> ⚠ SUPERSEDED by v8 (homelab 3rd-principal FAIL @f609a449: broker env-inherit + unpinned .pyc; PASS overtaken by stricter B7+B8 bar). This v7 PASS record is NOT fire-authorization.

# Gate0 Probe-3 (D4) Full-Closure Materialization — §3-Conformance Review v7

**Verdict: ✅ PASS** *(superseded — see banner above)*

## Pin (GUARD 1 — reviewed object)

- **Reviewed object = `f609a44953f5ae61916805fcb45ca337de00b0b0`** (harness commit, branch `feat/827-gate0-probe`).
- **Reviewed file:** `docs/compaction-refresh/probes/p3_d4_focused_run.py` — sha256 (pushed provider bytes, `-o FILE`, FULL-40 ref, verified before trust): `0f1bd1b39399b32f243d901230e2d840794a2144edd723a095dab716833a7a9b` (32071 bytes, no not-found sentinel).
- **Closure pins (independently recomputed from the git objects):**
  - launcher `packages/mosaic/framework/tools/lease-broker/launch-runtime.py` @ `f4008307` = `e950e4224e280f16979d90cabb89aa1896c5ee28bed2df957e14d018d43cda82` ✓
  - **helper** `packages/mosaic/framework/tools/lease-broker/lease_generation.py` @ `f4008307` = `061625402f08488eac47acd23272904e71fd1a71fd15b3bdab158632c801be4c` ✓
  - **broker** `docs/compaction-refresh/probes/p3_generation_broker.py` @ `23c0caca` = `4db4fef1ac6658a8ca79ad5091cefc901d2aa26003265c3d6726c294cf895cad` ✓

## Independence (GUARD 2 — principal-independence attestation)

This review is produced by a **distinct Opus SECREV session, orchestrator-dispatched — the `ms-secrev-828`
reviewer lane, dispatched by `mosaic-100`** — **byte review only, ran nothing**, that **did NOT build** this harness
(builder = ms-rev-826) and **is not Mos**. Three distinct principals: this reviewer, the builder, and Mos (whose
own distinct-identity byte-scope-verify follows); homelab's independent verify is a further principal — it is
homelab's third-principal FAIL @`2d54a9dd` (upheld by Mos) that correctly retired the approach-(i) adjacency
re-hash and authorized this full-closure. v6/`2d54a9dd`/`23c0caca`/`12914d8` are superseded.

## Why v7 (the reopen-after-hash hole)

Approach (i) re-hashed the launcher then let `Popen` **reopen the worktree path** — hashed-snapshot ≠ executed-bytes
(the worktree file is a shared, same-UID-mutable path). Statement adjacency alone did not bind. v7 closes it for the
**full project-code closure** (launcher + `lease_generation.py` helper + `p3_generation_broker.py`).

## B5 — HASHED == EXECUTED on the full closure (binding conjunction, stated verbatim)

The reopen-after-hash shape is unavoidable for imported/exec'd files, so closure rests on the **conjunction of all
three legs**, each byte-verified here:

> **(a)** bytes are materialized **from the pinned git-object @ `f4008307`** (helper/launcher) and **@ `23c0caca`**
> (broker) — `git show <commit>:<path>`, the trusted immutable object, **never the mutable worktree file**; **AND**
> **(b)** into a **fixture-private `0o700` dir with `0o600` files created via `O_CREAT|O_EXCL`** — no writer exists in
> the threat model between hash and exec; **AND** **(c)** each member is **re-hashed == its pin IMMEDIATELY before
> exec/import, fail-closed (`RuntimeError`)**.

Byte evidence:
- **(a)** `git_object_bytes(git_root, commit, relative)` = `git show <commit>:<path>` (:322-327); `materialize_closure`
  reads all three members from git objects and asserts `sha256(data) == digest` else `RuntimeError` (:415-433). Worktree
  working-tree files are never read.
- **(b)** `pinned = root / "pinned"; pinned.mkdir(mode=0o700)` (:435-436); `write_pinned_file` uses
  `os.open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0o600)` (:379-382). **No `os.chmod`/`os.rename`/`shutil.move`
  anywhere** (grep=0); `O_EXCL` refuses a pre-planted file/symlink, so no symlink-follow or hijack gap; the dir is a
  fresh per-run `mkdtemp` child, owner-only. **No code re-opens the pinned files for write between materialize and
  consume** — there is no writable window.
- **(c)** launcher re-hash `sha256(launcher.read_bytes()) == GATED_LAUNCHER_SHA256` is the statement immediately before
  `return PiRpc(command,…)` (:528-530); broker **and** helper re-hashes (`== GATED_BROKER_SHA256`,
  `== GATED_GENERATION_SHA256`) are the two statements immediately before `return subprocess.Popen(command,…)`
  (:546-551). No interleaved harness yield.

Adjacency-only exec-from-worktree is **absent** for every member (all three exec/import from `pinned/`; grep worktree-exec=0).

## B6 — helper + broker pinned and bound to execution (one shared helper)

`materialize_closure` writes exactly **one** `pinned/lease_generation.py` (:442). The broker executes the **pinned**
broker with `--generation-module = closure.generation` = that pinned helper (`launch_verified_broker`, :533-551, called
:746-747). The launcher executes the **pinned** launcher (`python3 pinned/launch-runtime.py`), whose
`import lease_generation` resolves via `sys.path[0]` = the script's own `pinned/` dir to the **same** sibling
`pinned/lease_generation.py`. Launcher-import and broker-`--generation-module` therefore resolve the **same single
pinned helper copy**, not two copies and not the worktree. Worktree helper/broker are not re-read at runtime.

**Closure-import guard:** `closure_import_guard` AST-parses each member and refuses any non-stdlib import outside the
allow-set `{"lease_generation"}` (and any relative import) → `RuntimeError` (:341-364). The 3-member closure is
therefore provably complete — no unpinned project-code dependency can slip in.

## BAR1 — Traceability

`GATED_WI_HEAD == f4008307`; the precondition asserts `git merge-base --is-ancestor 66b1e0a0 f4008307` (:315-330),
independently confirmed **YES** — the pinned launcher forward-contains the `66b1e0a0` file-backed generation mechanism.

## BAR2 — Fidelity file-backed, `.state` in fixture root, UNTOUCHED

`pinned/` holds **code bytes only** (launcher/helper/broker). The `.state` generation file is written by the launcher
to `socket_path.parent` (the fixture root), **not** `pinned/`. The broker (pinned, byte-identical `4db4fef1`) still
enforces `generation_environment` raising if `state_path.parent != socket_path.parent` (grep=2), and `assert_d4`
still checks `state_file_source == "state-file"` / `state_file_drives_lifecycle` / `state_file_in_fixture_root` +
`new→MUTATOR_UNVERIFIED` / `prior→STALE_GENERATION` (grep=4, unchanged). The v7 change did not move `.state` into
`pinned/` or perturb these asserts.

## BAR3 — Carry-over

(a) **live-path:** Pi launched via `python3 pinned/launch-runtime.py --runtime pi -- pi …` (gated register-before-exec);
`mosaic yolo`/`execRuntime` = 0. (b) **fail-closed precondition:** `gated_launcher_precondition` (resolve+materialize+
verify) runs before any launch, fail-closed. (c) **fixture-socket isolation:** `MOSAIC_LEASE_BROKER_SOCKET` = per-run
fixture socket; single pinned p3 broker serves `register_anchor`; no live/default broker reachable; non-destructive.
(d) **`lease_anchor_registered` INTACT:** event + `session_id_shape=="hex-256"` unchanged (broker byte-identical);
`assert_d4` folds it into the single-identity set — not deleted/softened/optional/repointed.

## Re-confirm + ABSENT sweep

Spawns ONLY the single pinned p3 broker; promotion=fixture-only; full D4 asserts; `--runs choices=(3,)`; allow-list
env (0 `os.environ.copy`); **`-O`-safe** (all new checks `RuntimeError`, **0 bare `assert`**); creds-scrub intact;
non-destructive (fixture tempdir only); deterministic (git objects + fixed pins); closure-import guard present.
**ABSENT = 0:** P5/P6/P2-bank/retry-launder/mosaic-yolo/execRuntime/pi_gate0; `source-invalid` grep=0; no live/real-broker
path; no `.state`/gen path outside the fixture root; no extra broker/socket; no exec-at-import (`__main__`-guarded); no
adjacency-only exec-from-worktree for any member; the only mechanism change is materialization; no scope-widen.

## Verdict

**PASS @ `f609a449`.** B5 (full-closure hashed==executed via the (a)+(b)+(c) conjunction with no writable window),
B6 (one shared pinned helper bound to both launcher-import and broker-`--generation-module`; complete closure), BAR1,
BAR2 (fidelity `.state`-in-fixture-root untouched), and BAR3 all hold, with zero out-of-scope surface. **Findings: none.**

## Scope reminder (not a finding)

Producing this evidence **executes** the Gate0 mechanism (§3/§5). This review clears **bytes** only; **FIRE remains
separately gated on Mos's explicit post-clear GO**, his v-final byte-scope-verify co-attestation, and homelab's
third-principal verify — not authorized by this review.

---

**Reviewer:** distinct Opus SECREV session (`ms-secrev-828` lane, dispatched by `mosaic-100`), Gate-16 author≠reviewer,
byte review only; ran nothing; did not build.
**Reviewed object (pin):** `f609a44953f5ae61916805fcb45ca337de00b0b0` · harness sha256 `0f1bd1b39399b32f243d901230e2d840794a2144edd723a095dab716833a7a9b`.
**Pinned closure:** launcher `e950e422…` @f4008307 · helper `06162540…be4c` @f4008307 · broker `4db4fef1…` @23c0caca.
