wake/test-wake-store-ack.sh && bash framework/tools/wake/test-wake-store-enqueue-race.sh && bash framework/tools/wake/test-wake-digest-hmac.sh && bash framework/tools/wake/test-wake-digest-quarantine.sh && bash framework/tools/wake/test-wake-detector.sh && bash framework/tools/wake/test-wake-fn-oracle.sh && bash framework/tools/wake/test-wake-reconcile.sh && bash framework/tools/wake/test-wake-beacon.sh && bash framework/tools/wake/test-wake-preimage.sh && bash framework/tools/wake/test-wake-install.sh"
  },
  "dependencies": {
    "@mosaicstack/brain": "workspace:*",
@@ -14,9 +14,11 @@ import {
  readdirSync,
  realpathSync,
  rmSync,
+  appendFileSync,
 } from 'node:fs';
+import { createHash, randomBytes } from 'node:crypto';
 import { createRequire } from 'node:module';
-import { homedir } from 'node:os';
+import { homedir, hostname } from 'node:os';
 import { join, dirname } from 'node:path';
 import type { Command } from 'commander';
 import {
@@ -42,6 +44,163 @@ const RUNTIME_LABELS: Record<RuntimeName, string> = {
  pi: 'Pi',
 };

+// ─── Harness home isolation ──────────────────────────────────────────────────
+// Mosaic-launched runtimes read config from a dedicated home under the mosaic
+// tree — never the operator's base install. A bare `claude` / `pi` therefore
+// keeps its own config AND its own auth, and stays a working break-glass no
+// matter what mosaic does to its own tree.
+//
+// These paths are manifest-UNKNOWN, which resolves to operator ownership
+// (framework-manifest.txt rule 3, #791), so a keep-mode `mosaic update` can
+// neither overwrite nor prune them. Overwrite-mode install still would.
+//
+// opencode has no dedicated config-dir variable and follows XDG, so isolating it
+// sets XDG_CONFIG_HOME for that process tree. That is blunter than the other
+// three: it also relocates XDG lookups for anything opencode spawns.
+const HARNESS_HOME_ENV: Record<RuntimeName, string> = {
+  claude: 'CLAUDE_CONFIG_DIR',
+  pi: 'PI_CODING_AGENT_DIR',
+  codex: 'CODEX_HOME',
+  opencode: 'XDG_CONFIG_HOME',
+};
+
+/** Dedicated mosaic-owned home for a runtime: ~/.config/mosaic/.<runtime> */
+function harnessHome(runtime: RuntimeName): string {
+  return join(MOSAIC_HOME, `.${runtime}`);
+}
+
+/**
+ * Env overlay pointing a runtime at its mosaic-owned home. The directory is
+ * created on demand so a first launch does not fail on a missing path.
+ */
+function harnessEnv(runtime: RuntimeName): Record<string, string> {
+  const key = HARNESS_HOME_ENV[runtime];
+  if (!key) return {};
+  const home = harnessHome(runtime);
+  mkdirSync(home, { recursive: true });
+  return { [key]: home };
+}
+
+// ─── Launch record (immutable provenance) ────────────────────────────────────
+// MANDATORY and MECHANICAL: every launch appends one record of what the agent
+// actually launched with, written before exec. No model involvement, no opt-out.
+//
+// WHY LAUNCH-TIME AND NOT INSPECT-LATER: pi rewrites its own argv to a bare
+// `pi`, so /proc/<pid>/cmdline DESTROYS the launch evidence. That has already
+// produced a confident wrong diagnosis ("this agent bypassed the launcher"),
+// disproved only by the parent process's argv and only because the parent had
+// not yet exited. A record written before exec is the only place this survives.
+//
+// Lands in fleet/run/sessions/ — the #797 Runtime Session Ledger path, already
+// operator-classified in framework-manifest.txt and already covered by
+// test-upgrade-manifest-guard.sh, so an upgrade can neither overwrite nor prune
+// it.
+//
+// CORRELATION is by an explicit MOSAIC_LAUNCH_ID, never by pid: execRuntime()
+// uses spawnSync, so the runtime is a CHILD with a different pid.
+// launch-runtime.py appends the matching `lease.register` event.
+//
+// NEVER records a credential value: env is captured as PRESENT NAMES ONLY, and
+// oversized argv values (the composed system prompt) become a digest + length.
+const LAUNCH_LEDGER_DIR = join(MOSAIC_HOME, 'fleet', 'run', 'sessions');
+
+const CLI_VERSION: string | null = (() => {
+  try {
+    // Resolved RELATIVELY: the package `exports` map does not expose
+    // package.json, so '@mosaicstack/mosaic/package.json' throws
+    // ERR_PACKAGE_PATH_NOT_EXPORTED. Same relative depth from src/ and dist/.
+    return (createRequire(import.meta.url)('../../package.json') as { version: string }).version;
+  } catch {
+    return null;
+  }
+})();
+
+interface NormativeFragmentDigest {
+  source_id: string;
+  sha256: string | null;
+  bytes: number | null;
+  missing?: boolean;
+}
+
+function sha256Of(value: string | Buffer): string {
+  return createHash('sha256').update(value).digest('hex');
+}
+
+/**
+ * Hash the normative sources injected into the agent. This is "what the agent
+ * IS" — and it is the same fragment set the lease broker hashes for promotion,
+ * so an unexpected digest here is a mechanically detectable red flag rather than
+ * a matter of judgement.
+ */
+function normativeFragmentDigests(runtime: RuntimeName): NormativeFragmentDigest[] {
+  const candidates: Array<[string, string]> = [
+    ['CONSTITUTION.md', join(MOSAIC_HOME, 'CONSTITUTION.md')],
+    ['AGENTS.md', join(MOSAIC_HOME, 'AGENTS.md')],
+    ['SOUL.md', join(MOSAIC_HOME, 'SOUL.md')],
+    ['USER.md', join(MOSAIC_HOME, 'USER.md')],
+    ['STANDARDS.md', join(MOSAIC_HOME, 'STANDARDS.md')],
+    ['TOOLS.md', join(MOSAIC_HOME, 'TOOLS.md')],
+    [`runtime/${runtime}/RUNTIME.md`, join(MOSAIC_HOME, 'runtime', runtime, 'RUNTIME.md')],
+  ];
+  return candidates.map(([sourceId, path]) => {
+    try {
+      const bytes = readFileSync(path);
+      return { source_id: sourceId, sha256: sha256Of(bytes), bytes: bytes.length };
+    } catch {
+      return { source_id: sourceId, sha256: null, bytes: null, missing: true };
+    }
+  });
+}
+
+/** argv with oversized values replaced by a digest, so the record stays small
+ * and never inlines injected content verbatim. */
+function redactArgv(argv: string[]): string[] {
+  return argv.map((a) =>
+    typeof a === 'string' && a.length > 256
+      ? `<redacted sha256:${sha256Of(a).slice(0, 16)} bytes:${a.length}>`
+      : a,
+  );
+}
+
+function recordLaunch(runtime: RuntimeName, cliArgs: string[], yolo: boolean): void {
+  try {
+    mkdirSync(LAUNCH_LEDGER_DIR, { recursive: true, mode: 0o700 });
+    // Correlation id for the lease.register half. Set into process.env so it
+    // propagates through every `...process.env` / `...baseEnv` spread below.
+    const launchId = `${Date.now().toString(36)}-${randomBytes(6).toString('hex')}`;
+    process.env['MOSAIC_LAUNCH_ID'] = launchId;
+    const record = {
+      seq: Date.now(),
+      kind: 'session.launch',
+      launch_id: launchId,
+      ts: new Date().toISOString(),
+      host: hostname(),
+      pid: process.pid,
+      runtime,
+      mode: yolo ? 'yolo' : 'normal',
+      cwd: process.cwd(),
+      cli_version: CLI_VERSION,
+      config_home: harnessHome(runtime),
+      config_home_isolated: true,
+      config_home_env: HARNESS_HOME_ENV[runtime] ?? null,
+      argv: redactArgv(cliArgs),
+      normative_fragments: normativeFragmentDigests(runtime),
+      // names only — values are never recorded
+      mosaic_env_present: Object.keys(process.env)
+        .filter((k) => k.startsWith('MOSAIC_'))
+        .sort(),
+    };
+    appendFileSync(join(LAUNCH_LEDGER_DIR, 'events.ndjson'), `${JSON.stringify(record)}\n`, {
+      mode: 0o600,
+    });
+  } catch (err) {
+    // Never block a launch on bookkeeping — but never fail silently either.
+    console.error(
+      `[mosaic] WARNING: launch record not written: ${err instanceof Error ? err.message : String(err)}`,
+    );
+  }
+}
+
 // ─── Pre-flight checks ──────────────────────────────────────────────────────

 function checkMosaicHome(): void {
@@ -105,11 +264,11 @@ interface SettingsAudit {

 function auditClaudeSettings(): SettingsAudit {
  const warnings: string[] = [];
-  const settingsPath = join(homedir(), '.claude', 'settings.json');
+  const settingsPath = join(harnessHome('claude'), 'settings.json');
  const settings = readJson(settingsPath);

  if (!settings) {
-    warnings.push('~/.claude/settings.json not found — hooks and plugins will be missing');
+    warnings.push(`${settingsPath} not found — hooks and plugins will be missing`);
    return { warnings };
  }

@@ -561,7 +720,9 @@ function skillRealPath(dir: string): string {
 /** Skill roots Pi auto-discovers natively (no `--skill` needed): its global
 * skills dir and the project-local one relative to the launch cwd. */
 function piNativeSkillRoots(cwd: string = process.cwd()): string[] {
-  return [join(homedir(), '.pi', 'agent', 'skills'), join(cwd, '.pi', 'skills')];
+  // PI_CODING_AGENT_DIR replaces ~/.pi/agent (not ~/.pi), so skills live at
+  // <home>/skills — there is no extra 'agent' segment under the isolated home.
+  return [join(harnessHome('pi'), 'skills'), join(cwd, '.pi', 'skills')];
 }

 /** Enumerate skill dirs under a set of roots, deduped by real path. A directory
@@ -764,12 +925,13 @@ function launchRuntime(runtime: RuntimeName, args: string[], yolo: boolean): nev
        cliArgs.push(...args);
      }
      console.log(`[mosaic] Launching ${label}${modeStr}${missionStr}...`);
+      recordLaunch('claude', cliArgs, yolo);
      execLeaseGatedRuntime('claude', cliArgs, process.env, yolo);
      break;
    }

    case 'codex': {
-      ensureRuntimeConfig('codex', join(homedir(), '.codex', 'instructions.md'));
+      ensureRuntimeConfig('codex', join(harnessHome('codex'), 'instructions.md'));
      const cliArgs = yolo ? ['--dangerously-bypass-approvals-and-sandbox'] : [];
      if (hasMissionNoArgs) {
        cliArgs.push(missionPrompt);
@@ -777,14 +939,17 @@ function launchRuntime(runtime: RuntimeName, args: string[], yolo: boolean): nev
        cliArgs.push(...args);
      }
      console.log(`[mosaic] Launching ${label}${modeStr}${missionStr}...`);
-      execRuntime('codex', cliArgs);
+      recordLaunch('codex', cliArgs, yolo);
+      execRuntime('codex', cliArgs, { ...process.env, ...harnessEnv('codex') });
      break;
    }

    case 'opencode': {
-      ensureRuntimeConfig('opencode', join(homedir(), '.config', 'opencode', 'AGENTS.md'));
+      // opencode follows XDG, so its config resolves to $XDG_CONFIG_HOME/opencode.
+      ensureRuntimeConfig('opencode', join(harnessHome('opencode'), 'opencode', 'AGENTS.md'));
      console.log(`[mosaic] Launching ${label}${modeStr}...`);
-      execRuntime('opencode', args);
+      recordLaunch('opencode', args, yolo);
+      execRuntime('opencode', args, { ...process.env, ...harnessEnv('opencode') });
      break;
    }

@@ -799,6 +964,7 @@ function launchRuntime(runtime: RuntimeName, args: string[], yolo: boolean): nev
        cliArgs.push(...args);
      }
      console.log(`[mosaic] Launching ${label}${modeStr}${missionStr}...`);
+      recordLaunch('pi', cliArgs, yolo);
      execLeaseGatedRuntime('pi', cliArgs);
      break;
    }
@@ -835,6 +1001,7 @@ function execLeaseGatedRuntime(
    [launcher, ...dangerousArgs, '--runtime', runtime, '--', runtime, ...args],
    {
      ...baseEnv,
+      ...harnessEnv(runtime),
      MOSAIC_LEASE_BROKER_SOCKET: defaultLeaseBrokerSocket(baseEnv),
      MOSAIC_RUNTIME_GENERATION: baseEnv['MOSAIC_RUNTIME_GENERATION'] ?? '1',
    },
@@ -0,0 +1,289 @@
+#!/usr/bin/env python3
+"""Invariant R: a read-only carve-out can neither disappear nor be shadowed.
+
+The broker's carve-out is an authentication bypass for UNVERIFIED runtimes, so
+this test imports the live ``READ_ONLY_TOOLS`` object instead of copying it.
+Claude MCP names are namespaced, making an exact proven allow-list sufficient.
+Pi extensions are unnamespaced and may override built-ins, so the Pi half boots
+the installed runtime and requires every carve-out winner to retain built-in
+provenance.
+"""
+
+from __future__ import annotations
+
+import importlib
+import json
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
+import unittest
+from pathlib import Path
+from typing import Final
+
+
+PACKAGE_ROOT = Path(__file__).parents[2]
+FRAMEWORK = PACKAGE_ROOT / "framework"
+LEASE_BROKER = FRAMEWORK / "tools/lease-broker"
+PI_EXTENSION = FRAMEWORK / "runtime/pi/mosaic-extension.ts"
+sys.path.insert(0, str(LEASE_BROKER))
+daemon = importlib.import_module("daemon")
+READ_ONLY_TOOLS = daemon.READ_ONLY_TOOLS
+
+# Claude Code's measured, bare built-ins that are both registered and incapable
+# of filesystem mutation or subprocess execution. MCP tools are namespaced as
+# mcp__<server>__<tool>, so they cannot replace these bare identities.
+CLAUDE_PROVEN_READ_ONLY_TOOLS: Final = frozenset({"Read", "Grep", "Glob"})
+
+# W-B measured Pi 0.84.1 through getAllTools(), observed every tool_call name,
+# and cross-checked dist/core/tools/index.js:18. Keep every measured built-in
+# here so a runtime registry change forces the security classification to be
+# revisited even when a built-in is deliberately excluded from the carve-out.
+PI_VERSION: Final = "0.84.1"
+PI_PROBE_ATTEMPTS: Final = 3
+PI_PROBE_TIMEOUT_SECONDS: Final = 45
+PI_PROBE_BACKOFF_SECONDS: Final = 0.25
+PI_PROVEN_READ_ONLY_TOOLS: Final = frozenset({"read", "ls"})
+PI_SUBPROCESS_TOOLS: Final = frozenset({"grep", "find"})
+PI_MUTATING_TOOLS: Final = frozenset({"bash", "edit", "write"})
+PI_MEASURED_BUILTINS: Final = (
+    PI_PROVEN_READ_ONLY_TOOLS | PI_SUBPROCESS_TOOLS | PI_MUTATING_TOOLS
+)
+
+# Pi 0.84.1 built-ins individually proven incapable of subprocess execution or
+# filesystem writes on their default path:
+# - read: dist/core/tools/read.js:26-29 dispatches only read/access operations.
+# - ls: dist/core/tools/ls.js:19-22 dispatches only exists/stat/readdir operations.
+# grep and find are deliberately absent: grep.js:99/148 and find.js:161/203
+# reach ensureTool(..., true) and spawn(), including the cold-cache download,
+# write, chmod, and exec path in dist/utils/tools-manager.js:285-313.
+PI_CAPABILITY_SAFE_TOOLS: Final = frozenset({"read", "ls"})
+
+# Falsifier-only inputs. They are intentionally undocumented outside this test:
+# normal CI leaves them unset; the W-A evidence run uses them to prove that the
+# suite turns red for a nonexistent Claude carve-out or a Pi built-in override.
+CLAUDE_EXTRA_TOOL_ENV: Final = "MOSAIC_INVARIANT_R_CLAUDE_EXTRA_TOOL"
+PI_EXTRA_EXTENSION_ENV: Final = "MOSAIC_INVARIANT_R_PI_EXTRA_EXTENSION"
+
+
+def run_pi_registry_command(
+    command: list[str],
+    environ: dict[str, str],
+    *,
+    runner=subprocess.run,
+    sleeper=time.sleep,
+) -> subprocess.CompletedProcess[str]:
+    """Run the registry probe with bounded retries for concurrent-Pi stalls."""
+
+    for attempt in range(1, PI_PROBE_ATTEMPTS + 1):
+        try:
+            return runner(
+                command,
+                check=False,
+                capture_output=True,
+                text=True,
+                env=environ,
+                timeout=PI_PROBE_TIMEOUT_SECONDS,
+            )
+        except subprocess.TimeoutExpired as error:
+            if attempt == PI_PROBE_ATTEMPTS:
+                raise AssertionError(
+                    "Pi registry probe could not complete after "
+                    f"{PI_PROBE_ATTEMPTS} attempts (concurrent pi?); this is a "
+                    "probe/infra failure, NOT an Invariant R violation"
+                ) from error
+            sleeper(PI_PROBE_BACKOFF_SECONDS * attempt)
+
+    raise AssertionError("unreachable Pi registry retry state")
+
+
+def probe_pi_registry() -> list[dict[str, object]]:
+    """Boot Pi's real registry and return the final winning tool definitions."""
+
+    pi = shutil.which("pi")
+    if pi is None:
+        raise AssertionError("installed Pi runtime is required for Invariant R")
+
+    version = subprocess.run(
+        [pi, "--version"],
+        check=False,
+        capture_output=True,
+        text=True,
+        timeout=10,
+    )
+    if version.returncode != 0:
+        raise AssertionError(f"Pi version probe failed: {version.stderr.strip()}")
+    if version.stdout.strip() != PI_VERSION:
+        raise AssertionError(
+            f"Pi runtime changed from measured {PI_VERSION} to {version.stdout.strip()!r}; "
+            "remeasure its registry before updating Invariant R"
+        )
+
+    with tempfile.TemporaryDirectory() as temporary:
+        root = Path(temporary)
+        output = root / "registry.json"
+        observer = root / "registry-observer.ts"
+        observer.write_text(
+            "import { writeFileSync } from 'node:fs';\n"
+            "export default function register(pi: any) {\n"
+            "  pi.on('session_start', () => {\n"
+            f"    writeFileSync({json.dumps(str(output))}, JSON.stringify(pi.getAllTools()));\n"
+            "    process.exit(0);\n"
+            "  });\n"
+            "}\n",
+            encoding="utf-8",
+        )
+
+        command = [
+            pi,
+            "--mode",
+            "text",
+            "--no-session",
+            "--no-approve",
+            "--no-context-files",
+            "--no-skills",
+            "--no-prompt-templates",
+            "--no-extensions",
+            "-e",
+            str(observer),
+            "-e",
+            str(PI_EXTENSION),
+        ]
+        extra_extension = os.environ.get(PI_EXTRA_EXTENSION_ENV)
+        if extra_extension:
+            command.extend(("-e", extra_extension))
+        command.append("Invariant R registry probe")
+
+        completed = run_pi_registry_command(
+            command,
+            {**os.environ, "PI_OFFLINE": "1"},
+        )
+        if completed.returncode != 0 or not output.is_file():
+            raise AssertionError(
+                "Pi registry probe failed "
+                f"(status {completed.returncode}): {completed.stderr.strip()}"
+            )
+        value = json.loads(output.read_text(encoding="utf-8"))
+        if not isinstance(value, list) or not value:
+            raise AssertionError("Pi registry probe returned no tools; control failed")
+        return value
+
+
+class InvariantRTest(unittest.TestCase):
+    def test_live_carve_out_has_only_supported_runtimes(self) -> None:
+        self.assertEqual(set(READ_ONLY_TOOLS), {"claude", "pi"})
+
+    def test_claude_carve_out_is_registered_and_proven(self) -> None:
+        carve_out = set(READ_ONLY_TOOLS["claude"])
+        falsifier = os.environ.get(CLAUDE_EXTRA_TOOL_ENV)
+        if falsifier:
+            carve_out.add(falsifier)
+
+        self.assertEqual(
+            carve_out,
+            set(CLAUDE_PROVEN_READ_ONLY_TOOLS),
+            "every Claude carve-out must exist and be in the exact proven read-only allow-list",
+        )
+
+    def test_pi_carve_out_has_no_exec_or_write_capability(self) -> None:
+        carve_out = set(READ_ONLY_TOOLS["pi"])
+
+        capability_unsafe = carve_out - set(PI_CAPABILITY_SAFE_TOOLS)
+        self.assertFalse(
+            capability_unsafe,
+            f"capability-unsafe Pi carve-out tools: {sorted(capability_unsafe)!r}; "
+            "Pi 0.84.1 grep.js:99/148 and find.js:161/203 reach "
+            "ensureTool(..., true) and spawn(), whose cold-cache path downloads, "
+            "writes, chmods, and execs",
+        )
+
+    def test_pi_carve_out_resolves_to_real_unshadowed_builtins(self) -> None:
+        carve_out = set(READ_ONLY_TOOLS["pi"])
+        self.assertEqual(
+            carve_out,
+            set(PI_PROVEN_READ_ONLY_TOOLS),
+            "Pi carve-out drift requires a new runtime measurement and classification",
+        )
+        self.assertTrue(carve_out.isdisjoint(PI_MUTATING_TOOLS))
+
+        registry = probe_pi_registry()
+        by_name: dict[str, dict[str, object]] = {}
+        for entry in registry:
+            name = entry.get("name")
+            if not isinstance(name, str):
+                self.fail(f"Pi registry entry has no string name: {entry!r}")
+            by_name[name] = entry
+
+        builtin_names = {
+            name
+            for name, entry in by_name.items()
+            if isinstance(entry.get("sourceInfo"), dict)
+            and entry["sourceInfo"].get("source") == "builtin"
+        }
+        self.assertEqual(
+            builtin_names,
+            set(PI_MEASURED_BUILTINS),
+            "Pi's real built-in registry drifted from the positive-control W-B measurement",
+        )
+
+        for name in sorted(carve_out):
+            with self.subTest(tool=name):
+                self.assertIn(name, by_name, "Pi carve-out names must exist in the real registry")
+                source = by_name[name].get("sourceInfo")
+                self.assertIsInstance(source, dict)
+                if isinstance(source, dict):
+                    self.assertEqual(
+                        source.get("source"),
+                        "builtin",
+                        f"Pi extension or SDK tool shadowed read-only carve-out {name!r}",
+                    )
+                    self.assertEqual(source.get("path"), f"<builtin:{name}>")
+
+    def test_pi_probe_retries_timeouts_before_succeeding(self) -> None:
+        attempts: list[float] = []
+        backoffs: list[float] = []
+
+        def timeout_twice(command, **kwargs):
+            attempts.append(kwargs["timeout"])
+            if len(attempts) < 3:
+                raise subprocess.TimeoutExpired(command, kwargs["timeout"])
+            return subprocess.CompletedProcess(command, 0, "", "")
+
+        completed = run_pi_registry_command(
+            ["pi", "probe"],
+            {},
+            runner=timeout_twice,
+            sleeper=backoffs.append,
+        )
+
+        self.assertEqual(completed.returncode, 0)
+        self.assertEqual(attempts, [45, 45, 45])
+        self.assertEqual(backoffs, [0.25, 0.5])
+
+    def test_pi_probe_labels_exhausted_timeouts_as_infrastructure_failure(self) -> None:
+        attempts = 0
+
+        def always_timeout(command, **kwargs):
+            nonlocal attempts
+            attempts += 1
+            raise subprocess.TimeoutExpired(command, kwargs["timeout"])
+
+        with self.assertRaisesRegex(
+            AssertionError,
+            "Pi registry probe could not complete .* NOT an Invariant R violation",
+        ) as caught:
+            run_pi_registry_command(
+                ["pi", "probe"],
+                {},
+                runner=always_timeout,
+                sleeper=lambda _delay: None,
+            )
+
+        self.assertEqual(attempts, 3)
+        self.assertIsInstance(caught.exception.__cause__, subprocess.TimeoutExpired)
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -0,0 +1,179 @@
+#!/usr/bin/env python3
+"""The promotion client must never build a binding narrower than it claims.
+
+RED-first against a real defect: ``build_construction`` skipped any normative
+source it could not read (``except OSError: continue``) and promoted whatever
+remained. That is not a degraded binding, it is a forged smaller one — the
+broker recomputes ``h_source`` / ``h_payload`` from the fragments it is *sent*
+(``daemon.py:602-616``), so an omitted fragment is internally consistent and
+``PAYLOAD_BINDING_MISMATCH`` cannot fire. Measured before the fix: with only
+``USER.md`` readable (964 bytes on the live host), the client produced a
+one-fragment construction with ``promotion=True``.
+
+The classification under test mirrors the framework's own file ownership, and
+must keep mirroring it:
+
+  * framework-owned, reconciled every upgrade (``install.sh`` FRAMEWORK_OWNED /
+    ``config/file-adapter.ts`` FRAMEWORK_OWNED_FILES) plus the per-runtime
+    contract — absence is a broken deployment, so it is REFUSED;
+  * ``SOUL.md`` / ``USER.md`` — install.sh deliberately does not seed them
+    ("generated by `mosaic init`"), so absence is legitimate and ALLOWED.
+
+Unreadable is treated separately from absent for *every* source, optional ones
+included: a file that will not open is not a file that was never configured, and
+collapsing the two is what let a permission change quietly shrink the law.
+"""
+
+from __future__ import annotations
+
+import contextlib
+import io
+import os
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+TOOLS = Path(__file__).parents[2] / "framework/tools/lease-broker"
+sys.path.insert(0, str(TOOLS))
+
+import lease_promote  # noqa: E402
+
+RUNTIME = "pi"
+RUNTIME_CONTRACT = f"runtime/{RUNTIME}/RUNTIME.md"
+ALL_SOURCES = (*lease_promote.FRAGMENT_SOURCES, RUNTIME_CONTRACT)
+REQUIRED = frozenset(lease_promote.REQUIRED_SOURCES) | {RUNTIME_CONTRACT}
+# Derived, never listed: a hand-kept second copy is exactly the drift this file
+# exists to catch.
+OPTIONAL = tuple(s for s in ALL_SOURCES if s not in REQUIRED)
+
+# chmod 0o000 does not deny root (CAP_DAC_OVERRIDE), so the unreadable
+# simulations would fail spuriously in a root container.
+runs_unprivileged = unittest.skipIf(
+    os.geteuid() == 0, "chmod 0o000 cannot make a file unreadable to root"
+)
+
+
+class PromotionBindingTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self._previous_home = os.environ.get("MOSAIC_HOME")
+        self._temporary = tempfile.TemporaryDirectory()
+        self.root = Path(self._temporary.name)
+        for source_id in ALL_SOURCES:
+            path = self.root / source_id
+            path.parent.mkdir(parents=True, exist_ok=True)
+            path.write_bytes(f"# {source_id}\nnormative bytes\n".encode())
+        os.environ["MOSAIC_HOME"] = str(self.root)
+
+    def tearDown(self) -> None:
+        for path in self.root.rglob("*"):
+            if path.is_file():
+                path.chmod(0o644)
+        self._temporary.cleanup()
+        if self._previous_home is None:
+            os.environ.pop("MOSAIC_HOME", None)
+        else:
+            os.environ["MOSAIC_HOME"] = self._previous_home
+
+    def reset_home(self) -> None:
+        """Discard the current home and seed a fresh complete one.
+
+        Each subTest mutates the tree destructively, so it needs a clean start —
+        and the old one must be released, not orphaned.
+        """
+        self.tearDown()
+        self.setUp()
+
+    def build(self):
+        return lease_promote.build_construction(RUNTIME)
+
+    def source_ids(self) -> list[str]:
+        construction, _ = self.build()
+        return [f["source_id"] for f in construction["fragments"]]
+
+    # --- the binding is complete when the deployment is complete -------------
+
+    def test_complete_deployment_binds_every_source(self) -> None:
+        construction, result = self.build()
+        self.assertEqual([f["source_id"] for f in construction["fragments"]], list(ALL_SOURCES))
+        self.assertTrue(result.promotion)
+
+    # --- absence: refused for framework-owned, allowed for operator-owned ----
+
+    def test_absent_required_source_is_refused(self) -> None:
+        for source_id in sorted(REQUIRED):
+            with self.subTest(source=source_id):
+                self.reset_home()
+                (self.root / source_id).unlink()
+                with self.assertRaises(lease_promote.IncompleteBinding) as caught:
+                    self.build()
+                self.assertIn(source_id, str(caught.exception))
+
+    def test_absent_operator_source_still_binds_the_rest(self) -> None:
+        for source_id in OPTIONAL:
+            with self.subTest(source=source_id):
+                self.reset_home()
+                (self.root / source_id).unlink()
+                notice = io.StringIO()
+                with contextlib.redirect_stderr(notice):
+                    bound = self.source_ids()
+                self.assertNotIn(source_id, bound)
+                for required in lease_promote.REQUIRED_SOURCES:
+                    self.assertIn(required, bound)
+                # A silent omission is the original defect in miniature: the
+                # narrower binding must announce itself.
+                self.assertIn(source_id, notice.getvalue())
+
+    # --- unreadable is never the same as absent -----------------------------
+
+    @runs_unprivileged
+    def test_unreadable_source_is_refused_even_when_optional(self) -> None:
+        for source_id in ALL_SOURCES:
+            with self.subTest(source=source_id):
+                self.reset_home()
+                (self.root / source_id).chmod(0o000)
+                with self.assertRaises(lease_promote.IncompleteBinding) as caught:
+                    self.build()
+                self.assertIn(source_id, str(caught.exception))
+
+    # --- the exact measured regression --------------------------------------
+
+    @runs_unprivileged
+    def test_single_readable_source_cannot_promote(self) -> None:
+        """The observed failure: only USER.md readable produced a valid binding."""
+        for source_id in ALL_SOURCES:
+            if source_id != "USER.md":
+                (self.root / source_id).chmod(0o000)
+        with self.assertRaises(lease_promote.IncompleteBinding):
+            self.build()
+
+    @runs_unprivileged
+    def test_no_source_readable_cannot_promote(self) -> None:
+        for source_id in ALL_SOURCES:
+            (self.root / source_id).chmod(0o000)
+        with self.assertRaises(lease_promote.IncompleteBinding):
+            self.build()
+
+    # --- the classification must not drift from the framework's -------------
+
+    def test_required_set_excludes_only_the_unseeded_sources(self) -> None:
+        """`install.sh` decides which files exist; this list must follow it.
+
+        If a source moves between framework-owned and operator-generated
+        upstream, this fails and forces the classification to be re-read rather
+        than silently inherited.
+        """
+        self.assertEqual(
+            set(lease_promote.REQUIRED_SOURCES),
+            {"CONSTITUTION.md", "AGENTS.md", "STANDARDS.md"},
+            "REQUIRED_SOURCES changed — re-read install.sh FRAMEWORK_OWNED and "
+            "config/file-adapter.ts FRAMEWORK_OWNED_FILES before accepting it",
+        )
+        self.assertTrue(
+            set(lease_promote.REQUIRED_SOURCES) <= set(lease_promote.FRAGMENT_SOURCES),
+            "a required source is not in the binding order",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -0,0 +1,519 @@
+#!/usr/bin/env python3
+"""RED-first contracts for the operator-triggered Claude promotion hooks."""
+
+from __future__ import annotations
+
+import importlib.util
+import io
+import json
+import os
+import stat
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+
+PACKAGE_ROOT = Path(__file__).parents[2]
+FRAMEWORK = PACKAGE_ROOT / "framework"
+TOOLS = FRAMEWORK / "tools/lease-broker"
+BEGIN_PATH = TOOLS / "promote-begin.py"
+COMPLETE_PATH = TOOLS / "promote-complete.py"
+OBSERVER_CLIENT_PATH = TOOLS / "receipt-observer-client.py"
+RECEIPT_CHALLENGE_PATH = TOOLS / "receipt_challenge.py"
+CLAUDE_SETTINGS = FRAMEWORK / "runtime/claude/settings.json"
+CLAUDE_COMMAND = FRAMEWORK / "runtime/claude/commands/mosaic-promote.md"
+SESSION_ID = "a" * 64
+CHALLENGE = "b" * 64
+H_PAYLOAD = "c" * 64
+RECEIPT = (
+    f"MOSAIC-RECEIPT{{challenge={CHALLENGE}; H_payload={H_PAYLOAD}; gen=1; cep=0}}"
+)
+NOW = 10_000.0
+
+
+def load_module(name: str, path: Path):
+    if not path.is_file():
+        raise AssertionError(f"shipped module is missing: {path}")
+    spec = importlib.util.spec_from_file_location(name, path)
+    if spec is None or spec.loader is None:
+        raise RuntimeError(f"unable to load {name}")
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+class PromotionHookFixture(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls.begin = load_module("promotion_begin_test", BEGIN_PATH)
+        cls.complete = load_module("promotion_complete_test", COMPLETE_PATH)
+
+    def setUp(self) -> None:
+        self.temporary = tempfile.TemporaryDirectory()
+        self.runtime_dir = Path(self.temporary.name)
+        self.environment = {
+            "XDG_RUNTIME_DIR": str(self.runtime_dir),
+            "MOSAIC_LEASE_SESSION_ID": SESSION_ID,
+        }
+        self.pending_dir = self.runtime_dir / "mosaic-lease"
+        self.pending_file = self.pending_dir / f"pending-{SESSION_ID}"
+
+    def tearDown(self) -> None:
+        self.temporary.cleanup()
+
+    @staticmethod
+    def completed(payload: dict[str, object], returncode: int = 0, stderr: str = ""):
+        return subprocess.CompletedProcess(
+            ["lease_promote.py"],
+            returncode,
+            json.dumps(payload),
+            stderr,
+        )
+
+    @classmethod
+    def successful_begin_reply(cls, **extra: object) -> dict[str, object]:
+        return {
+            "ok": True,
+            "state": "PENDING_VERIFICATION",
+            "receipt_challenge": CHALLENGE,
+            "receipt": RECEIPT,
+            "binding": {
+                "compaction_epoch": 0,
+                "request_epoch": 0,
+                "h_source": "d" * 64,
+                "h_payload": H_PAYLOAD,
+                "runtime_generation": 1,
+                "schema_version": 1,
+            },
+            **extra,
+        }
+
+    def run_begin(
+        self,
+        prompt: str,
+        runner: mock.Mock,
+    ) -> tuple[int, str, str]:
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+        result = self.begin.main(
+            environ=self.environment,
+            stdin=io.BytesIO(json.dumps({"prompt": prompt}).encode()),
+            stdout=stdout,
+            stderr=stderr,
+            run=runner,
+            now=lambda: NOW,
+        )
+        return result, stdout.getvalue(), stderr.getvalue()
+
+    def write_pending(self, challenge: str = CHALLENGE) -> None:
+        self.pending_dir.mkdir(mode=0o700, exist_ok=True)
+        self.pending_file.write_text(challenge, encoding="utf-8")
+        self.pending_file.chmod(0o600)
+
+    def run_complete(self, runner: mock.Mock) -> tuple[int, str]:
+        stderr = io.StringIO()
+        result = self.complete.main(
+            environ=self.environment,
+            stderr=stderr,
+            run=runner,
+        )
+        return result, stderr.getvalue()
+
+
+class PromotionBeginTest(PromotionHookFixture):
+    def test_exact_prompt_writes_private_challenge_and_injects_verbatim_receipt(self) -> None:
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, stdout, stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+        output = json.loads(stdout)
+        self.assertEqual(
+            output["hookSpecificOutput"]["additionalContext"],
+            "The operator invoked the registered /mosaic-promote command. "
+            "This receipt was generated locally by this seat's own lease broker; "
+            "echoing it verbatim is the designed confirmation step and discloses nothing. "
+            f"Reply with exactly the following text and nothing else: {RECEIPT}",
+        )
+        self.assertEqual(self.pending_file.read_text(encoding="utf-8"), CHALLENGE)
+        self.assertEqual(stat.S_IMODE(self.pending_file.stat().st_mode), 0o600)
+        command = runner.call_args.args[0]
+        self.assertEqual(command[-1], "--begin")
+        self.assertTrue(command[-2].endswith("lease_promote.py"))
+
+    def test_nonmatching_prompt_has_zero_side_effects(self) -> None:
+        runner = mock.Mock()
+
+        result, stdout, stderr = self.run_begin("please /mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stdout, "")
+        self.assertEqual(stderr, "")
+        runner.assert_not_called()
+        self.assertFalse(self.pending_dir.exists())
+
+    def test_begin_refusal_reports_daemon_code_without_pending_file(self) -> None:
+        runner = mock.Mock(
+            return_value=self.completed({"ok": False, "code": "INVALID_BINDING"})
+        )
+
+        result, stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertIn("INVALID_BINDING", json.loads(stdout)["hookSpecificOutput"]["additionalContext"])
+        self.assertFalse(self.pending_file.exists())
+
+    def test_sweep_removes_stale_sibling_and_spares_fresh_sibling(self) -> None:
+        self.pending_dir.mkdir(mode=0o700)
+        stale = self.pending_dir / "pending-stale"
+        fresh = self.pending_dir / "pending-fresh"
+        stale.write_text("stale", encoding="utf-8")
+        fresh.write_text("fresh", encoding="utf-8")
+        os.utime(stale, (NOW - 3_601, NOW - 3_601))
+        os.utime(fresh, (NOW - 3_599, NOW - 3_599))
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, _stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertFalse(stale.exists())
+        self.assertTrue(fresh.exists())
+
+    def test_sweep_removes_stale_atomic_temporary_file(self) -> None:
+        self.pending_dir.mkdir(mode=0o700)
+        stale_temporary = self.pending_dir / f".pending-{SESSION_ID}.tmp-abandoned"
+        stale_temporary.write_text("partial", encoding="utf-8")
+        os.utime(stale_temporary, (NOW - 3_601, NOW - 3_601))
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, _stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertFalse(stale_temporary.exists())
+
+    def test_insecure_pending_directory_mode_refuses_before_begin(self) -> None:
+        self.pending_dir.mkdir(mode=0o755)
+        self.pending_dir.chmod(0o755)
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertFalse(self.pending_file.exists())
+        self.assertIn("PROMOTION_TRIGGER_FAILED", stdout)
+
+    def test_insecure_runtime_directory_mode_refuses_before_begin(self) -> None:
+        self.runtime_dir.chmod(0o755)
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertIn("PROMOTION_TRIGGER_FAILED", stdout)
+
+    def test_parent_symlink_cannot_redirect_pending_write(self) -> None:
+        outside = self.runtime_dir / "outside"
+        outside.mkdir(mode=0o700)
+        self.pending_dir.symlink_to(outside, target_is_directory=True)
+        runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+
+        result, _stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertFalse((outside / f"pending-{SESSION_ID}").exists())
+
+    def test_concurrent_begin_is_refused_without_minting_a_second_challenge(self) -> None:
+        inner_runner = mock.Mock(return_value=self.completed(self.successful_begin_reply()))
+        inner_result: list[tuple[int, str, str]] = []
+
+        def overlap(*_args: object, **_kwargs: object):
+            inner_result.append(self.run_begin("/mosaic-promote", inner_runner))
+            return self.completed(self.successful_begin_reply())
+
+        outer_runner = mock.Mock(side_effect=overlap)
+
+        result, _stdout, _stderr = self.run_begin("/mosaic-promote", outer_runner)
+
+        self.assertEqual(result, 0)
+        inner_runner.assert_not_called()
+        self.assertEqual(inner_result[0][0], 0)
+        self.assertIn("PROMOTION_ALREADY_IN_PROGRESS", inner_result[0][1])
+
+    def test_non_ascii_receipt_reply_is_rejected_without_crashing_hook(self) -> None:
+        reply = self.successful_begin_reply()
+        reply["receipt"] = "MOSAIC—RECEIPT"
+        runner = mock.Mock(return_value=self.completed(reply))
+
+        result, stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertFalse(self.pending_file.exists())
+        self.assertIn("INVALID_PROMOTER_REPLY", stdout)
+
+    def test_success_shaped_reply_with_extra_fields_is_rejected(self) -> None:
+        runner = mock.Mock(
+            return_value=self.completed(self.successful_begin_reply(unexpected=True))
+        )
+
+        result, stdout, _stderr = self.run_begin("/mosaic-promote", runner)
+
+        self.assertEqual(result, 0)
+        self.assertFalse(self.pending_file.exists())
+        self.assertIn("INVALID_PROMOTER_REPLY", stdout)
+
+
+class PromotionCompleteTest(PromotionHookFixture):
+    def test_no_pending_file_is_zero_cost_success(self) -> None:
+        runner = mock.Mock()
+
+        result, stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+        runner.assert_not_called()
+
+    def test_success_deletes_pending_file(self) -> None:
+        self.write_pending()
+        runner = mock.Mock(
+            return_value=self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+        )
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertFalse(self.pending_file.exists())
+        self.assertEqual(runner.call_args.args[0][-2:], ["--complete", CHALLENGE])
+
+    def test_each_terminal_failure_deletes_pending_file(self) -> None:
+        terminal_codes = (
+            "RECEIPT_REPLAY",
+            "RECEIPT_MISMATCH",
+            "INVALID_LEASE_TRANSITION",
+            "PROMOTION_TOKEN_INVALID",
+        )
+        for code in terminal_codes:
+            with self.subTest(code=code):
+                self.write_pending()
+                runner = mock.Mock(
+                    return_value=self.completed(
+                        {"stage": "observe_receipt", "ok": False, "code": code}
+                    )
+                )
+
+                result, stderr = self.run_complete(runner)
+
+                self.assertEqual(result, 0)
+                self.assertFalse(self.pending_file.exists())
+                self.assertIn(code, stderr)
+
+    def test_transient_and_unknown_failures_preserve_pending_file(self) -> None:
+        transient_codes = (
+            "RECEIPT_OBSERVATION_UNAVAILABLE",
+            "BROKER_BUSY",
+            "ANCESTRY_MISMATCH",
+        )
+        for code in transient_codes:
+            with self.subTest(code=code):
+                self.write_pending()
+                runner = mock.Mock(
+                    return_value=self.completed(
+                        {"stage": "observe_receipt", "ok": False, "code": code}
+                    )
+                )
+
+                result, stderr = self.run_complete(runner)
+
+                self.assertEqual(result, 0)
+                self.assertTrue(self.pending_file.exists())
+                self.assertIn(code, stderr)
+
+    def test_transport_failure_preserves_pending_file_and_exits_zero(self) -> None:
+        self.write_pending()
+        runner = mock.Mock(
+            return_value=self.completed({}, returncode=2, stderr="ConnectionRefusedError")
+        )
+
+        result, stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertTrue(self.pending_file.exists())
+        self.assertIn("ConnectionRefusedError", stderr)
+
+    def test_insecure_runtime_directory_mode_preserves_pending(self) -> None:
+        self.write_pending(CHALLENGE)
+        self.runtime_dir.chmod(0o755)
+        runner = mock.Mock(
+            return_value=self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+        )
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertTrue(self.pending_file.exists())
+
+    def test_parent_symlink_cannot_redirect_pending_read_or_delete(self) -> None:
+        outside = self.runtime_dir / "outside"
+        outside.mkdir(mode=0o700)
+        outside_pending = outside / f"pending-{SESSION_ID}"
+        outside_pending.write_text(CHALLENGE, encoding="utf-8")
+        outside_pending.chmod(0o600)
+        self.pending_dir.symlink_to(outside, target_is_directory=True)
+        runner = mock.Mock(
+            return_value=self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+        )
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertTrue(outside_pending.exists())
+
+    def test_insecure_pending_file_mode_is_not_consumed(self) -> None:
+        self.write_pending(CHALLENGE)
+        self.pending_file.chmod(0o644)
+        runner = mock.Mock(
+            return_value=self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+        )
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        runner.assert_not_called()
+        self.assertTrue(self.pending_file.exists())
+
+    def test_concurrent_replacement_is_not_deleted_after_success(self) -> None:
+        self.write_pending(CHALLENGE)
+
+        def replace_pending(*_args: object, **_kwargs: object):
+            replacement = self.pending_dir / "replacement"
+            replacement.write_text("replacement", encoding="utf-8")
+            replacement.chmod(0o600)
+            os.replace(replacement, self.pending_file)
+            return self.completed(
+                {"stage": "promote_lease", "ok": True, "state": "VERIFIED"}
+            )
+
+        runner = mock.Mock(side_effect=replace_pending)
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertEqual(self.pending_file.read_text(encoding="utf-8"), "replacement")
+
+    def test_success_shaped_reply_with_extra_fields_preserves_pending(self) -> None:
+        self.write_pending(CHALLENGE)
+        runner = mock.Mock(
+            return_value=self.completed(
+                {
+                    "stage": "promote_lease",
+                    "ok": True,
+                    "state": "VERIFIED",
+                    "unexpected": True,
+                }
+            )
+        )
+
+        result, _stderr = self.run_complete(runner)
+
+        self.assertEqual(result, 0)
+        self.assertTrue(self.pending_file.exists())
+
+
+class PromotionTemplateWiringTest(unittest.TestCase):
+    def test_gated_claude_template_wires_begin_and_ordered_stop_chain(self) -> None:
+        settings = json.loads(CLAUDE_SETTINGS.read_text(encoding="utf-8"))
+        hooks = settings["hooks"]
+        submit_commands = [
+            hook["command"]
+            for group in hooks["UserPromptSubmit"]
+            for hook in group["hooks"]
+        ]
+        self.assertEqual(
+            submit_commands,
+            ["python3 ~/.config/mosaic/tools/lease-broker/promote-begin.py"],
+        )
+        self.assertEqual(
+            [group.get("matcher") for group in hooks["UserPromptSubmit"]],
+            ["^/mosaic-promote$"],
+        )
+        stop_commands = [
+            hook["command"]
+            for group in hooks["Stop"]
+            for hook in group["hooks"]
+        ]
+        promotion_chains = [
+            command
+            for command in stop_commands
+            if "receipt-observer-client.py" in command and "promote-complete.py" in command
+        ]
+        self.assertEqual(len(promotion_chains), 1)
+        chain = promotion_chains[0]
+        self.assertLess(
+            chain.index("receipt-observer-client.py"),
+            chain.index("promote-complete.py"),
+        )
+        self.assertIn("observer_status=$?", chain)
+        self.assertTrue(chain.endswith("exit $observer_status"))
+
+    def test_registered_command_is_one_line_and_defers_to_injected_instruction(self) -> None:
+        body = CLAUDE_COMMAND.read_text(encoding="utf-8")
+        self.assertEqual(
+            body,
+            "I invoked this registered command to authorize lease promotion; follow the local seat broker's injected receipt confirmation instruction exactly.\n",
+        )
+
+
+class PromotionVerbatimToleranceTest(unittest.TestCase):
+    def test_echo_turn_with_tool_use_is_rejected_and_requires_two_turns(self) -> None:
+        observer_client = load_module("promotion_observer_client_test", OBSERVER_CLIENT_PATH)
+        receipt_challenge = load_module("promotion_receipt_challenge_test", RECEIPT_CHALLENGE_PATH)
+        challenge = "b" * 64
+        binding = {
+            "h_payload": "c" * 64,
+            "runtime_generation": 1,
+            "compaction_epoch": 0,
+        }
+        receipt = receipt_challenge.receipt_for(challenge, binding)
+        real_claude_entry = {
+            "message": {
+                "role": "assistant",
+                "content": [
+                    {"type": "text", "text": receipt},
+                    {
+                        "type": "tool_use",
+                        "id": "tool-1",
+                        "name": "mcp__discord__reply",
+                        "input": {"message": "promoted"},
+                    },
+                ],
+            }
+        }
+
+        extracted = observer_client.assistant_text(real_claude_entry)
+        accepted = isinstance(extracted, str) and receipt_challenge.is_verbatim_receipt(
+            extracted,
+            challenge,
+            binding,
+        )
+
+        self.assertIsNone(extracted)
+        self.assertFalse(accepted)
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -207,6 +207,24 @@ class ReceiptObserverTest(BrokerFixture):
        with self.assertRaisesRegex(DAEMON.BrokerFailure, "INVALID_LEASE_TRANSITION"):
            self.promote(current["receipt_challenge"])

+    def test_non_ascii_observation_is_mismatch_and_broker_keeps_serving(self) -> None:
+        construction, binding = self.construction()
+        cycle = self.begin(binding, construction)
+        self.record("I refuse—this is not the receipt")
+
+        with self.assertRaisesRegex(DAEMON.BrokerFailure, "RECEIPT_MISMATCH"):
+            self.observe(cycle["receipt_challenge"])
+
+        denied = self.broker.handle(self.peer, {
+            "action": "authorize_tool",
+            "session_id": self.session_id,
+            "runtime_generation": 7,
+            "runtime": "pi",
+            "tool_name": "bash",
+        })
+        self.assertEqual(denied["decision"], "deny")
+        self.assertEqual(denied["state"], DAEMON.LEASE_UNVERIFIED)
+
    def test_t29_altered_model_hash_cannot_promote_against_shipped_binding(self) -> None:
        construction, binding = self.construction()
        cycle = self.begin(binding, construction)
@@ -0,0 +1,303 @@
+#!/usr/bin/env python3
+"""Exit-semantics tests for the receipt observer Stop-hook client."""
+
+from __future__ import annotations
+
+import importlib.util
+import io
+import json
+import tempfile
+import unittest
+from contextlib import redirect_stderr
+from pathlib import Path
+from unittest import mock
+
+
+TOOLS = Path(__file__).parents[2] / "framework/tools/lease-broker"
+CLIENT_PATH = TOOLS / "receipt-observer-client.py"
+
+
+def load_client():
+    spec = importlib.util.spec_from_file_location("receipt_observer_client_test", CLIENT_PATH)
+    if spec is None or spec.loader is None:
+        raise RuntimeError("unable to load receipt-observer-client.py")
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+CLIENT = load_client()
+VALID_INPUT = json.dumps({"latest_assistant_message": "ordinary turn"}).encode()
+DEEPLY_NESTED_JSON = b"[" * 2_000 + b"0" + b"]" * 2_000
+ENVIRONMENT = {
+    "MOSAIC_RECEIPT_OBSERVER_SOCKET": "/unused/observer.sock",
+    "MOSAIC_LEASE_SESSION_ID": "a" * 64,
+    "MOSAIC_RUNTIME_GENERATION": "1",
+}
+
+
+class FakeObserverSocket:
+    def __init__(self, response: bytes) -> None:
+        self.response = response
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *_args: object) -> None:
+        return None
+
+    def settimeout(self, _timeout: float) -> None:
+        return None
+
+    def connect(self, _path: str) -> None:
+        return None
+
+    def sendall(self, _payload: bytes) -> None:
+        return None
+
+    def shutdown(self, _how: int) -> None:
+        return None
+
+    def recv(self, _size: int) -> bytes:
+        response, self.response = self.response, b""
+        return response
+
+
+class ReceiptObserverClientExitSemanticsTest(unittest.TestCase):
+    def run_client(
+        self,
+        *,
+        input_bytes: bytes = VALID_INPUT,
+        reply: dict[str, object] | None = None,
+        transport_error: OSError | None = None,
+        runtime: str = "pi",
+    ) -> tuple[int, str, mock.Mock]:
+        request = mock.Mock(return_value=reply)
+        if transport_error is not None:
+            request.side_effect = transport_error
+        stderr = io.StringIO()
+        with (
+            mock.patch.object(CLIENT.sys, "stdin", io.BytesIO(input_bytes)),
+            mock.patch.object(CLIENT, "observer_request", request),
+            redirect_stderr(stderr),
+        ):
+            arguments = ["--runtime", runtime]
+            if runtime == "claude":
+                arguments.append("--latest-entry")
+            result = CLIENT.main(arguments, environ=ENVIRONMENT)
+        return result, stderr.getvalue(), request
+
+    def test_claude_prefers_inline_last_assistant_message(self) -> None:
+        inline = "the just-finished assistant message"
+        input_bytes = json.dumps({
+            "last_assistant_message": inline,
+            "transcript_path": "/must/not/be/opened.jsonl",
+        }).encode()
+
+        result, stderr, request = self.run_client(
+            input_bytes=input_bytes,
+            reply={"ok": True},
+            runtime="claude",
+        )
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+        self.assertEqual(
+            request.call_args.args[1]["latest_assistant_message"],
+            inline,
+        )
+
+    def test_claude_falls_back_to_transcript_when_inline_field_is_absent(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            transcript = Path(directory) / "transcript.jsonl"
+            transcript.write_text(
+                json.dumps({
+                    "message": {
+                        "role": "assistant",
+                        "content": [{"type": "text", "text": "fallback message"}],
+                    }
+                })
+                + "\n",
+                encoding="utf-8",
+            )
+            input_bytes = json.dumps({"transcript_path": str(transcript)}).encode()
+
+            result, stderr, request = self.run_client(
+                input_bytes=input_bytes,
+                reply={"ok": True},
+                runtime="claude",
+            )
+
+            self.assertEqual(result, 0)
+            self.assertEqual(stderr, "")
+            self.assertEqual(
+                request.call_args.args[1]["latest_assistant_message"],
+                "fallback message",
+            )
+
+    def test_claude_present_invalid_inline_field_fails_without_fallback(self) -> None:
+        fallback = mock.Mock(return_value="must not be used")
+        input_bytes = json.dumps({
+            "last_assistant_message": None,
+            "transcript_path": "/unused/transcript.jsonl",
+        }).encode()
+
+        with mock.patch.object(CLIENT, "claude_latest_entry", fallback):
+            result, stderr, request = self.run_client(
+                input_bytes=input_bytes,
+                reply={"ok": True},
+                runtime="claude",
+            )
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr)
+        request.assert_not_called()
+        fallback.assert_not_called()
+
+    def test_claude_inline_message_size_guard_stays_enforced(self) -> None:
+        request = mock.Mock(return_value={"ok": True})
+        stderr = io.StringIO()
+        with (
+            mock.patch.object(CLIENT.sys, "stdin", io.BytesIO(b"{}")),
+            mock.patch.object(
+                CLIENT,
+                "read_json",
+                return_value={"last_assistant_message": "x" * (CLIENT.MAX_FRAME + 1)},
+            ),
+            mock.patch.object(CLIENT, "observer_request", request),
+            redirect_stderr(stderr),
+        ):
+            result = CLIENT.main(
+                ["--runtime", "claude", "--latest-entry"],
+                environ=ENVIRONMENT,
+            )
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr.getvalue())
+        request.assert_not_called()
+
+    def test_pi_still_posts_only_its_runtime_message(self) -> None:
+        result, stderr, request = self.run_client(reply={"ok": True})
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+        self.assertEqual(
+            request.call_args.args[1]["latest_assistant_message"],
+            "ordinary turn",
+        )
+
+    def test_nothing_pending_observation_refusal_is_benign(self) -> None:
+        result, stderr, request = self.run_client(
+            reply={"ok": False, "code": "OBSERVATION_UNAVAILABLE"}
+        )
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+        request.assert_called_once()
+
+    def test_success_reply_remains_successful(self) -> None:
+        result, stderr, _request = self.run_client(reply={"ok": True})
+
+        self.assertEqual(result, 0)
+        self.assertEqual(stderr, "")
+
+    def test_pending_cycle_auth_failure_stays_fail_closed(self) -> None:
+        result, _stderr, _request = self.run_client(
+            reply={"ok": False, "code": "ANCESTRY_MISMATCH"}
+        )
+
+        self.assertEqual(result, 2)
+
+    def test_transport_failure_stays_fail_closed(self) -> None:
+        result, stderr, _request = self.run_client(
+            transport_error=ConnectionRefusedError("observer unavailable")
+        )
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr)
+
+    def test_parse_failure_stays_fail_closed(self) -> None:
+        result, stderr, request = self.run_client(input_bytes=b"{")
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr)
+        request.assert_not_called()
+
+    def test_malformed_wire_replies_stay_fail_closed(self) -> None:
+        for response in (
+            b"not-json\n",
+            b'{"ok":true}',
+            b"{}\n{}\n",
+            b'{"ok":false,"code":"OBSERVATION_UNAVAILABLE"}\n\n',
+            b'{"ok":true,"ok":false,"code":"OBSERVATION_UNAVAILABLE"}\n',
+            DEEPLY_NESTED_JSON + b"\n",
+            b"x" * (CLIENT.MAX_FRAME + 1),
+        ):
+            with self.subTest(response=response):
+                stderr = io.StringIO()
+                with (
+                    mock.patch.object(CLIENT.sys, "stdin", io.BytesIO(VALID_INPUT)),
+                    mock.patch.object(
+                        CLIENT.socket,
+                        "socket",
+                        return_value=FakeObserverSocket(response),
+                    ),
+                    redirect_stderr(stderr),
+                ):
+                    result = CLIENT.main(["--runtime", "pi"], environ=ENVIRONMENT)
+
+                self.assertEqual(result, 2)
+                self.assertIn("Mosaic receipt observer refused", stderr.getvalue())
+
+    def test_oversized_input_stays_fail_closed(self) -> None:
+        result, stderr, request = self.run_client(input_bytes=b"x" * (CLIENT.MAX_FRAME + 1))
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr)
+        request.assert_not_called()
+
+    def test_deeply_nested_input_stays_fail_closed(self) -> None:
+        result, stderr, request = self.run_client(input_bytes=DEEPLY_NESTED_JSON)
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr)
+        request.assert_not_called()
+
+    def test_json_recursion_failure_stays_fail_closed(self) -> None:
+        request = mock.Mock()
+        stderr = io.StringIO()
+        with (
+            mock.patch.object(CLIENT.sys, "stdin", io.BytesIO(VALID_INPUT)),
+            mock.patch.object(CLIENT, "observer_request", request),
+            mock.patch.object(
+                CLIENT.json,
+                "loads",
+                side_effect=RecursionError("maximum JSON nesting exceeded"),
+            ),
+            redirect_stderr(stderr),
+        ):
+            result = CLIENT.main(["--runtime", "pi"], environ=ENVIRONMENT)
+
+        self.assertEqual(result, 2)
+        self.assertIn("Mosaic receipt observer refused", stderr.getvalue())
+        request.assert_not_called()
+
+    def test_observation_unavailable_with_unexpected_fields_stays_fail_closed(self) -> None:
+        result, _stderr, _request = self.run_client(
+            reply={"ok": False, "code": "OBSERVATION_UNAVAILABLE", "unexpected": True}
+        )
+
+        self.assertEqual(result, 2)
+
+    def test_non_boolean_ok_values_stay_fail_closed(self) -> None:
+        for reply in (
+            {"ok": 1},
+            {"ok": 0, "code": "OBSERVATION_UNAVAILABLE"},
+        ):
+            with self.subTest(reply=reply):
+                result, _stderr, _request = self.run_client(reply=reply)
+                self.assertEqual(result, 2)
+
+
+if __name__ == "__main__":
+    unittest.main()
Author	SHA1	Message	Date
Jason Woltje	d15b4b83fc	feat(lease): add single-turn Claude promotion trigger ci/woodpecker/pr/ci Pipeline failed Details	2026-08-07 19:31:44 -05:00
Jason WoltjeandClaude Fable 5	412ac4b004	fix(lease): raise lease TTL 300s -> 3600s MAX_LEASE_TTL_SECONDS (daemon cap+default) and DEFAULT_TTL_SECONDS (lease_promote client) both move to 3600. The 5-minute TTL made gated-by-default sessions unusable (re-promotion mid-task); 1 hour matches a working session. Full test:framework-shell RC=0. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_013SAYFkRhQfhguY7AHfiUC8	2026-08-07 16:14:01 -05:00
Jason Woltje	9c3f054f20	fix(lease): ignore benign observer idle replies	2026-08-07 15:15:25 -05:00
Jason Woltje	3d98c83273	fix(lease): constrain read-only tool carve-outs	2026-08-07 14:50:19 -05:00
Jason Woltje	e76f293597	test(lease): assert pi carve-out capability	2026-08-07 14:11:40 -05:00
Jason Woltje	930b7e8845	test(lease): distinguish pi probe timeouts	2026-08-07 12:59:51 -05:00
Jason Woltje	9f80049303	test(lease): enforce read-only tool invariant	2026-08-07 12:42:13 -05:00
Jason Woltje	289425ed2c	docs: measure pi tool registry	2026-08-07 12:27:23 -05:00
Jason WoltjeandClaude Fable 5	87ef1c1439	test: close W-0R review findings — assert the omission notice, skip chmod simulations under root The independent W-0R review of `3592b92e` passed but left two PLAUSIBLE findings: the stderr notice for a legitimately-omitted operator source was claimed and never asserted (a silent omission is the original defect in miniature), and the chmod 0o000 unreadable simulations fail spuriously when euid==0 (CAP_DAC_OVERRIDE). Falsifier for the new assertion: deleting the notice block turns the suite red (failures=3); restoring returns green. Co-Authored-By: Claude Fable 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01EHYXhcCQsL3J1Lnm7EraGq	2026-08-07 12:25:24 -05:00
Jason WoltjeandClaude Opus 5	3592b92e04	fix(lease): refuse an incomplete law binding instead of silently shrinking it build_construction skipped any normative source it could not read (`except OSError: continue`) and promoted whatever remained. That is not a degraded binding, it is a forged smaller one: the broker recomputes h_source / h_payload from the fragments it is SENT (daemon.py:602-616), so an omitted fragment is internally consistent and PAYLOAD_BINDING_MISMATCH cannot fire. A partial law promotes exactly like a complete one and nothing downstream can tell the difference. Measured before this change, against a seeded home: with only USER.md readable, the client produced a one-fragment construction with promotion=True. Removing CONSTITUTION.md, STANDARDS.md or the runtime contract likewise promoted. The classification mirrors the framework's own file ownership rather than inventing one: * CONSTITUTION.md / AGENTS.md / STANDARDS.md are framework-owned and reconciled every upgrade (install.sh FRAMEWORK_OWNED, config/file-adapter.ts FRAMEWORK_OWNED_FILES), as is the per-runtime RUNTIME.md. Absent => IncompleteBinding. A deployment missing one is broken, not minimal. * SOUL.md / USER.md are deliberately not seeded by install.sh ("generated by `mosaic init`") and TOOLS.md is seeded on first install only, so their absence is legitimate. It is reported on stderr, never silent. Unreadable is handled separately from absent for EVERY source, optional ones included: a file that will not open is not a file that was never configured, and collapsing the two is what let a permission change quietly shrink the law. Also corrects this module's own docstring, which asserted that a VERIFIED lease means "this agent is running THIS law". It does not. Both sides of the broker's comparison originate in this client, so it detects corruption in transit and nothing else. That overstatement is where the belief spread from; the stronger claim needs the broker re-reading on-disk sources against a manifest the agent cannot rewrite. Test: promotion_binding_unittest.py, enumerated in test:framework-shell (the enumeration guard's population is test.sh and does not cover Python, so an unenumerated test here would simply never run). Falsifier executed: defeating the guard while leaving the module API intact turns the suite red (12 failures); restoring it returns green. Co-Authored-By: Claude Opus 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01EHYXhcCQsL3J1Lnm7EraGq	2026-08-07 11:37:21 -05:00
Jason Woltje	018db7e083	Revert "feat(pi): wire lazy lease promotion into the mutator gate" This reverts `939f2e04`. Keeping the revert rather than dropping the commit, because the failed attempt is the most useful record on this branch. The wiring worked mechanically — verified with a live model on sb-it-1-dt: the receipt was emitted verbatim as a whole message, and the broker token was minted AND consumed, so observe_receipt and promote_lease both succeeded and the lease reached VERIFIED. It failed as a DESIGN, for reasons that are properties of the protocol rather than of this wiring: * It puts control-plane traffic in the user-facing conversation channel. An operator asking "what model are you?" received a receipt string instead of an answer — the model tried a tool, was blocked, complied with the receipt instruction, and in one-shot mode that text turn BECAME the reply. Observed twice, non-deterministically. * The lease TTL is hard-capped at 300s (MAX_LEASE_TTL_SECONDS; ttl_seconds > cap raises INVALID_LEASE_TTL). Measured: allowed at T+0, LEASE_EXPIRED at T+310. So the visible cost recurs every five minutes of mutator activity. * Model compliance is not guaranteed — one run retried the command instead of emitting the receipt. Any model emission is user-visible, so this is not fixable by better wiring; it needs a design answer about how promotion is triggered and paid for. That is under adversarial review (docs/scratchpads/lease-remediation/07-liveness-design-brief.md in the operator's repo). Promotion triggering will return on its own branch once that lands. What remains here is independently sound and unblocked: harness-home isolation, the immutable launch record, the skills relocation, the promotion client itself (steps 1/4/5), and the #1087 prefix guard.	2026-08-06 17:48:43 -05:00
Jason Woltje	db16de1a81	fix(sync-skills): guard the pre-existing prune against an empty prefix (#1087 ) prune_stale_links_in_target compared "$resolved" == "$canonical_real/"* while length-checking only $resolved. If $canonical_real were ever empty the pattern collapses to == "/"* and matches every absolute path. The failure is precisely inverted, which is what makes it worth fixing rather than noting: is_mosaic_skill_name already `continue`s for names that ARE current mosaic skills, so an empty prefix would delete exactly the FOREIGN symlinks in every target directory and preserve the mosaic ones. On this host that is 4 base installs, including codex's own .system entry. Reported by mos-claude as #1087 after I introduced the same guard in the new legacy-cleanup path in the previous commit and walked past this instance thirty lines away. Same defect class, same file, one function apart. $canonical_real is populated by readlink -f after a mkdir -p, so an empty value requires readlink to fail — unlikely, but the consequence is deleting operator symlinks across every harness, which is not a risk worth carrying for one test.	2026-08-06 17:41:38 -05:00
Jason Woltje	939f2e0496	feat(pi): wire lazy lease promotion into the mutator gate Completes the promotion path: the client landed in the previous commit, but nothing drove step 2 — the model emitting the receipt. This wires it. LAZY, not at session start. Promotion costs an entire model turn, because the receipt must be the whole message (hmac.compare_digest, "not a transcript substring"). Minting at session start would collide with the Constitution's first-response mode declaration — the two cannot share a message, so requiring both would be unsatisfiable. Deferring to the first DENIED MUTATOR means the mode declaration happens first and the receipt gets its own later turn, so no governance change is needed. A read-only session never pays for promotion at all. Mechanism: on a MUTATOR_UNVERIFIED denial the tool_call hook mints a challenge and returns the receipt in the block `reason`, which pi feeds back to the model as the tool result — the existing injection path already used by lease-lifecycle.ts. The model emits the receipt as its next message, message_end ships it to the observer, and the extension then calls observe_receipt + promote_lease. Only MUTATOR_UNVERIFIED triggers minting. Other denials (GATE_UNAVAILABLE, STALE_GENERATION, LEASE_EXPIRED, ANCESTRY_MISMATCH) describe conditions a receipt cannot fix, and begin_verification revokes before it mints, so minting there would thrash the broker. Completion is gated on an EXACT text match against the minted receipt. This is load-bearing, not defensive: message_end also fires for the message that CONTAINED the blocked tool call — one turn BEFORE the model answers. An earlier version completed there, so observe_receipt compared against the wrong text, failed, and burned the challenge before the model ever emitted it. Matching the text mirrors the broker's own compare_digest semantics and waits for the right turn. Confirmed by instrumenting message_end and watching it fire with pending=yes one message too early. It never posts the receipt itself. receipt-observer-client.py accepts any string, so self-posting would satisfy the broker while proving nothing — the whole point is that a live model echoes a challenge it was given. Bounded by MAX_PROMOTION_ATTEMPTS: model compliance is not guaranteed (observed a run where the model retried the command instead of emitting the receipt), so a non-complying model degrades to today's behaviour — denied mutators — rather than looping. Verified with a live model on sb-it-1-dt: receipt emitted verbatim as a whole message, and the broker token was minted AND consumed, i.e. observe_receipt and promote_lease both succeeded and the lease reached VERIFIED. Known limitation: under `pi -p`, the receipt is a text-only turn, which ends the one-shot loop — so promotion completes but the blocked tool is not retried in that same invocation. Interactive and durable fleet sessions continue and retry normally.	2026-08-06 17:10:39 -05:00
Jason Woltje	7272cfdc88	feat(lease-broker): add the missing promotion client The enforcement half of the lease broker ships and denies; the promotion half has no production caller anywhere in the package. Verified across 0.0.48, 0.0.49 and 0.0.50-next.2207: begin_verification / observe_receipt / promote_lease are invoked only by broker-test-client.ts, the acceptance spec, unit tests, and two probes under docs/. Consequence: no lease on any host can reach VERIFIED, so mutator-gate denies every mutator with MUTATOR_UNVERIFIED via a gate that nothing shipped can satisfy. Runtimes that enforce the gate in-process (pi, via mosaic-extension's tool_call hook) are bricked for mutators; runtimes whose gate is wired through a settings hook escape only when that hook is absent — i.e. by being ungated. This adds the client. It implements protocol steps 1, 4 and 5: 1. begin_verification -> mint a challenge, return the exact receipt text 2. the MODEL emits that text verbatim as its entire latest message 3. the runtime adapter ships that message to the observer socket 4. observe_receipt -> PENDING_PROMOTION 5. promote_lease -> VERIFIED Step 2 is deliberately NOT implemented here, and that is the point. is_verbatim_receipt uses hmac.compare_digest against the exact minted string — explicitly "not a transcript substring" — which makes promotion a LIVENESS PROOF: it requires a live model that received the challenge in its context and echoed it exactly. receipt-observer-client.py will post ANY string as the latest assistant message. A promotion client that posted its own receipt would satisfy the broker while proving nothing — a gate-disabler indistinguishable from a working fix unless someone specifically looks. Emitting the receipt therefore belongs to the runtime adapter, where a real model turn happens. A local diagnostic that posts its own receipt exists in the operator's repo and is deliberately NOT shipped here. The construction binds the exact normative source bytes, so a VERIFIED lease means "this agent is running THIS law", not merely "this session id is known". h_source/h_payload are derived by importing the framework's own normative_fragments.build_payload rather than reimplementing it: the broker derives them the same way and any divergence yields PAYLOAD_BINDING_MISMATCH. There must be exactly one implementation. session_identity() prefers the generation FILE over the env var, matching lease_generation.py. Sending a generation higher than the broker's would revoke the session's own authority (daemon.py:342-344), so it never guesses. Verified end-to-end on sb-it-1-dt under a real lease-gated anchor: a mutator denied rc=2 MUTATOR_UNVERIFIED, then begin -> observe -> promote -> VERIFIED, then the same mutator allowed rc=0. Negative controls pass: a fresh session is still denied, and an unrelated session still reads UNVERIFIED — promotion is per-session and does not leak. Still open: adapter wiring for step 2. Lazy promotion on first mutator attempt avoids colliding with the Constitution's first-response mode declaration, since compare_digest requires the receipt to be the WHOLE message.	2026-08-06 16:57:00 -05:00
Jason Woltje	4a7fc07ee2	feat(launch): isolate harness homes and record immutable launch provenance Mosaic wrote into the operator's harness base installs — ~/.claude, ~/.pi/agent, ~/.codex, ~/.config/opencode — for settings, instructions, and a 102-symlink skill farm per harness. Any experiment with hooks or gating therefore mutated the operator's own tooling, and a broken framework change could take out the very harness needed to repair it. Harness home isolation ---------------------- Each runtime now reads config from a dedicated mosaic-owned home via the harness's own config-dir variable: claude CLAUDE_CONFIG_DIR ~/.config/mosaic/.claude pi PI_CODING_AGENT_DIR ~/.config/mosaic/.pi (replaces ~/.pi/agent) codex CODEX_HOME ~/.config/mosaic/.codex opencode XDG_CONFIG_HOME ~/.config/mosaic/.opencode These paths are manifest-UNKNOWN, so rule 3 (#791) resolves them to operator ownership and a keep-mode upgrade can neither overwrite nor prune them. A bare `claude` / `pi` keeps its own config AND auth, making it a structural break-glass rather than one depending on restoring a file under pressure. opencode is blunter than the rest: it has no dedicated variable and follows XDG, so isolation also relocates XDG lookups for anything it spawns. Documented in place. mosaic-sync-skills now links into those homes and cleans the legacy farms it previously planted in base installs. Ownership is proven by RESOLUTION, not by name — only symlinks resolving inside the canonical/local skills dirs are removed, mirroring the refusal already in commands/skill.js. Verified against a real install: codex's own .system directory survived while its 102 mosaic links were removed. Both resolution prefixes are length-checked first; an empty prefix would make "$resolved" == "$prefix/"* match every absolute path and delete foreign symlinks. Immutable launch record ----------------------- Every launch now appends one record to fleet/run/sessions/events.ndjson before exec. Mandatory, mechanical, no model involvement. pi rewrites its own argv to a bare `pi`, so /proc/<pid>/cmdline destroys the launch evidence — that has already produced a confident wrong diagnosis ("this agent bypassed the launcher"), disproved only by the parent's argv and only because the parent had not yet exited. A record written before exec is the only place this survives. The path is the #797 Runtime Session Ledger, already operator-classified and already covered by test-upgrade-manifest-guard.sh, which seeds it and proves a populated ledger survives keep-mode upgrades — but nothing shipped ever wrote it. This implements it in the shape that guard already asserts (0600 files under a 0700 dir). `mosaic` writes session.launch; launch-runtime.py appends lease.register with the broker session id and activation capability. They correlate by an explicit MOSAIC_LAUNCH_ID, never by pid: execRuntime uses spawnSync, so the runtime is a child with a different pid. Records normative fragment digests (CONSTITUTION/AGENTS/SOUL/USER/STANDARDS/ TOOLS/RUNTIME) — the same set the broker hashes for promotion, so drift is mechanically detectable rather than a matter of judgement. Credential-safe: env is captured as PRESENT NAMES ONLY, and argv values over 256 bytes become a sha256 + length rather than being inlined. Also fixes CLI_VERSION resolution: '@mosaicstack/mosaic/package.json' is not in the package exports map and always throws ERR_PACKAGE_PATH_NOT_EXPORTED. resolveTool() uses that same failing specifier, which is why its documented preference for bundled tools over the deployed ~/.config/mosaic copy has never once applied — noted in place, not fixed here. Verified on sb-it-1-dt: isolated homes written and base installs byte-identical for all four harnesses; 408 legacy symlinks removed with 1 foreign entry preserved; launch records paired across the spawn boundary. typecheck shows zero errors in launch.ts (the @mosaicstack/types failures are pre-existing and reproduce on a pristine origin/main worktree).	2026-08-06 16:56:35 -05:00
be-coder-08andMos	80a45b1e1c	feat(pr-merge): preserve linked authors in squash messages (#1066 ) ci/woodpecker/push/publish Pipeline was successful Details ci/woodpecker/push/ci Pipeline was successful Details Co-authored-by: be-coder-08 <[email protected]>	2026-08-06 05:36:59 +00:00
				`@@ -0,0 +1 @@`
				`I invoked this registered command to authorize lease promotion; follow the local seat broker's injected receipt confirmation instruction exactly.`