feat(fleet): enhancer role + two-agent floor (orchestrator + enhancer) (#614)

From Jason's north-star (docs/fleet/north-star.md, #613): every fleet has a
two-agent floor — orchestrator + enhancer minimum. Builds on #612's init-R5.

- Presets (general/coding/research/hybrid): add enhancer (claude, class:
  enhancer, persistent_persona) as a core always-on agent. minimal/local-canary
  unchanged.
- fleet.ts: countEnhancers helper; init guarantee extended — non-minimal
  profiles must yield exactly 1 orchestrator AND >=1 enhancer (hard-fail);
  removeAgentFromRoster refuses to drop the sole enhancer (symmetric with the
  sole-orchestrator guard) so the floor holds at runtime, not just init.
- framework/fleet/roles/enhancer.md: the enhancer mandate (monitor -> analyze ->
  plan -> upgrade tools/skills/harness WITH orchestrator -> file Mosaic Stack
  bug reports) + boundaries (does NOT code or review).

Verified: 155 fleet tests green (countEnhancers; sole-enhancer remove guard;
remove-allows-when-another; init two-agent-floor; every-non-minimal-preset-has-
enhancer; updated preset rosters). tsc/eslint/prettier/sanitize clean. TDD on
the init guarantee + remove protection.

Stacked on #612 (feat/fleet-polish-bundle); rebases clean onto main after #612.

Refs #614, #613

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EsgTQzV5YUGk1JtCLP4B83

.woodpecker/ci.yml

@@ -25,12 +25,10 @@ steps:
     commands:
       - apk add --no-cache bash
       - bash packages/mosaic/framework/tools/quality/scripts/verify-sanitized.sh
-      # L0 resident-token budget: keep the Constitution + dispatcher small.
+      # Resident line-count ceiling over framework-owned resident files
-      - |
+      # (Constitution + dispatcher + each RUNTIME.md slice). See DESIGN §7 / R9.
-        for f in CONSTITUTION.md AGENTS.md; do
+      - bash packages/mosaic/framework/tools/quality/scripts/check-resident-budget.sh --self-test
-          n=$(wc -l < "packages/mosaic/framework/defaults/$f")
+      - bash packages/mosaic/framework/tools/quality/scripts/check-resident-budget.sh
-          if [ "$n" -gt 120 ]; then echo "L0 budget exceeded: defaults/$f is $n lines (max 120)"; exit 1; fi
-        done
 
   typecheck:
     image: *node_image

docs/TASKS.md

@@ -45,3 +45,24 @@ Active workstream is **W1 — Federation v1**. Workers should:
 - Status: PR open, awaiting maintainer merge ratification (fleet-governing change).
 - Cut always-injected contract AGENTS+TOOLS+RUNTIME 8,827→4,122 tok (−53%); all 12 hard gates intact.
 - Validation: deterministic gate-checklist PASS; headless A/B thin 7/9 vs monolith 5/9. Detail: scratchpads/contract-thin-core.md.
+
+## P5 — Overlay composer + cross-harness (#604) — feat/p5-overlay-composer
+
+- Status: MERGED to main (#605). R7 (compose-contract) + R8 (cross-harness) + R9 (composer test).
+- `composeContract({harness, mosaicHome})` pure fn + `.local` overlay deltas-by-value; `mosaic compose-contract <harness>` command; AGENTS bare-launch nudge; composer spec (per-tier anchor + Tier-3 byte-equality). Detail: scratchpads/p5-overlay-composer.md.
+
+## P6 — Docs, compliance matrix, alpha tag (#606) — feat/p6-docs-compliance-alpha
+
+- Status: in-repo deliverables done (CONTRIBUTING.md + harness×gate compliance matrix + check-resident-budget.sh + CI wiring + ALPHA-DOD.md). Remaining: alpha tag v0.0.39-alpha (Lead, post-merge). aiguide reconcile merged (#8). Detail: scratchpads/p6-docs-compliance-alpha.md.
+
+## F3-m3 — mosaic update re-seeds framework + relaunches agents (#609) — feat/f3-m3-update-reseed
+
+- Status: implemented + tested. Closes R13: `mosaic update` now re-seeds the framework (data-safe MOSAIC_SYNC_ONLY) after the CLI install so shipped launcher/runtime changes activate; `--relaunch` restarts rostered agents; `--no-reseed` opts out. Detail: scratchpads/f3-m3-update-reseed.md.
+
+## Fleet-polish bundle — boot-survival symmetry (#611) — feat/fleet-polish-bundle
+
+- Status: implemented + tested. disable-on-remove (boot-resurrection bug, TDD) + add-enable + init-R5 hard guarantee. 4 new + 147 existing fleet tests green. Detail: scratchpads/fleet-polish-bundle.md.
+
+## Fleet enhancer role + two-agent floor (#614) — feat/fleet-enhancer-floor (stacked on #612)
+
+- Status: implemented + tested. enhancer added to 4 presets; init guarantees 1 orchestrator + >=1 enhancer; remove protects the sole enhancer; enhancer role doc. 155 fleet tests green. Detail: scratchpads/fleet-enhancer-floor.md.

docs/design/framework-constitution/ALPHA-DOD.md

@@ -0,0 +1,75 @@
+# Constitution Alpha — Definition-of-Done checklist + release notes
+
+Drafted for the `v0.0.39-alpha` tag (Lead cuts after P5 #605 → P6 #607 → aiguide #8 merge).
+Maps every DoD §8 acceptance criterion to its merged evidence. Legend:
+**✅ merged on main** · **⏳ review-ready PR (pending merge)** · **🔲 Lead action**.
+
+## DoD §8 green-checklist
+
+| #   | Acceptance criterion (DESIGN §8)                                                                       | Status | Evidence / PR     |
+| --- | ------------------------------------------------------------------------------------------------------ | ------ | ----------------- |
+| 1   | MIT `LICENSE` (root + framework) + `"license":"MIT"` in package.json                                   | ✅     | P0 #570           |
+| 2   | Three credential-path sites + hook URL fast-failed (no private paths in `*.sh`/hooks)                  | ✅     | P0 #570           |
+| 3   | `verify-sanitized.sh` (two-class, `*.sh`+`*.md`, self-tested) wired **blocking** in CI                 | ✅     | P1 #572           |
+| 4   | Operator data purged from the full set (guides / tools / init-generator)                               | ✅     | P2 #572           |
+| 5   | `rails/`→`tools/` in **both** template families                                                        | ✅     | P2 #572           |
+| 6   | `jarvis-loop.json` deleted; `defaults/SOUL.md` → **neutral sanitized persona** (Q10 decision)          | ✅     | P2 #572           |
+| 7   | `CONSTITUTION.md` extracted (gates one place, capability-verb, §1.4 split, no false "already loaded")  | ✅     | P3 #575 / #577    |
+| 8   | `AGENTS.md`/`STANDARDS.md` out of `PRESERVE_PATHS` + seed-semantics → overwrite in **both** installers | ✅     | P4 #590           |
+| 9   | Snapshot + v2→v3 migration moving user edits to `.local`/`.bak`; `FRAMEWORK_VERSION=3`                 | ✅     | P4 #590 / #593    |
+| 10  | `mosaic-init --non-interactive` fail-closed persona                                                    | ✅     | P4 #590           |
+| 11  | **5-fixture migration matrix** green against **both** installers asserting **injected bytes**          | ✅     | P4 #590 / #593    |
+| 12  | `compose-contract` built + composer unit test (per-tier anchor + Tier-3 byte-equality)                 | ⏳     | P5 #605           |
+| 13  | Resident line-count ceiling enforced (framework-owned resident files)                                  | ⏳     | P6 #607           |
+| 14  | `CONTRIBUTING.md` + harness×gate compliance matrix                                                     | ⏳     | P6 #607           |
+| 15  | `aiguide` reconciled with the Constitution                                                             | ⏳     | aiguide #8        |
+| 16  | Each phase PR CI-green; alpha tag pushed + Gitea release published                                     | 🔲     | Lead (post-merge) |
+
+**Note on #6:** the DoD's literal "delete `defaults/SOUL.md`" was superseded by the resolved
+**Q10** decision — ship a _neutral, operator-agnostic_ example persona instead of deleting it. Main
+carries the sanitized 2.6 KB neutral SOUL.md ("Mosaic agent", no operator identity); the sanitization
+gate confirms it is PII-clean. Criterion met in spirit (no operator persona leaks) via the better option.
+
+**Gate to flip 12–14 → ✅:** merge P5 #605 → P6 #607 (rebase auto-drops the dup format fix
+`adc7df2`/`9f6da92`) → aiguide #8, with `ci.yml` terminal-green on the merged head.
+
+---
+
+## Release notes — `v0.0.39-alpha` (Mosaic Framework Constitution, alpha)
+
+### Mosaic Framework Constitution — Alpha
+
+This release makes the Mosaic framework a **safe-to-open-source, fork-and-customize agent
+operating layer**. It separates the non-negotiable law from operator identity, makes
+customization survive upgrades, and wires the guarantees into CI.
+
+**Highlights**
+
+- **Constitution (L0).** The hard gates now live in one place — `CONSTITUTION.md` — authored in
+  capability verbs, with a thin `AGENTS.md` dispatcher that references the law instead of restating
+  it. Governance model in `constitution/LAYER-MODEL.md`.
+- **Public & sanitized.** MIT-licensed; all operator identity, private paths, and credential sites
+  removed from shipped files. A self-tested `verify-sanitized.sh` gate (two rule classes) runs
+  **blocking** in CI so re-contamination can't merge.
+- **Upgrade-safe customization.** Framework-owned files overwrite cleanly on upgrade while
+  `SOUL.md`/`USER.md`/`*.local.md`/`credentials` are preserved. The v2→v3 migration snapshots first
+  and moves any user-edited `AGENTS.md`/`STANDARDS.md` to `.pre-constitution.bak`/`.local.md` —
+  never silently lost. Verified by a 5-fixture matrix across **both** installers.
+- **Operator overlays.** `mosaic compose-contract <harness>` merges your `*.local.md` deltas into
+  the contract per harness, so customization reaches the model as one pre-merged blob.
+- **Cross-harness.** Single L0 source referenced (never restated) by Claude / Codex / OpenCode / Pi;
+  tiered injection with a byte-equal Tier-3 fallback read.
+- **Guardrails in CI.** Resident line-count ceiling over framework-owned resident files; composer
+  unit test; sanitization gate — all blocking.
+- **Docs.** `CONTRIBUTING.md` with the layer model, dual-installer parity rule, and a harness×gate
+  **compliance matrix** (the Codex/OpenCode/Pi hook-parity gap is tracked for v2).
+
+**Known limitations (accepted, documented in `CONTRIBUTING.md` §9)**
+
+- Bare launches that bypass `mosaic` get base contracts only (no `*.local` overlays) and are not
+  drift-checked by `mosaic doctor` — mitigated by the unconditional Tier-3 self-load + a nudge.
+- Codex/OpenCode/Pi mechanical hook parity, `policy/*.md` composition, and live-launch cross-harness
+  verification are **v2**.
+
+**Phase lineage:** P0 #570 · P1+P2 #572 · P3 #575/#577 · P4 #590/#593 · P5 #605 · P6 #607 ·
+aiguide #8 (umbrella #542).

docs/fleet/PRD-fleet-suite.md

@@ -0,0 +1,109 @@
+# PRD — Mosaic Fleet Suite (init, configure, operate)
+
+> **Workstream:** W-FLEET (Fleet) under mission `mvp-20260312` · **Phase:** 3→4 productization
+> **North star:** [docs/fleet/north-star.md](./north-star.md) · prior: Phase-2 observability (#579), durable launch (#581), real-agent enablement (#583/#584/#586), releases 0.0.35–0.0.37
+> **Lead:** Jarvis @ `w-jarvis`. **Collaborator:** coder agent @ `dragon-lin` (jwoltje@10.1.10.37:coder0-0).
+> Owner of this file: Fleet workstream lead. Does not modify MVP single-writer control-plane files.
+
+## Mission
+
+Turn the proven fleet primitives into a **user-installable, AI-free-configurable fleet product**:
+a user runs `mosaic fleet init`, answers a few questions (general / coding / research / hybrid),
+gets a recommended set of agents plus one always-on orchestrator wired for chat-ops, and can
+operate, mutate, re-create, and observe the fleet — over tmux today and Matrix tomorrow — from
+CLI/TUI and (designed-for) the webUI.
+
+**Immediate tangible goal:** the **"Mos"** orchestrator agent running on `w-jarvis`, reachable
+in **Discord channel `1517622518662434996`** (server `1112631390438166618`). Once the fleet is
+functional, we use the fleet itself to continue the work.
+
+## Requirements
+
+### A. Configure-without-AI CLI
+
+| ID  | Requirement                                                                                                   |
+| --- | ------------------------------------------------------------------------------------------------------------- |
+| R1  | `mosaic fleet` command set is functional end-to-end (init/install/start/stop/status/ps/verify + agent verbs). |
+| R2  | `mosaic fleet init` is an interactive, **AI-free** CLI wizard.                                                |
+| R3  | Init asks the **configuration type**: `general`, `coding`, `research`, `hybrid`, … (extensible).              |
+| R4  | Based on the answer, the fleet is populated with a **recommended set of agents** (a preset).                  |
+| R5  | **Exactly one main orchestrator agent** is always configured, regardless of type.                             |
+| R10 | A set of **recommended configurations (presets)** ships for easy duplication.                                 |
+| R8  | User can **re-create** the fleet when config needs change (idempotent re-init / reconfigure).                 |
+| R17 | Fleet controls are **simple and intuitive**.                                                                  |
+
+### B. Comms & orchestrator chat-ops
+
+| ID  | Requirement                                                                                                                       |
+| --- | --------------------------------------------------------------------------------------------------------------------------------- |
+| R6  | Init can wire the orchestrator to a chat connector — **Telegram / Discord / Matrix / Slack** — for command + comms.               |
+| R7  | Designed with the end-goal of **Matrix comms on a locally-controlled server**.                                                    |
+| R16 | Fleet supports **tmux AND Matrix** comms, **user-configurable** at init or any time. Not all users want Matrix.                   |
+| R19 | **"Mos" orchestrator on Discord** (`chan 1517622518662434996` / `srv 1112631390438166618`) on `w-jarvis` — the first live target. |
+
+### C. Runtime, health, lifecycle
+
+| ID  | Requirement                                                                        |
+| --- | ---------------------------------------------------------------------------------- |
+| R9  | Fleet is **mutable by the orchestrator agent** — add/remove agents per need.       |
+| R13 | Fleet **gracefully handles Pi + Claude harness updates** — keep harnesses current. |
+| R14 | The **Pi harness is customized** for proper tool usage, etc.                       |
+| R15 | **Agent heartbeat** properly configured for **Claude AND GPT/Pi** agents.          |
+
+### D. Surfaces, testing, docs
+
+| ID  | Requirement                                                                         |
+| --- | ----------------------------------------------------------------------------------- |
+| R18 | Fleet built so the **webUI can view / monitor / terminate / butt-in** on a session. |
+| R11 | Installed and **tested on both `w-jarvis` and `dragon-lin`**.                       |
+| R12 | **Documentation**: how to install, configure, and use the fleet.                    |
+
+## Architecture / approach
+
+- **Config model:** `roster.yaml` is the source of truth (already exists). Add **presets** (`general`/`coding`/`research`/`hybrid`) as shipped example rosters; `init` selects a preset, always injects the orchestrator, and writes the roster. Re-init = regenerate roster (preserve user/site overrides — mirrors install env-merge from #567).
+- **Orchestrator agent:** always present; carries the chat connector config (connector type + target IDs) so it can be commanded over chat. tmux is the substrate; the connector bridges chat ↔ the orchestrator session.
+- **Comms layers (R16):** (1) **tmux** inter-agent (`agent-send`, proven) — default, always available. (2) **chat connector** for human↔orchestrator (Discord now; Matrix the strategic target). (3) **Matrix** as the locally-controlled cross-agent bus (future). Connector is pluggable + reconfigurable.
+- **Heartbeat (R15):** runtime-agnostic launcher sidecar already covers pi/claude/codex (#584). Refine per-runtime (native HB) with the **custom Pi harness** (R14) + a Claude path.
+- **Updates (R13):** `mosaic update` (CLI) + a fleet-aware harness-update step that refreshes pi/claude/codex and re-launches agents safely (drain → update → relaunch via the durable launcher).
+- **webUI (R18):** the fleet exposes machine-readable state (`fleet ps --json` already carries tenant/host/heartbeat/managed) + control verbs (start/stop/watch/send); webUI consumes these (control plane rides federation per north star). Ensure a stable JSON contract + a terminate/attach(butt-in) path.
+
+## Phases (incremental, each shippable)
+
+| Phase                             | Deliverable                                                                                                                         | Notes                                 |
+| --------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------- |
+| **F1 Presets + init wizard**      | preset rosters (general/coding/research/hybrid) + always-orchestrator + AI-free `fleet init` selecting a preset; re-init idempotent | R1–R5, R8, R10, R17                   |
+| **F2 Connector + Mos-on-Discord** | orchestrator chat-connector config (Discord first) + **Mos live on Discord `1517…`/`1112…`** on w-jarvis                            | R6, R19, partial R16                  |
+| **F3 Heartbeat + harness**        | HB confirmed for claude + pi/gpt; **custom Pi harness** (tool usage, native HB, model self-report); graceful harness updates        | R13, R14, R15                         |
+| **F4 Matrix + comms toggle**      | Matrix connector (local server) + user toggle tmux/Matrix at init/anytime                                                           | R7, R16                               |
+| **F5 Orchestrator-mutable fleet** | orchestrator can add/remove agents at runtime                                                                                       | R9                                    |
+| **F6 webUI hooks**                | stable JSON contract + terminate/attach surface for webUI view/monitor/terminate/butt-in                                            | R18                                   |
+| **F7 Test + docs**                | install+test on w-jarvis AND dragon-lin; user docs (install/configure/use)                                                          | R11, R12 (runs alongside every phase) |
+
+## Work division (proposed — confirm with dragon-lin)
+
+- **Jarvis @ w-jarvis (Lead):** F1 presets+wizard, F2 connector+Mos-on-Discord, F5 mutability, F6 webUI hooks; merge authority + dual-engine reviews; co-testing on w-jarvis.
+- **coder @ dragon-lin:** F3 custom Pi harness + harness-update flow (pi/codex-savvy); plus its in-flight constitution P4–P6 (P4 installer rework underpins `fleet init`/updates — coordinate the install path). Co-testing on dragon-lin (R11).
+- **Shared:** F4 Matrix (whoever has bandwidth); F7 testing/docs continuous.
+
+## Immediate target: Mos on Discord (F2 first slice)
+
+The discord plugin is available (`~/.claude.json`). Path: configure the **orchestrator** as a durable
+fleet session running Claude Code with the discord plugin bridged to channel `1517622518662434996`
+(server `1112631390438166618`) on w-jarvis, with the existing Discord Bridge Protocol (ack within
+~3s, reply via `mcp__discord__reply`, no `AskUserQuestion`). Heartbeat via the launcher sidecar.
+
+## Success criteria
+
+- A non-AI user can `mosaic fleet init`, pick a type, and get a working fleet + orchestrator.
+- **Mos answers in Discord `1517…`** on w-jarvis.
+- Fleet runs + is observable (`fleet ps`) on **both** w-jarvis and dragon-lin.
+- Harness updates handled gracefully; HB healthy for claude + pi/gpt agents.
+- Docs let a new operator install/configure/use the fleet.
+- Re-init + orchestrator mutation work.
+
+## Assumptions (veto-able)
+
+- `ASSUMPTION:` presets ship as example rosters under the framework (`fleet/examples/*.yaml`), selected by `init`.
+- `ASSUMPTION:` chat connectors are pluggable; Discord first (target exists), Matrix is the strategic default later.
+- `ASSUMPTION:` "Mos" = a Claude Code orchestrator session with the discord plugin (reuses the documented Discord Bridge Protocol).
+- `ASSUMPTION:` per north star, runtimes default to Codex/pi-on-Codex for workers; the orchestrator "Mos" runs Claude Code (in Claude Code, which is allowed).

docs/scratchpads/f3-m3-update-reseed.md

@@ -0,0 +1,29 @@
+# F3-m3 — `mosaic update` re-seeds framework + relaunches agents (R13)
+
+- **Issue:** #609 · **Branch:** `feat/f3-m3-update-reseed`
+
+## Gap (found in 0.0.39 production validation)
+
+`mosaic update` installs the new npm CLI but never re-seeds `~/.config/mosaic/` from the package's
+bundled `framework/`. So the shipped custom Pi harness (agent-name export + native HB, 0.0.39) stays
+DORMANT until a re-seed — operators get the new CLI on a stale framework.
+
+## Implementation
+
+- `update-checker.ts`: `resolveBundledFrameworkRoot()`, `buildReseedCommand()` (install.sh in
+  `MOSAIC_SYNC_ONLY=1 MOSAIC_INSTALL_MODE=keep` — the P4 data-safe reconcile), `runFrameworkReseed()`,
+  `readRosterAgentNames()`, `buildRelaunchCommands()` (systemctl --user restart per agent).
+- `cli.ts` `update`: after a successful CLI install that includes `@mosaicstack/mosaic`, re-seed the
+  framework (default-on; `--no-reseed` to skip). Then either `--relaunch` (restart rostered agents) or
+  print clear guidance to run `mosaic update --relaunch` / `mosaic fleet restart`.
+
+## Flow
+
+`update CLI → re-seed framework (data-safe) → relaunch agents (opt-in)` — closes R13, activates the
+native harness for every operator.
+
+## Verification
+
+- 6 new unit tests (reseed command/env, relaunch commands, roster parse, missing-installer guard).
+- 19 runtime + 26 launch tests still green; tsc/eslint/prettier clean.
+- Data-safety of the sync is already proven (P4 5-fixture matrix + live dragon-lin validation).

docs/scratchpads/fleet-enhancer-floor.md

@@ -0,0 +1,26 @@
+# Fleet enhancer role + two-agent floor (#614)
+
+- **Issue:** #614 · **Branch:** `feat/fleet-enhancer-floor` (stacked on #612 `feat/fleet-polish-bundle`)
+- **Doctrine:** `docs/fleet/north-star.md` (PR #613) — every fleet = orchestrator + enhancer minimum.
+
+## Changes
+
+- **Presets** (general, coding, research, hybrid): add `enhancer` (claude, `class: enhancer`,
+  `persistent_persona: true`) as a core always-on agent alongside the orchestrator. minimal/local-canary
+  unchanged.
+- **fleet.ts**: `countEnhancers` helper; init guarantee extended — non-minimal profiles must yield
+  exactly 1 orchestrator AND >=1 enhancer (hard-fail otherwise); `removeAgentFromRoster` refuses to drop
+  the sole enhancer (symmetric with the sole-orchestrator guard) so the floor holds at runtime, not just init.
+- **Role doc**: `framework/fleet/roles/enhancer.md` — the enhancer mandate (monitor → analyze → plan →
+  upgrade tools/skills/harness WITH orchestrator → file Mosaic Stack bug reports) + boundaries (does NOT
+  code or review).
+
+## Verification
+
+- 155 fleet tests green (new: countEnhancers; remove-sole-enhancer guard; remove-allows-when-another;
+  init two-agent-floor; every-non-minimal-preset-has-enhancer; updated preset rosters). tsc/eslint/
+  prettier/sanitize clean. TDD on the init guarantee + remove protection.
+
+## Stacking
+
+Built on #612's init-R5 code. PR shows #612 + enhancer until #612 merges; then rebase onto main → clean.

docs/scratchpads/fleet-polish-bundle.md

@@ -0,0 +1,20 @@
+# Fleet-polish bundle — boot-survival symmetry (#611)
+
+- **Issue:** #611 · **Branch:** `feat/fleet-polish-bundle` · From the Lead's Codex symmetry-gap finding.
+
+## Three fixes
+
+1. **disable-on-remove (BUG, TDD).** `fleet remove` stopped + deleted roster/env/heartbeat but never
+   `systemctl --user disable mosaic-agent@NAME.service` → a removed-but-enabled unit could resurrect on
+   reboot pointing at deleted config. Fix: `buildSystemdDisableCommand` + disable in `remove`
+   (best-effort, gated on !--keep-files).
+2. **add-enable.** `fleet add` now enables the new agent's unit for boot-survival (best-effort,
+   independent of --start) — symmetry with disable-on-remove.
+3. **init-R5 guarantee.** `fleet init --write` now FAILS HARD when a non-minimal profile doesn't yield
+   exactly one orchestrator (was a soft warning). `minimal` (sanctioned no-orchestrator) still allowed.
+
+## Verification
+
+- 4 new tests (disable builder; remove-invokes-disable; add-invokes-enable; init general → exactly 1
+  orchestrator) + 147 existing fleet tests green (151 total). tsc/eslint/prettier clean.
+- TDD on the disable bug per contract.

docs/scratchpads/p5-overlay-composer.md

@@ -0,0 +1,43 @@
+# P5 — Overlay composer + cross-harness (compose-contract)
+
+- **Issue:** #604 · **Branch:** `feat/p5-overlay-composer` · **Lineage:** #542 → constitution alpha
+- **Requirements:** R7 (compose-contract) + R8 (cross-harness) + R9 (composer test)
+- **Design of record:** `docs/design/framework-constitution/{DESIGN.md §3.2, PRD.md §4}` (on `feat/framework-constitution-alpha`)
+
+## Locked design (sequential-thinking)
+
+Current `launch.ts` assembly (`buildComposedPrompt`) injects by value: mission + PRD + hard-gate +
+CONSTITUTION + AGENTS + USER + TOOLS + runtime. It does **not** inject SOUL or STANDARDS (those are
+read-on-demand per the gutted AGENTS dispatcher), and has no `.local` overlay support.
+
+**Decision (ASSUMPTION — recorded for the PR):** overlays are injected as **deltas by value** under
+labeled sections; base files keep their existing residency.
+
+- `USER.local.md` → appended directly under the `# User Profile` block (USER is injected).
+- `SOUL.local.md` + `STANDARDS.local.md` → a trailing `# Operator Overlays` section (their bases are
+  load-on-demand, so only the small delta is injected — not the full base prose).
+- **Why:** honors DESIGN §3.2 ("model gets one pre-merged blob, no read-merge ritual") while preserving
+  the P3 byte-budget tiering (don't re-inject large SOUL/STANDARDS prose). Precedence order kept: base
+  layers first, operator overlays at recency.
+- Base-only is automatic when a `.local` file is absent (`readOptional`).
+
+## Plan
+
+| #   | Task                                                                                                   | File                                    |
+| --- | ------------------------------------------------------------------------------------------------------ | --------------------------------------- |
+| 1   | Extract `composeContract({harness, mosaicHome})` pure fn; `buildComposedPrompt` delegates              | `src/commands/launch.ts`                |
+| 2   | Overlay logic (USER.local under profile; SOUL/STANDARDS.local in `# Operator Overlays`)                | `src/commands/launch.ts`                |
+| 3   | `mosaic compose-contract <harness>` command → prints blob to stdout                                    | `src/commands/launch.ts`                |
+| 4   | Bare-launch overlay nudge in self-load fallback                                                        | `framework/defaults/AGENTS.md`          |
+| 5   | `compose-contract.spec.ts`: per-tier anchor, Tier-3 byte-equality, overlay present/absent, per-harness | `src/commands/compose-contract.spec.ts` |
+
+## Deferred to P6
+
+CONTRIBUTING.md + harness×gate compliance matrix; resident line-count CI ceiling; `aiguide` reconcile;
+alpha tag `mosaic-vX.Y.Z-alpha`.
+
+## Status
+
+- [x] Phase scaffold (branch, issue #604, scratchpad, TASKS)
+- [ ] Implementation (tasks 1–5)
+- [ ] prettier + vitest green; PR via wrapper → Lead (rides 0.0.39; 0.0.38 mid-cut)

docs/scratchpads/p6-docs-compliance-alpha.md

@@ -0,0 +1,29 @@
+# P6 — Docs, compliance matrix, alpha tag (constitution capstone)
+
+- **Issue:** #606 · **Branch:** `feat/p6-docs-compliance-alpha` · **Lineage:** #542
+- **Requirements:** R9 (resident line-count ceiling) + R10 (CONTRIBUTING + compliance matrix + aiguide) + alpha tag
+
+## Delivered (in-repo)
+
+- `framework/CONTRIBUTING.md` — layer model, operator-hygiene/PII prohibition, dedup rule, resident
+  budget, **dual-installer parity rule**, adding-a-harness, re-contamination rule, **harness×gate
+  compliance matrix** (hook-parity gap marked ⚠️ tracked-v2), known-limitations (§9 residuals), PR checklist.
+- `framework/tools/quality/scripts/check-resident-budget.sh` — line-count ceiling over framework-owned
+  resident files (CONSTITUTION + AGENTS + each runtime/\*/RUNTIME.md); `--self-test`; replaces the crude
+  inline ci.yml loop. Wired blocking in `.woodpecker/ci.yml`.
+- Composer unit test (R9) already runs via `pnpm test`; `verify-sanitized.sh` (P1) already wired.
+
+## Verification
+
+- Sanitization gate green (CONTRIBUTING is operator-neutral). Resident-budget self-test + real run green.
+- prettier clean. Current resident counts: CONSTITUTION 96, AGENTS 83, RUNTIME max 75 — all < ceiling.
+
+## Remaining
+
+- [ ] `aiguide` reconcile (separate repo `~/src/aiguide` / mosaicstack/aiguide) — consistency pass vs Constitution.
+- [ ] Alpha tag `mosaic-vX.Y.Z-alpha` — propose version; Lead cuts after full DoD §8 green + all phases merged.
+
+## Notes
+
+- Alpha DoD (DESIGN §8): all phases P0–P6 merged + CI green. P5 (#605) pending merge after 0.0.38 publish.
+- Hook parity (codex/opencode/pi) = tracked v2 gap, documented in the matrix, not closed here.

packages/mosaic/framework/CONTRIBUTING.md

@@ -0,0 +1,185 @@
+# Contributing to the Mosaic Framework
+
+The Mosaic framework is the open-source agent-operating layer that deploys to
+`~/.config/mosaic/`. It is designed to be **forked and customized** — but the
+shared core must stay operator-neutral, deduplicated, and upgrade-safe. This
+guide is the contract for changing framework-owned files.
+
+> Governance model and layer rationale: `constitution/LAYER-MODEL.md` (source-only).
+> Requirements & phase history: `docs/design/framework-constitution/`.
+
+---
+
+## 1. The layer model (where does my change go?)
+
+| Layer  | What                                                          | Owner            | On upgrade                              | File(s)                                      |
+| ------ | ------------------------------------------------------------- | ---------------- | --------------------------------------- | -------------------------------------------- |
+| **L0** | Constitution — the non-negotiable law (hard gates)            | Framework        | **Overwritten**                         | `CONSTITUTION.md`                            |
+| **L1** | Standards & guides — how to do the work well                  | Framework        | Overwritten; user delta → `*.local.md`  | `STANDARDS.md`, `guides/*`                   |
+| **L2** | Persona (SOUL) — agent name, tone, role                       | User (init)      | **Never overwritten**                   | `SOUL.md` (+ optional `SOUL.local.md`)       |
+| **L3** | Operator (USER) — human identity, prefs, policy               | User (init)      | **Never overwritten**                   | `USER.md` (+ optional `USER.local.md`)       |
+| **L4** | Project / runtime mechanism — per-repo deltas; harness wiring | Repo / framework | Project user-owned; runtime overwritten | `<repo>/AGENTS.md`, `runtime/<h>/RUNTIME.md` |
+
+**The one sentence a user can rely on:** edit `SOUL.md` / `USER.md` and the
+`.local.md` overlays — they survive every upgrade. To change framework behavior,
+add a `.local.md` overlay; never edit a framework-owned file in place.
+
+---
+
+## 2. Operator hygiene (PII / secrets prohibition) — **blocking**
+
+Framework-owned files ship publicly. They **must not** contain:
+
+- Operator or personal identity (names, handles, pronouns, accessibility notes).
+- Private `$HOME` paths, private hostnames, or domains.
+- Secrets, tokens, or credentials (use `~/.config/mosaic/credentials.json`; the
+  hook URL soft-degrades via `${OPENBRAIN_URL}`).
+
+This is enforced by `tools/quality/scripts/verify-sanitized.sh`, wired **blocking**
+in CI (`.woodpecker/ci.yml`). It runs two rule classes: structural (private-`$HOME`
+defaults, dead paths, unrendered tokens) and a labeled current-contaminant denylist.
+Run it locally before pushing:
+
+```bash
+bash packages/mosaic/framework/tools/quality/scripts/verify-sanitized.sh
+```
+
+Operator-specific behavior belongs in **your** `SOUL.md`/`USER.md`/`*.local.md`,
+never in the shared core. (The "framework-PR firewall" in `CONSTITUTION.md` §4
+states this as law for agents opening framework PRs.)
+
+---
+
+## 3. Dedup rule — one source, everyone references it
+
+Hard gates live in **`CONSTITUTION.md` (L0) only**. `AGENTS.md`, `STANDARDS.md`,
+and every `runtime/<h>/RUNTIME.md` **reference** the law — they never restate it.
+Restating a gate is a defect: it creates two sources that drift. If you find a
+gate duplicated outside L0, delete the copy and point to L0.
+
+`AGENTS.md` is a thin dispatcher (load order + guide router + the tier-aware
+self-load). Keep it that way; new procedure goes in `guides/*` (on-demand), not
+in the resident core.
+
+---
+
+## 4. Resident line-count ceiling — **blocking**
+
+The framework-owned files injected by value (`CONSTITUTION.md`, `AGENTS.md`, each
+`runtime/<h>/RUNTIME.md`) are budgeted by **line count** — never by word count
+(a word cap forces paraphrasing the law, the exact drift vector we removed).
+
+```bash
+bash packages/mosaic/framework/tools/quality/scripts/check-resident-budget.sh
+```
+
+Wired blocking in CI. Gate **wording** stays intact; if a file legitimately needs
+more lines, raise its ceiling in the script deliberately (in the same PR, with
+rationale). The per-harness _total_ resident prompt (which also sums the user's
+`SOUL.md`/`USER.md`) is a `mosaic doctor` runtime advisory — CI cannot see user
+files, so it is out of CI scope by design (DESIGN §7).
+
+---
+
+## 5. Dual-installer parity rule
+
+Two installers seed and migrate `~/.config/mosaic/`:
+
+- **`framework/install.sh`** (bash) — the canonical installer.
+- **`packages/mosaic/src/config/file-adapter.ts`** (TS) — the wizard path.
+
+**Any change to seed lists, overwrite/preserve semantics, or migration MUST land
+in BOTH**, validated by the **shared fixture suite**:
+
+- `framework/tools/quality/scripts/test-install-migration.sh` (bash matrix)
+- `packages/mosaic/src/config/file-adapter.test.ts` (vitest)
+
+Both assert the same behavior: framework-owned files overwrite (backup-once to
+`*.pre-constitution.bak`); user-seeded files seed-if-absent; `SOUL.md`/`USER.md`/
+`*.local.md`/`credentials` are preserved. A change in one installer without the
+other (and its fixtures) is incomplete.
+
+---
+
+## 6. Adding a harness adapter
+
+A harness (runtime) is wired by:
+
+1. `runtime/<h>/RUNTIME.md` — **mechanism only** (subagent syntax, hook/MCP wiring,
+   injection method). No restated gates (see §3).
+2. Launcher emission in `src/commands/launch.ts` — how the composed contract reaches
+   the harness (system-prompt append vs. instructions file). Add the harness to the
+   `RuntimeName` union and the runtime-path map.
+3. `mosaic compose-contract <harness>` works automatically once the runtime path
+   exists (it composes base + `*.local.md` overlays for that harness).
+
+Then add a row to the compliance matrix (§8) and mark which gates are mechanical
+vs. resident-only for the new harness.
+
+---
+
+## 7. Re-contamination rule
+
+A green sanitization gate is not permanent. Before every PR:
+
+- Do not reintroduce operator identity, private paths, or secrets (§2).
+- Do not copy a gate out of L0 (§3).
+- Do not add an unrendered template token or a dead path to a shipped file.
+
+If `verify-sanitized.sh` goes red, that diff **is** your worklist — fix it, don't
+suppress it.
+
+---
+
+## 8. Harness × gate compliance matrix
+
+How each gate is enforced per harness. **Mechanical** = a hook/CI check the agent
+cannot bypass. **Resident** = injected contract prose (strong, but not a hard stop).
+**CI** = repo-side, harness-independent.
+
+| Gate / mechanism                              | Claude      | Codex            | OpenCode         | Pi               |
+| --------------------------------------------- | ----------- | ---------------- | ---------------- | ---------------- |
+| Contract injection (resident-by-value)        | append SP   | instructions     | `AGENTS.md`      | append SP        |
+| Operator overlays (`*.local`, composed)       | ✅          | ✅               | ✅               | ✅               |
+| Bare-launch self-load (Tier-3, read L0)       | ✅          | ✅               | ✅               | ✅               |
+| Sanitization (no PII) — `verify-sanitized`    | CI ✅       | CI ✅            | CI ✅            | CI ✅            |
+| Resident budget ceiling                       | CI ✅       | CI ✅            | CI ✅            | CI ✅            |
+| Migration parity (5-fixture, both installers) | CI ✅       | CI ✅            | CI ✅            | CI ✅            |
+| `no-memory-write` (PreToolUse hook)           | **mech ✅** | resident-only ⚠️ | resident-only ⚠️ | resident-only ⚠️ |
+| QA / typecheck (PostToolUse hooks)            | **mech ✅** | resident-only ⚠️ | resident-only ⚠️ | resident-only ⚠️ |
+| Native heartbeat (fleet `ps` model/status)    | sidecar     | sidecar          | sidecar          | **native ✅**    |
+
+⚠️ **Hook-parity gap (tracked, v2):** the mechanical PreToolUse/PostToolUse hooks
+exist for Claude Code only. On Codex/OpenCode/Pi those gates are currently enforced
+by the resident contract + CI, not by a per-tool hook. Closing hook parity is a
+**v2** item, not part of this alpha.
+
+---
+
+## 9. Known limitations (accepted residual risks)
+
+These are accepted with rationale (DESIGN §9); they are documented, not bugs:
+
+- **Bare-launch overlays are base-only.** A harness started without `mosaic` never
+  ran the composer, so `*.local.md` overlays are not applied. Mitigated by the
+  unconditional Tier-3 self-load + the `mosaic doctor` nudge in `AGENTS.md`; not
+  eliminated. Relaunch via `mosaic <harness>` to pick up overlays.
+- **Bare-launch drift is undetected by `mosaic doctor`** (the launcher never ran).
+- **Codex/OpenCode/Pi hook parity** is a tracked v2 gap (§8).
+- **Live-launch cross-harness verification** is v2; the alpha verifies the composer
+  by unit test (per-tier anchor + Tier-3 byte-equality), not a live launch.
+
+**Deferred to v2 (explicit):** `constitution/` deploy directory; capability JSON
+adapters; 3-way merge; `policy/*.md` composition; per-layer version stamps as a
+migration driver.
+
+---
+
+## 10. PR checklist
+
+- [ ] No operator identity / private paths / secrets (`verify-sanitized.sh` green).
+- [ ] No gate restated outside `CONSTITUTION.md` (§3).
+- [ ] Resident budget green (`check-resident-budget.sh`).
+- [ ] Seed/migration changes landed in **both** installers + shared fixtures (§5).
+- [ ] New harness → compliance-matrix row updated (§8).
+- [ ] `prettier --check` + `pnpm lint` + `pnpm typecheck` + `pnpm test` green.

packages/mosaic/framework/defaults/AGENTS.md

@@ -9,7 +9,10 @@ overwritten on upgrade. (Layer model: `constitution/LAYER-MODEL.md`.)
 1. Your context already includes `CONSTITUTION.md` + `USER.md` + the TOOLS index + the runtime
    contract (injected by `mosaic` launch) — do not re-read those. **If you were launched bare**
    (a harness started without `mosaic`, so the law is NOT in your context), read
-   `~/.config/mosaic/CONSTITUTION.md` now, before your first action.
+   `~/.config/mosaic/CONSTITUTION.md` now, before your first action. A bare launch also gets
+   **base contracts only** — operator overlays (`*.local.md`) are composed by the launcher, so if
+   `SOUL.local.md`/`USER.local.md`/`STANDARDS.local.md` exist, relaunch via `mosaic <harness>` (or run
+   `mosaic doctor`) to pick them up.
 2. Read `SOUL.md` (agent persona — small, once).
 3. Read project-local `AGENTS.md` / `CLAUDE.md` if present (these may only make behavior stricter).
 4. Read guides ONLY as triggered by the table below — pull role-relevant depth on demand, not up front.

packages/mosaic/framework/fleet/examples/coding.yaml

@@ -15,6 +15,10 @@ agents:
     runtime: claude
     class: orchestrator
     persistent_persona: true
+  - name: enhancer
+    runtime: claude
+    class: enhancer
+    persistent_persona: true
   - name: coder0
     runtime: pi
     class: implementer

packages/mosaic/framework/fleet/examples/general.yaml

@@ -15,6 +15,10 @@ agents:
     runtime: claude
     class: orchestrator
     persistent_persona: true
+  - name: enhancer
+    runtime: claude
+    class: enhancer
+    persistent_persona: true
   - name: generalist
     runtime: pi
     class: worker

packages/mosaic/framework/fleet/examples/hybrid.yaml

@@ -15,6 +15,10 @@ agents:
     runtime: claude
     class: orchestrator
     persistent_persona: true
+  - name: enhancer
+    runtime: claude
+    class: enhancer
+    persistent_persona: true
   - name: coder0
     runtime: pi
     class: implementer

packages/mosaic/framework/fleet/examples/research.yaml

@@ -15,6 +15,10 @@ agents:
     runtime: claude
     class: orchestrator
     persistent_persona: true
+  - name: enhancer
+    runtime: claude
+    class: enhancer
+    persistent_persona: true
   - name: researcher0
     runtime: pi
     class: researcher

packages/mosaic/framework/fleet/roles/enhancer.md

@@ -0,0 +1,41 @@
+# Enhancer — fleet role definition
+
+The **enhancer** is one half of the fleet's two-agent floor: every fleet runs, at
+minimum, an **orchestrator** and an **enhancer**. The orchestrator drives delivery;
+the enhancer makes the fleet _get better at delivering_ over time.
+
+It is a **core, always-on** agent (`class: enhancer`, `persistent_persona: true`),
+not an ephemeral per-lane worker.
+
+## Mandate
+
+The enhancer runs the fleet's **continuous-improvement loop**:
+
+1. **Monitor** fleet activity — agents, heartbeats, sessions, throughput, failures.
+2. **Analyze** for enhancements and optimizations — friction, gaps, recurring defects,
+   missing or broken tools, skill/harness shortfalls.
+3. **Plan** a remediation: a concrete improvement with rationale and expected effect.
+4. **Upgrade fleet capability — with the orchestrator** — tool creation/repair, skills,
+   harness improvements. The orchestrator owns fleet composition; the enhancer advises and
+   implements improvements to the _means of production_, not the product.
+5. **File upstream bug reports** to Mosaic Stack for real defects, so they flow back to the
+   framework for proper remediation rather than being patched over locally.
+6. **Recommend which agents are needed** — advise the orchestrator on roles to add/remove as
+   the mission evolves.
+
+## Boundaries
+
+- **Does NOT write product/source code.**
+- **Does NOT review code** (that is the code-review / security-review roles).
+- **Does NOT perform delivery tasks.**
+
+Improvement and diagnosis only. When the enhancer finds work that requires coding or review,
+it files it (bug report / recommendation) and the orchestrator materializes the right worker.
+
+## Why two, not one
+
+The orchestrator alone optimizes for _this_ delivery; the enhancer optimizes for _every future_
+delivery — self-healing the fleet's tools, skills, and harnesses, and routing real defects
+upstream. Together they are the irreducible core; every other role is added on demand.
+
+> Doctrine: `docs/fleet/north-star.md` (two-agent floor + role library).

packages/mosaic/framework/runtime/pi/mosaic-extension.ts

@@ -9,8 +9,16 @@
  *   4. Memory routing — remind agent to use ~/.config/mosaic/memory/
  */
 
-import type { ExtensionAPI } from '@mariozechner/pi-coding-agent';
+import type { ExtensionAPI, ExtensionContext } from '@earendil-works/pi-coding-agent';
-import { existsSync, readFileSync, writeFileSync, unlinkSync, mkdirSync } from 'node:fs';
+import { Type } from 'typebox';
+import {
+  existsSync,
+  readFileSync,
+  writeFileSync,
+  unlinkSync,
+  mkdirSync,
+  renameSync,
+} from 'node:fs';
 import { join, basename } from 'node:path';
 import { homedir } from 'node:os';
 import { execSync, spawnSync } from 'node:child_process';
@@ -25,6 +33,57 @@ const MOSAIC_HOME = process.env['MOSAIC_HOME'] ?? join(homedir(), '.config', 'mo
 // Helpers
 // ---------------------------------------------------------------------------
 
+// ---------------------------------------------------------------------------
+// Native heartbeat (fleet R14/R15)
+// ---------------------------------------------------------------------------
+// When this agent runs under the Mosaic fleet (MOSAIC_AGENT_NAME set), the
+// extension writes its OWN heartbeat in the same .hb contract `fleet ps` reads
+// (ts/pid/status[/model]) and touches a `.hb.native` precedence marker so the
+// shell sidecar defers. Native HB knows the real turn state (busy/ok), so it is
+// more accurate than the pane-PID-only sidecar fallback.
+const HB_AGENT_NAME = process.env['MOSAIC_AGENT_NAME'] ?? '';
+const HB_RUN_DIR = process.env['MOSAIC_HEARTBEAT_RUN_DIR'] ?? join(MOSAIC_HOME, 'fleet', 'run');
+const HB_INTERVAL_MS = (() => {
+  const s = Number.parseInt(process.env['MOSAIC_HEARTBEAT_INTERVAL'] ?? '', 10);
+  return Number.isFinite(s) && s > 0 ? s * 1000 : 15_000;
+})();
+
+function nativeHbEnabled(): boolean {
+  return HB_AGENT_NAME.length > 0;
+}
+
+function readModelId(ctx: ExtensionContext): string | null {
+  const m = ctx.model as unknown as { id?: string; name?: string } | undefined;
+  return m?.id ?? m?.name ?? null;
+}
+
+function writeNativeHeartbeat(status: 'ok' | 'busy', model: string | null): void {
+  if (!nativeHbEnabled()) return;
+  try {
+    mkdirSync(HB_RUN_DIR, { recursive: true });
+    const hb = join(HB_RUN_DIR, `${HB_AGENT_NAME}.hb`);
+    const lines = [`ts=${nowIso()}`, `pid=${process.pid}`, `status=${status}`];
+    if (model) lines.push(`model=${model}`);
+    const tmp = `${hb}.tmp.${process.pid}`;
+    writeFileSync(tmp, lines.join('\n') + '\n');
+    renameSync(tmp, hb); // atomic replace — fleet ps never reads a partial file
+    // Precedence marker: tells the shell sidecar that native HB is authoritative.
+    writeFileSync(join(HB_RUN_DIR, `${HB_AGENT_NAME}.hb.native`), nowIso() + '\n');
+  } catch {
+    // Best-effort: never let heartbeat I/O disrupt the Pi session.
+  }
+}
+
+function clearNativeMarker(): void {
+  if (!nativeHbEnabled()) return;
+  try {
+    const m = join(HB_RUN_DIR, `${HB_AGENT_NAME}.hb.native`);
+    if (existsSync(m)) unlinkSync(m); // native stopping — let the sidecar take over
+  } catch {
+    /* ignore */
+  }
+}
+
 function safeRead(filePath: string): string | null {
   try {
     return readFileSync(filePath, 'utf-8');
@@ -187,6 +246,9 @@ function buildMissionSummary(cwd: string, mission: ActiveMission): string {
 
 export default function register(pi: ExtensionAPI) {
   let sessionCwd = process.cwd();
+  let hbStatus: 'ok' | 'busy' = 'ok';
+  let hbModel: string | null = null;
+  let hbTimer: ReturnType<typeof setInterval> | null = null;
 
   // ── Session Start ─────────────────────────────────────────────────────
   pi.on('session_start', async (_event, ctx) => {
@@ -207,10 +269,39 @@ export default function register(pi: ExtensionAPI) {
     } else {
       ctx.ui.notify('Mosaic framework loaded', 'info');
     }
+
+    // Native heartbeat: write immediately, then on an interval. Idle = 'ok';
+    // turn_start/turn_end flip the status so `fleet ps` reflects real activity.
+    if (nativeHbEnabled()) {
+      hbModel = readModelId(ctx);
+      writeNativeHeartbeat('ok', hbModel);
+      hbTimer = setInterval(() => writeNativeHeartbeat(hbStatus, hbModel), HB_INTERVAL_MS);
+      if (typeof hbTimer.unref === 'function') hbTimer.unref();
+    }
   });
 
-  // ── Session End ───────────────────────────────────────────────────────
+  // ── Turn lifecycle → accurate busy/ok heartbeat ───────────────────────
-  pi.on('session_end', async (_event, _ctx) => {
+  pi.on('turn_start', async (_event, ctx) => {
+    hbStatus = 'busy';
+    hbModel = readModelId(ctx) ?? hbModel;
+    writeNativeHeartbeat('busy', hbModel);
+  });
+  pi.on('turn_end', async (_event, ctx) => {
+    hbStatus = 'ok';
+    hbModel = readModelId(ctx) ?? hbModel;
+    writeNativeHeartbeat('ok', hbModel);
+  });
+
+  // ── Session Shutdown ──────────────────────────────────────────────────
+  // (The pi API event is 'session_shutdown'; the prior 'session_end' handler
+  // never fired — fixed here so repo hooks + lock cleanup actually run.)
+  pi.on('session_shutdown', async (_event, _ctx) => {
+    if (hbTimer) {
+      clearInterval(hbTimer);
+      hbTimer = null;
+    }
+    clearNativeMarker();
+
     // Run repo session-end hook
     runRepoHook(sessionCwd, 'session-end');
 
@@ -252,4 +343,32 @@ export default function register(pi: ExtensionAPI) {
       }
     },
   });
+
+  // ── Register mosaic_mission_status tool (model-callable) ──────────────
+  // R14 "proper tool usage": give the agent a first-class tool to load its
+  // active Mosaic mission, milestone progress, task counts, and latest
+  // scratchpad — so it self-orients on in-flight work before planning,
+  // instead of shelling out or guessing. Mirrors the /mosaic-status command
+  // but returns the summary as tool output the LLM can read.
+  pi.registerTool({
+    name: 'mosaic_mission_status',
+    label: 'Mosaic Mission Status',
+    description:
+      'Return the active Mosaic mission, milestone progress, task counts, and latest scratchpad for the current project. Returns a note when no mission is active.',
+    promptSnippet: 'Read the active Mosaic mission + task state for the current project',
+    promptGuidelines: [
+      'Use mosaic_mission_status at the start of a session or task to load the active mission, milestone progress, and open tasks before planning work.',
+    ],
+    parameters: Type.Object({}),
+    async execute(_toolCallId, _params, _signal, _onUpdate, _ctx) {
+      const mission = detectMission(sessionCwd);
+      const text = mission
+        ? buildMissionSummary(sessionCwd, mission)
+        : 'No active Mosaic mission in this project.';
+      return {
+        content: [{ type: 'text', text }],
+        details: mission ? { ...mission } : { active: false },
+      };
+    },
+  });
 }

packages/mosaic/framework/tools/fleet/start-agent-session.sh

@@ -6,7 +6,7 @@ MOSAIC_TMUX_SOCKET=${MOSAIC_TMUX_SOCKET:-mosaic-factory}
 MOSAIC_AGENT_RUNTIME=${MOSAIC_AGENT_RUNTIME:-pi}
 MOSAIC_AGENT_WORKDIR=${MOSAIC_AGENT_WORKDIR:-$HOME}
 MOSAIC_AGENT_COMMAND=${MOSAIC_AGENT_COMMAND:-}
-MOSAIC_HEARTBEAT_RUN_DIR=${MOSAIC_HEARTBEAT_RUN_DIR:-$HOME/.config/mosaic/fleet/run}
+MOSAIC_HEARTBEAT_RUN_DIR=${MOSAIC_HEARTBEAT_RUN_DIR:-${MOSAIC_HOME:-$HOME/.config/mosaic}/fleet/run}
 MOSAIC_HEARTBEAT_INTERVAL=${MOSAIC_HEARTBEAT_INTERVAL:-15}
 
 if [ -z "$AGENT_NAME" ]; then
@@ -90,11 +90,18 @@ MOSAIC_RUNTIME_BIN_PREFIX=$(_build_runtime_bin_prefix)
 #
 # We build the snippet as a double-quoted here-string embedded in a printf call
 # to avoid nested quoting problems.
+#
+# MOSAIC_AGENT_NAME must also be exported INTO the pane: panes inherit the tmux
+# server environment (not this script's, and not the systemd unit's), so the
+# name would otherwise be empty in-pane and the runtime's native heartbeat
+# (which gates on MOSAIC_AGENT_NAME) would never fire. %q-quote it so it is a
+# safe single bash token regardless of the name's characters.
+AGENT_NAME_Q=$(printf '%q' "$AGENT_NAME")
 
 if [ -n "$MOSAIC_RUNTIME_BIN_PREFIX" ]; then
-  PANE_SHELL_SNIPPET="export PATH=\"${MOSAIC_RUNTIME_BIN_PREFIX}:\${PATH}\"; exec ${MOSAIC_AGENT_COMMAND}"
+  PANE_SHELL_SNIPPET="export MOSAIC_AGENT_NAME=${AGENT_NAME_Q}; export PATH=\"${MOSAIC_RUNTIME_BIN_PREFIX}:\${PATH}\"; exec ${MOSAIC_AGENT_COMMAND}"
 else
-  PANE_SHELL_SNIPPET="exec ${MOSAIC_AGENT_COMMAND}"
+  PANE_SHELL_SNIPPET="export MOSAIC_AGENT_NAME=${AGENT_NAME_Q}; exec ${MOSAIC_AGENT_COMMAND}"
 fi
 
 mkdir -p "$MOSAIC_AGENT_WORKDIR"
@@ -129,7 +136,7 @@ _start_heartbeat_sidecar() {
   # references to any variables from this script's environment.
   local sidecar_script
   sidecar_script=$(printf \
-    'hb=%s; pid=%s; iv=%s; mkdir -p "$(dirname "$hb")"; while kill -0 "$pid" 2>/dev/null; do tmp="$hb.tmp.$$"; printf "ts=%%s\npid=%%s\nstatus=ok\n" "$(date +%%Y-%%m-%%dT%%H:%%M:%%S%%z)" "$pid" > "$tmp" && mv "$tmp" "$hb"; sleep "$iv"; done' \
+    'hb=%q; pid=%q; iv=%q; mkdir -p "$(dirname "$hb")"; while kill -0 "$pid" 2>/dev/null; do nat="$hb.native"; if [ -f "$nat" ] && [ "$(( $(date +%%s) - $(stat -c %%Y "$nat" 2>/dev/null || echo 0) ))" -lt "$(( iv * 2 ))" ]; then sleep "$iv"; continue; fi; tmp="$hb.tmp.$$"; printf "ts=%%s\npid=%%s\nstatus=ok\n" "$(date +%%Y-%%m-%%dT%%H:%%M:%%S%%z)" "$pid" > "$tmp" && mv "$tmp" "$hb"; sleep "$iv"; done' \
     "$hb_file" "$pane_pid" "$interval")
 
   # setsid + disown ensures the sidecar survives this script exiting.

packages/mosaic/framework/tools/fleet/test-start-agent-session.sh

@@ -32,8 +32,15 @@ MOSAIC_AGENT_COMMAND='bash --noprofile --norc -i' \
   "$START" "$AGENT"
 
 tmux -L "$SOCKET" has-session -t "=$AGENT:0.0" || fail "agent session was not created"
+# Retry: pane_current_path briefly reflects the tmux server's cwd until the pane
+# process establishes its own cwd (the -c start dir). Poll until it settles.
+actual_dir=""
+for _ in $(seq 1 30); do
   actual_dir=$(tmux -L "$SOCKET" display-message -p -t "=$AGENT:0.0" '#{pane_current_path}')
-[ "$actual_dir" = "$WORKDIR" ] || fail "agent workdir mismatch: $actual_dir"
+  [ "$actual_dir" = "$WORKDIR" ] && break
+  sleep 0.1
+done
+[ "$actual_dir" = "$WORKDIR" ] || fail "agent workdir mismatch: $actual_dir (expected $WORKDIR)"
 
 # ── Test 2: idempotency (duplicate start prints 'already running') ─────────────
 MOSAIC_TMUX_SOCKET="$SOCKET" \

packages/mosaic/framework/tools/quality/scripts/check-resident-budget.sh

@@ -0,0 +1,93 @@
+#!/usr/bin/env bash
+# check-resident-budget.sh — resident line-count ceiling (R9 / DESIGN §7).
+#
+# Budgets the *container* (line count) of the framework-owned files that are
+# injected into every agent's context by value — the Constitution (L0), the
+# AGENTS dispatcher, and each runtime RUNTIME.md slice. Gate *wording* is never
+# capped (a word cap forces paraphrasing law — the exact drift vector P3 killed);
+# only the file's line count is bounded, so prose creep is caught in review.
+#
+# This is the CI-enforceable half of the budget. The per-harness *total* resident
+# prompt (which also includes user-generated SOUL.md/USER.md and the per-tier
+# slice) is summed by `mosaic doctor` as a runtime advisory — CI cannot see user
+# files, so it is deliberately out of scope here (DESIGN §7).
+#
+# Usage:  check-resident-budget.sh [--self-test]
+# Exit:   0 = all within budget · 1 = a file exceeds its ceiling · 2 = self-test failed
+set -uo pipefail
+
+FW="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)" # packages/mosaic/framework
+
+# Per-file ceilings (lines). Headroom above current counts; tighten as files settle.
+# Format: "<relative-path>:<max-lines>"
+CEILINGS=(
+  "defaults/CONSTITUTION.md:120"
+  "defaults/AGENTS.md:120"
+  "runtime/claude/RUNTIME.md:90"
+  "runtime/codex/RUNTIME.md:90"
+  "runtime/opencode/RUNTIME.md:90"
+  "runtime/pi/RUNTIME.md:90"
+)
+
+# check_file <abs-path> <max> → echoes "<n>"; returns 0 if n<=max, 1 otherwise.
+check_file() {
+  local path="$1" max="$2" n
+  n=$(wc -l <"$path" 2>/dev/null || echo 0)
+  n=$((n + 0))
+  echo "$n"
+  [ "$n" -le "$max" ]
+}
+
+run_budget() {
+  local fail=0 rel max abs n
+  printf '%-32s %8s %8s   %s\n' "FILE" "LINES" "CEILING" "STATUS"
+  for entry in "${CEILINGS[@]}"; do
+    rel="${entry%%:*}"
+    max="${entry##*:}"
+    abs="$FW/$rel"
+    if [ ! -f "$abs" ]; then
+      printf '%-32s %8s %8s   %s\n' "$rel" "-" "$max" "MISSING"
+      fail=1
+      continue
+    fi
+    n=$(check_file "$abs" "$max")
+    if [ "$n" -le "$max" ]; then
+      printf '%-32s %8s %8s   %s\n' "$rel" "$n" "$max" "ok"
+    else
+      printf '%-32s %8s %8s   %s\n' "$rel" "$n" "$max" "OVER BUDGET"
+      fail=1
+    fi
+  done
+  return "$fail"
+}
+
+self_test() {
+  local tmp rc
+  tmp=$(mktemp)
+  # 3 lines, ceiling 5 → within budget (rc 0)
+  printf 'a\nb\nc\n' >"$tmp"
+  check_file "$tmp" 5 >/dev/null
+  rc=$?
+  if [ "$rc" -ne 0 ]; then echo "self-test FAIL: under-budget file flagged"; rm -f "$tmp"; return 2; fi
+  # 6 lines, ceiling 5 → over budget (rc 1)
+  printf 'a\nb\nc\nd\ne\nf\n' >"$tmp"
+  check_file "$tmp" 5 >/dev/null
+  rc=$?
+  if [ "$rc" -ne 1 ]; then echo "self-test FAIL: over-budget file not flagged"; rm -f "$tmp"; return 2; fi
+  rm -f "$tmp"
+  echo "self-test OK"
+  return 0
+}
+
+if [ "${1:-}" = "--self-test" ]; then
+  self_test
+  exit $?
+fi
+
+if run_budget; then
+  echo "Resident budget: all framework-owned resident files within ceiling."
+  exit 0
+else
+  echo "Resident budget EXCEEDED — trim prose or raise the ceiling deliberately (see DESIGN §7)." >&2
+  exit 1
+fi

packages/mosaic/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mosaicstack/mosaic",
-  "version": "0.0.36",
+  "version": "0.0.39",
   "repository": {
     "type": "git",
     "url": "https://git.mosaicstack.dev/mosaicstack/stack.git",

packages/mosaic/src/cli.ts

@@ -26,6 +26,10 @@ import {
   checkForAllUpdates,
   formatAllPackagesTable,
   getInstallAllCommand,
+  runFrameworkReseed,
+  readRosterAgentNames,
+  buildRelaunchCommands,
+  FRAMEWORK_RESEED_PACKAGE,
 } from './runtime/update-checker.js';
 import { runWizard } from './wizard.js';
 import { ClackPrompter } from './prompter/clack-prompter.js';
@@ -404,7 +408,12 @@ program
   .command('update')
   .description('Check for and install Mosaic CLI updates')
   .option('--check', 'Check only, do not install')
-  .action(async (opts: { check?: boolean }) => {
+  .option(
+    '--no-reseed',
+    'Skip re-seeding framework files into ~/.config/mosaic after the CLI update',
+  )
+  .option('--relaunch', 'Restart durable fleet agents so the new launcher/runtime takes effect')
+  .action(async (opts: { check?: boolean; reseed?: boolean; relaunch?: boolean }) => {
     // checkForAllUpdates imported statically above
     const { execSync } = await import('node:child_process');
 
@@ -442,6 +451,51 @@ program
       console.error('\nUpdate failed. Try manually: bash tools/install.sh');
       process.exit(1);
     }
+
+    // F3-m3 / R13: the CLI is updated, but the framework files in
+    // ~/.config/mosaic/ are still the previous version. Re-seed them from the
+    // freshly-installed package so shipped launcher/runtime changes ACTIVATE.
+    // Only when the framework-bearing package itself updated.
+    const mosaicUpdated = outdated.some(
+      (r: { package: string }) => r.package === FRAMEWORK_RESEED_PACKAGE,
+    );
+    if (mosaicUpdated && opts.reseed !== false) {
+      console.log(
+        '\nRe-seeding framework files into ~/.config/mosaic (data-safe; keeps your edits)…',
+      );
+      const reseed = runFrameworkReseed();
+      if (reseed.ok) {
+        console.log('✔ Framework re-seeded.');
+        const agents = readRosterAgentNames();
+        if (agents.length > 0) {
+          if (opts.relaunch) {
+            console.log(
+              `\nRelaunching ${agents.length} fleet agent(s) to pick up the new runtime…`,
+            );
+            for (const restart of buildRelaunchCommands(agents)) {
+              try {
+                execSync(restart.join(' '), { stdio: 'inherit', timeout: 30_000 });
+              } catch {
+                console.error(`  ⚠ failed to restart agent — run: ${restart.join(' ')}`);
+              }
+            }
+            console.log('✔ Agents relaunched.');
+          } else {
+            console.log(
+              `\nℹ ${agents.length} fleet agent(s) are still running the previous runtime. ` +
+                'Restart them to activate the update:\n    mosaic update --relaunch   ' +
+                '(or: mosaic fleet restart <agent>)',
+            );
+          }
+        }
+      } else {
+        console.error(
+          `\n⚠ Framework re-seed skipped: ${reseed.reason ?? 'unknown'}.\n` +
+            '  Activate manually: bash "$(npm root -g)/@mosaicstack/mosaic/framework/install.sh" ' +
+            '(MOSAIC_SYNC_ONLY=1 MOSAIC_INSTALL_MODE=keep)',
+        );
+      }
+    }
   });
 
 // ─── wizard ─────────────────────────────────────────────────────────────

packages/mosaic/src/commands/compose-contract.spec.ts

@@ -0,0 +1,118 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync, readFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { composeContract } from './launch.js';
+
+/**
+ * Composer unit test (R7/R8/R9): asserts the launcher-composed runtime contract
+ *
+ *   - includes the per-tier anchors (CONSTITUTION / AGENTS / USER / runtime),
+ *   - keeps the CONSTITUTION block byte-equal to the on-disk file (Tier-3
+ *     byte-equality — the bare-launch fallback read must match what is injected),
+ *   - merges `*.local.md` operator overlays as deltas-by-value, and omits them
+ *     entirely when absent (base-only),
+ *   - selects the correct per-harness RUNTIME.md.
+ *
+ * `composeContract` takes `mosaicHome` as a param, so each test runs against an
+ * isolated fixture home. We also chdir to an empty temp cwd so the cwd-relative
+ * mission/PRD blocks contribute nothing (deterministic output).
+ */
+
+const CONSTITUTION = '# CONSTITUTION\n\nGATE-1: the non-negotiable law.\n';
+const AGENTS = '# Mosaic Agent Dispatcher\n\nLoad order + guide router.\n';
+const USER = '# operator\n\nName: Test Operator\n';
+const TOOLS = '# tools index\n';
+
+function makeHome(): { home: string; root: string } {
+  const root = mkdtempSync(join(tmpdir(), 'mosaic-compose-'));
+  const home = join(root, 'mosaic-home');
+  for (const h of ['claude', 'codex', 'opencode', 'pi']) {
+    mkdirSync(join(home, 'runtime', h), { recursive: true });
+    writeFileSync(join(home, 'runtime', h, 'RUNTIME.md'), `# ${h} runtime contract\n`);
+  }
+  writeFileSync(join(home, 'CONSTITUTION.md'), CONSTITUTION);
+  writeFileSync(join(home, 'AGENTS.md'), AGENTS);
+  writeFileSync(join(home, 'USER.md'), USER);
+  writeFileSync(join(home, 'TOOLS.md'), TOOLS);
+  return { home, root };
+}
+
+describe('composeContract — overlay composer', () => {
+  let fixture: ReturnType<typeof makeHome>;
+  let prevCwd: string;
+  let cwdDir: string;
+
+  beforeEach(() => {
+    fixture = makeHome();
+    prevCwd = process.cwd();
+    cwdDir = mkdtempSync(join(tmpdir(), 'mosaic-cwd-'));
+    process.chdir(cwdDir); // neutralize cwd-relative mission/PRD blocks
+  });
+
+  afterEach(() => {
+    process.chdir(prevCwd);
+    rmSync(fixture.root, { recursive: true, force: true });
+    rmSync(cwdDir, { recursive: true, force: true });
+  });
+
+  it('includes the per-tier anchors and the selected harness runtime', () => {
+    const out = composeContract('claude', fixture.home);
+    expect(out).toContain('GATE-1: the non-negotiable law.'); // L0
+    expect(out).toContain('Mosaic Agent Dispatcher'); // AGENTS
+    expect(out).toContain('# User Profile'); // USER header
+    expect(out).toContain('Name: Test Operator'); // USER body
+    expect(out).toContain('# Runtime-Specific Contract');
+    expect(out).toContain('# claude runtime contract');
+  });
+
+  it('keeps the CONSTITUTION block byte-equal to the on-disk file (Tier-3)', () => {
+    const out = composeContract('pi', fixture.home);
+    const onDisk = readFileSync(join(fixture.home, 'CONSTITUTION.md'), 'utf-8');
+    // The injected L0 must be a byte-equal substring of the composed blob, so a
+    // bare-launch fallback read of CONSTITUTION.md matches what was injected.
+    expect(out.includes(onDisk)).toBe(true);
+  });
+
+  it('is base-only when no *.local overlays exist', () => {
+    const out = composeContract('claude', fixture.home);
+    expect(out).not.toContain('# Operator Overlays');
+    expect(out).not.toContain('Operator Overlay (USER.local.md)');
+    expect(out).not.toContain('Persona Overlay');
+    expect(out).not.toContain('Standards Overlay');
+  });
+
+  it('merges USER.local.md directly under the operator profile', () => {
+    writeFileSync(join(fixture.home, 'USER.local.md'), 'Prefer terse status updates.\n');
+    const out = composeContract('claude', fixture.home);
+    expect(out).toContain('## Operator Overlay (USER.local.md)');
+    expect(out).toContain('Prefer terse status updates.');
+    // Overlay appears AFTER its base profile.
+    expect(out.indexOf('# User Profile')).toBeLessThan(
+      out.indexOf('## Operator Overlay (USER.local.md)'),
+    );
+  });
+
+  it('merges SOUL.local.md + STANDARDS.local.md as deltas in the Operator Overlays block', () => {
+    writeFileSync(join(fixture.home, 'SOUL.local.md'), 'Tone: dry and direct.\n');
+    writeFileSync(join(fixture.home, 'STANDARDS.local.md'), 'Require 90% coverage on auth code.\n');
+    const out = composeContract('claude', fixture.home);
+    expect(out).toContain('# Operator Overlays');
+    expect(out).toContain('## Persona Overlay (SOUL.local.md)');
+    expect(out).toContain('Tone: dry and direct.');
+    expect(out).toContain('## Standards Overlay (STANDARDS.local.md)');
+    expect(out).toContain('Require 90% coverage on auth code.');
+  });
+
+  it('ignores whitespace-only *.local overlays (no empty overlay section)', () => {
+    writeFileSync(join(fixture.home, 'SOUL.local.md'), '   \n\n');
+    const out = composeContract('claude', fixture.home);
+    expect(out).not.toContain('# Operator Overlays');
+  });
+
+  it('selects a different RUNTIME.md per harness', () => {
+    expect(composeContract('codex', fixture.home)).toContain('# codex runtime contract');
+    expect(composeContract('pi', fixture.home)).toContain('# pi runtime contract');
+    expect(composeContract('codex', fixture.home)).not.toContain('# pi runtime contract');
+  });
+});

packages/mosaic/src/commands/fleet.spec.ts

@@ -4,6 +4,7 @@ import { dirname, join, resolve } from 'node:path';
 import { Command } from 'commander';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 import {
+  addAgentToRoster,
   buildAgentSendCommand,
   buildAgentWatchAttachCommand,
   buildAgentWatchCommand,
@@ -13,11 +14,13 @@ import {
   buildEnableLingerCommand,
   buildFleetServiceCommand,
   buildSystemdEnableCommand,
+  buildSystemdDisableCommand,
   buildSystemdShowCommand,
   buildTmuxListPanesCommand,
   buildTmuxListSessionsCommand,
   classifySendResult,
   countOrchestrators,
+  countEnhancers,
   detectDrift,
   enableFleetUnits,
   FLEET_PROFILES,
@@ -35,9 +38,11 @@ import {
   parseTmuxListPanes,
   parseTmuxListSessions,
   registerFleetCommand,
+  removeAgentFromRoster,
   resolveFleetPaths,
   resolvePresetFilename,
   RUNTIME_ACCEPTABLE_COMMANDS,
+  serializeRosterToYaml,
   VERIFY_DEFAULT_TIMEOUT_MS,
   VERIFY_POLL_INTERVAL_MS,
   type AgentPsRow,
@@ -68,10 +73,12 @@ describe('registerFleetCommand', () => {
 
     expect(fleet).toBeDefined();
     expect(fleet!.commands.map((command) => command.name()).sort()).toEqual([
+      'add',
       'init',
       'install',
       'install-systemd',
       'ps',
+      'remove',
       'restart',
       'start',
       'status',
@@ -828,6 +835,17 @@ describe('fleet ps — heartbeat parsing', () => {
     expect(hb.pid).toBe(12345);
     expect(hb.status).toBe('ok');
     expect(hb.ageMs).toBe(10_000);
+    // No model= line in a legacy/sidecar heartbeat → model is null.
+    expect(hb.model).toBeNull();
+  });
+
+  it('parses a self-reported model id from a native heartbeat (model= line)', () => {
+    const ts = new Date(NOW - 5_000).toISOString();
+    const content = `ts=${ts}\npid=42\nstatus=busy\nmodel=openai-codex/gpt-5.5:high\n`;
+    const hb = parseHeartbeat(content, NOW);
+    expect(hb.model).toBe('openai-codex/gpt-5.5:high');
+    expect(hb.status).toBe('busy');
+    expect(hb.health).toBe('healthy');
   });
 
   it('reports stale when heartbeat is older than 3×interval', () => {
@@ -851,6 +869,23 @@ describe('fleet ps — heartbeat parsing', () => {
     expect(hb.health).toBe('unknown');
     expect(hb.ts).toBeNull();
   });
+
+  it('honors MOSAIC_HEARTBEAT_INTERVAL for the freshness threshold', () => {
+    const prev = process.env.MOSAIC_HEARTBEAT_INTERVAL;
+    try {
+      // A 60s-old beat is STALE at the default 15s interval (3x15 = 45s)...
+      const ts = new Date(NOW - 60_000).toISOString();
+      const content = `ts=${ts}\npid=1\nstatus=ok\n`;
+      delete process.env.MOSAIC_HEARTBEAT_INTERVAL;
+      expect(parseHeartbeat(content, NOW).health).toBe('stale');
+      // ...but HEALTHY when the operator widened the interval to 30s (3x30 = 90s).
+      process.env.MOSAIC_HEARTBEAT_INTERVAL = '30';
+      expect(parseHeartbeat(content, NOW).health).toBe('healthy');
+    } finally {
+      if (prev === undefined) delete process.env.MOSAIC_HEARTBEAT_INTERVAL;
+      else process.env.MOSAIC_HEARTBEAT_INTERVAL = prev;
+    }
+  });
 });
 
 describe('fleet ps — systemd show parsing', () => {
@@ -950,6 +985,129 @@ describe('fleet ps — drift detection', () => {
   });
 });
 
+describe('fleet-polish bundle — boot-survival symmetry', () => {
+  async function rosterHome(agents: string): Promise<string> {
+    const home = await tempDir();
+    await mkdir(join(home, 'fleet'), { recursive: true });
+    await writeFile(join(home, 'fleet', 'roster.yaml'), agents);
+    return home;
+  }
+
+  it('buildSystemdDisableCommand returns the systemctl --user disable array', () => {
+    expect(buildSystemdDisableCommand('mosaic-agent@coder0.service')).toEqual([
+      'systemctl',
+      '--user',
+      'disable',
+      'mosaic-agent@coder0.service',
+    ]);
+  });
+
+  it('fleet remove DISABLES the unit so a removed agent cannot resurrect on boot', async () => {
+    const home = await rosterHome(
+      [
+        'version: 1',
+        'transport: tmux',
+        'agents:',
+        '  - name: orchestrator',
+        '    runtime: pi',
+        '    class: orchestrator',
+        '  - name: coder0',
+        '    runtime: codex',
+        '    class: worker',
+      ].join('\n') + '\n',
+    );
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+    try {
+      await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+      expect(calls).toContainEqual([
+        'systemctl',
+        '--user',
+        'disable',
+        'mosaic-agent@coder0.service',
+      ]);
+      // stop must still happen too
+      expect(calls).toContainEqual(['systemctl', '--user', 'stop', 'mosaic-agent@coder0.service']);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  it('fleet add ENABLES the new agent unit for boot-survival', async () => {
+    const home = await rosterHome(
+      ['version: 1', 'transport: tmux', 'agents:', '  - name: coder0', '    runtime: codex'].join(
+        '\n',
+      ) + '\n',
+    );
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+    try {
+      await program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'add',
+        'coder1',
+        '--runtime',
+        'codex',
+        '--class',
+        'worker',
+        '--no-start',
+      ]);
+      expect(calls).toContainEqual([
+        'systemctl',
+        '--user',
+        'enable',
+        'mosaic-agent@coder1.service',
+      ]);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  it('fleet init --write enforces the two-agent floor (1 orchestrator + >=1 enhancer)', async () => {
+    // The general profile must yield exactly one orchestrator AND at least one
+    // enhancer; the guarantee is enforced (not just warned). Happy path writes cleanly.
+    const home = await tempDir();
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, {
+      runner: async () => ({ stdout: '', stderr: '', exitCode: 0 }),
+      mosaicHome: home,
+    });
+    try {
+      await program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'init',
+        '--profile',
+        'general',
+        '--write',
+      ]);
+      const written = await readFile(join(home, 'fleet', 'roster.yaml'), 'utf8');
+      const orchestrators = (written.match(/class:\s*orchestrator/g) ?? []).length;
+      const enhancers = (written.match(/class:\s*enhancer/g) ?? []).length;
+      expect(orchestrators).toBe(1);
+      expect(enhancers).toBeGreaterThanOrEqual(1);
+    } finally {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+});
+
 describe('fleet install — auto-enable units for boot-survival', () => {
   it('buildSystemdEnableCommand and buildEnableLingerCommand return correct command arrays', () => {
     expect(buildSystemdEnableCommand('mosaic-tmux-holder.service')).toEqual([
@@ -2155,47 +2313,63 @@ describe('fleet preset rosters', () => {
     },
   );
 
-  it('general preset: orchestrator + one generalist worker', async () => {
+  it('general preset: orchestrator + enhancer + one generalist worker', async () => {
     const roster = await loadFleetRoster(join(examplesDir, 'general.yaml'));
-    expect(roster.agents.map((a) => a.name)).toEqual(['orchestrator', 'generalist']);
+    expect(roster.agents.map((a) => a.name)).toEqual(['orchestrator', 'enhancer', 'generalist']);
     expect(roster.agents.find((a) => a.name === 'orchestrator')?.runtime).toBe('claude');
+    expect(roster.agents.find((a) => a.name === 'enhancer')?.className).toBe('enhancer');
     expect(roster.agents.find((a) => a.name === 'generalist')?.runtime).toBe('pi');
   });
 
-  it('coding preset: orchestrator + coder0 + coder1 + reviewer', async () => {
+  it('coding preset: orchestrator + enhancer + coder0 + coder1 + reviewer', async () => {
     const roster = await loadFleetRoster(join(examplesDir, 'coding.yaml'));
     expect(roster.agents.map((a) => a.name)).toEqual([
       'orchestrator',
+      'enhancer',
       'coder0',
       'coder1',
       'reviewer',
     ]);
   });
 
-  it('research preset: orchestrator + researcher0 + researcher1 + analyst', async () => {
+  it('research preset: orchestrator + enhancer + researcher0 + researcher1 + analyst', async () => {
     const roster = await loadFleetRoster(join(examplesDir, 'research.yaml'));
     expect(roster.agents.map((a) => a.name)).toEqual([
       'orchestrator',
+      'enhancer',
       'researcher0',
       'researcher1',
       'analyst',
     ]);
   });
 
-  it('hybrid preset: orchestrator + coder0 + researcher0 + reviewer', async () => {
+  it('hybrid preset: orchestrator + enhancer + coder0 + researcher0 + reviewer', async () => {
     const roster = await loadFleetRoster(join(examplesDir, 'hybrid.yaml'));
     expect(roster.agents.map((a) => a.name)).toEqual([
       'orchestrator',
+      'enhancer',
       'coder0',
       'researcher0',
       'reviewer',
     ]);
   });
 
+  it('every non-minimal preset carries an enhancer (two-agent floor)', async () => {
+    for (const preset of ['general', 'coding', 'research', 'hybrid'] as FleetProfile[]) {
+      const roster = await loadFleetRoster(join(examplesDir, `${preset}.yaml`));
+      expect(countOrchestrators(roster)).toBe(1);
+      expect(countEnhancers(roster)).toBeGreaterThanOrEqual(1);
+      expect(roster.agents.find((a) => a.className === 'enhancer')?.runtime).toBe('claude');
+    }
+  });
+
   it('worker agents in new presets use pi runtime with model_hint openai-codex/gpt-5.5:high', async () => {
     for (const preset of ['general', 'coding', 'research', 'hybrid'] as FleetProfile[]) {
       const roster = await loadFleetRoster(join(examplesDir, `${preset}.yaml`));
-      const workers = roster.agents.filter((a) => a.name !== 'orchestrator');
+      // Core agents (orchestrator + enhancer) run claude; only ephemeral workers are pi.
+      const workers = roster.agents.filter(
+        (a) => a.className !== 'orchestrator' && a.className !== 'enhancer',
+      );
       for (const worker of workers) {
         expect(worker.runtime).toBe('pi');
         expect(worker.modelHint).toBe('openai-codex/gpt-5.5:high');
@@ -2254,6 +2428,509 @@ describe('resolvePresetFilename', () => {
   });
 });
 
+// ---------------------------------------------------------------------------
+// Fleet Phase F5: orchestrator-mutable fleet — pure helper tests (R9)
+// ---------------------------------------------------------------------------
+
+describe('fleet add/remove — pure helpers', () => {
+  const baseRoster: FleetRoster = {
+    version: 1,
+    transport: 'tmux',
+    tmux: { socketName: 'mosaic-factory', holderSession: '_holder' },
+    defaults: { workingDirectory: '~/src' },
+    runtimes: { codex: { resetCommand: '/clear' } },
+    agents: [
+      { name: 'orchestrator', runtime: 'claude', className: 'orchestrator' },
+      { name: 'coder0', runtime: 'codex', className: 'worker' },
+    ],
+  };
+
+  it('addAgentToRoster appends a new agent and returns a new roster object', () => {
+    const newAgent = { name: 'reviewer0', runtime: 'pi', className: 'worker' };
+    const updated = addAgentToRoster(baseRoster, newAgent);
+    expect(updated.agents).toHaveLength(3);
+    expect(updated.agents[2]).toEqual(newAgent);
+    // immutable — original unchanged
+    expect(baseRoster.agents).toHaveLength(2);
+    expect(updated).not.toBe(baseRoster);
+  });
+
+  it('addAgentToRoster throws on duplicate name', () => {
+    expect(() =>
+      addAgentToRoster(baseRoster, { name: 'coder0', runtime: 'claude', className: 'worker' }),
+    ).toThrow('Agent "coder0" already exists in the fleet roster.');
+  });
+
+  it('addAgentToRoster throws on invalid name (invalid characters)', () => {
+    expect(() =>
+      addAgentToRoster(baseRoster, { name: 'bad name!', runtime: 'claude', className: 'worker' }),
+    ).toThrow('Invalid fleet agent name');
+  });
+
+  it('addAgentToRoster throws on empty name', () => {
+    expect(() =>
+      addAgentToRoster(baseRoster, { name: '', runtime: 'claude', className: 'worker' }),
+    ).toThrow('Invalid fleet agent name');
+  });
+
+  it('removeAgentFromRoster removes the agent and returns new roster', () => {
+    const updated = removeAgentFromRoster(baseRoster, 'coder0');
+    expect(updated.agents).toHaveLength(1);
+    expect(updated.agents[0]!.name).toBe('orchestrator');
+    // immutable
+    expect(baseRoster.agents).toHaveLength(2);
+    expect(updated).not.toBe(baseRoster);
+  });
+
+  it('removeAgentFromRoster throws when agent not found', () => {
+    expect(() => removeAgentFromRoster(baseRoster, 'nonexistent')).toThrow(
+      'Agent "nonexistent" is not in the fleet roster.',
+    );
+  });
+
+  it('removeAgentFromRoster throws when removing the sole orchestrator (guard)', () => {
+    const rosterWithOnlyOrch: FleetRoster = {
+      ...baseRoster,
+      agents: [{ name: 'orchestrator', runtime: 'claude', className: 'orchestrator' }],
+    };
+    expect(() => removeAgentFromRoster(rosterWithOnlyOrch, 'orchestrator')).toThrow(
+      'sole orchestrator',
+    );
+  });
+
+  it('removeAgentFromRoster allows removing an orchestrator when another remains', () => {
+    const rosterWithTwoOrchs: FleetRoster = {
+      ...baseRoster,
+      agents: [
+        { name: 'orchestrator', runtime: 'claude', className: 'orchestrator' },
+        { name: 'orchestrator2', runtime: 'claude', className: 'orchestrator' },
+        { name: 'coder0', runtime: 'codex', className: 'worker' },
+      ],
+    };
+    const updated = removeAgentFromRoster(rosterWithTwoOrchs, 'orchestrator');
+    expect(updated.agents.map((a) => a.name)).toEqual(['orchestrator2', 'coder0']);
+  });
+
+  it('countEnhancers counts enhancer-class agents (two-agent floor)', () => {
+    const roster: FleetRoster = {
+      ...baseRoster,
+      agents: [
+        { name: 'orchestrator', runtime: 'claude', className: 'orchestrator' },
+        { name: 'enhancer', runtime: 'claude', className: 'enhancer' },
+        { name: 'coder0', runtime: 'codex', className: 'worker' },
+      ],
+    };
+    expect(countEnhancers(roster)).toBe(1);
+    expect(countEnhancers(baseRoster)).toBe(0);
+  });
+
+  it('removeAgentFromRoster throws when removing the sole enhancer (two-agent floor)', () => {
+    const roster: FleetRoster = {
+      ...baseRoster,
+      agents: [
+        { name: 'orchestrator', runtime: 'claude', className: 'orchestrator' },
+        { name: 'enhancer', runtime: 'claude', className: 'enhancer' },
+      ],
+    };
+    expect(() => removeAgentFromRoster(roster, 'enhancer')).toThrow('sole enhancer');
+  });
+
+  it('removeAgentFromRoster allows removing an enhancer when another remains', () => {
+    const roster: FleetRoster = {
+      ...baseRoster,
+      agents: [
+        { name: 'orchestrator', runtime: 'claude', className: 'orchestrator' },
+        { name: 'enhancer', runtime: 'claude', className: 'enhancer' },
+        { name: 'enhancer2', runtime: 'claude', className: 'enhancer' },
+      ],
+    };
+    const updated = removeAgentFromRoster(roster, 'enhancer');
+    expect(updated.agents.map((a) => a.name)).toEqual(['orchestrator', 'enhancer2']);
+  });
+
+  it('serializeRosterToYaml produces YAML that round-trips through loadFleetRoster', async () => {
+    const yaml = serializeRosterToYaml(baseRoster);
+    expect(typeof yaml).toBe('string');
+    expect(yaml).toContain('version: 1');
+    expect(yaml).toContain('name: orchestrator');
+    expect(yaml).toContain('name: coder0');
+
+    // Round-trip: write to disk and re-load
+    const dir = await mkdtemp(join(tmpdir(), 'mosaic-fleet-'));
+    const rosterPath = join(dir, 'roster.yaml');
+    try {
+      await writeFile(rosterPath, yaml);
+      const loaded = await loadFleetRoster(rosterPath);
+      expect(loaded.agents.map((a) => a.name)).toEqual(['orchestrator', 'coder0']);
+      expect(loaded.tmux.socketName).toBe('mosaic-factory');
+      expect(loaded.agents[0]!.className).toBe('orchestrator');
+    } finally {
+      await rm(dir, { recursive: true, force: true });
+    }
+  });
+
+  it('serializeRosterToYaml round-trips optional fields (modelHint, workingDirectory)', async () => {
+    const rosterWithOptionals: FleetRoster = {
+      ...baseRoster,
+      agents: [
+        {
+          name: 'orchestrator',
+          runtime: 'claude',
+          className: 'orchestrator',
+          modelHint: 'claude-3-5-sonnet',
+          workingDirectory: '/tmp/work',
+          persistentPersona: true,
+          resetBetweenTasks: false,
+        },
+      ],
+    };
+    const yaml = serializeRosterToYaml(rosterWithOptionals);
+    expect(yaml).toContain('model_hint: claude-3-5-sonnet');
+    expect(yaml).toContain('working_directory: /tmp/work');
+    expect(yaml).toContain('persistent_persona: true');
+
+    const dir = await mkdtemp(join(tmpdir(), 'mosaic-fleet-'));
+    const rosterPath = join(dir, 'roster.yaml');
+    try {
+      await writeFile(rosterPath, yaml);
+      const loaded = await loadFleetRoster(rosterPath);
+      expect(loaded.agents[0]!.modelHint).toBe('claude-3-5-sonnet');
+      expect(loaded.agents[0]!.workingDirectory).toBe('/tmp/work');
+      expect(loaded.agents[0]!.persistentPersona).toBe(true);
+    } finally {
+      await rm(dir, { recursive: true, force: true });
+    }
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Fleet Phase F5: fleet add command tests
+// ---------------------------------------------------------------------------
+
+describe('fleet add command', () => {
+  let home: string;
+
+  afterEach(async () => {
+    if (home) {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  async function makeHome(agents = ['orchestrator']): Promise<string> {
+    const dir = await mkdtemp(join(tmpdir(), 'mosaic-fleet-add-'));
+    await mkdir(join(dir, 'fleet', 'agents'), { recursive: true });
+    const agentLines = agents.map((name) => {
+      const cls = name === 'orchestrator' ? 'orchestrator' : 'worker';
+      return `  - name: ${name}\n    runtime: claude\n    class: ${cls}`;
+    });
+    await writeFile(
+      join(dir, 'fleet', 'roster.yaml'),
+      ['version: 1', 'transport: tmux', 'agents:', ...agentLines].join('\n'),
+    );
+    return dir;
+  }
+
+  it('appends agent to roster file and writes env file', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync([
+      'node',
+      'mosaic',
+      'fleet',
+      'add',
+      'coder0',
+      '--runtime',
+      'codex',
+      '--class',
+      'worker',
+    ]);
+
+    const roster = await loadFleetRoster(join(home, 'fleet', 'roster.yaml'));
+    expect(roster.agents.map((a) => a.name)).toContain('coder0');
+
+    const envContent = await readFile(join(home, 'fleet', 'agents', 'coder0.env'), 'utf8');
+    expect(envContent).toContain('MOSAIC_AGENT_NAME=coder0');
+    expect(envContent).toContain('MOSAIC_AGENT_RUNTIME=codex');
+  });
+
+  it('--no-start skips the start command', async () => {
+    home = await makeHome();
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync([
+      'node',
+      'mosaic',
+      'fleet',
+      'add',
+      'coder0',
+      '--runtime',
+      'codex',
+      '--class',
+      'worker',
+      '--no-start',
+    ]);
+
+    // No start command should have been issued
+    const startCalls = calls.filter((c) => c.includes('start'));
+    expect(startCalls).toHaveLength(0);
+  });
+
+  it('without --no-start, issues start command for the new agent', async () => {
+    home = await makeHome();
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync([
+      'node',
+      'mosaic',
+      'fleet',
+      'add',
+      'coder0',
+      '--runtime',
+      'codex',
+      '--class',
+      'worker',
+    ]);
+
+    expect(calls).toContainEqual(['systemctl', '--user', 'start', 'mosaic-agent@coder0.service']);
+  });
+
+  it('throws when adding a duplicate agent name', async () => {
+    home = await makeHome(['orchestrator', 'coder0']);
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await expect(
+      program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'add',
+        'coder0',
+        '--runtime',
+        'codex',
+        '--class',
+        'worker',
+      ]),
+    ).rejects.toThrow('already exists');
+  });
+
+  it('throws when runtime is invalid', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await expect(
+      program.parseAsync([
+        'node',
+        'mosaic',
+        'fleet',
+        'add',
+        'coder0',
+        '--runtime',
+        'notaruntime',
+        '--class',
+        'worker',
+      ]),
+    ).rejects.toThrow('Invalid runtime');
+  });
+
+  it('accepts optional --model and --working-dir options', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync([
+      'node',
+      'mosaic',
+      'fleet',
+      'add',
+      'coder0',
+      '--runtime',
+      'claude',
+      '--class',
+      'worker',
+      '--model',
+      'claude-sonnet',
+      '--working-dir',
+      '/tmp/work',
+    ]);
+
+    const roster = await loadFleetRoster(join(home, 'fleet', 'roster.yaml'));
+    const agent = roster.agents.find((a) => a.name === 'coder0');
+    expect(agent?.modelHint).toBe('claude-sonnet');
+    expect(agent?.workingDirectory).toBe('/tmp/work');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Fleet Phase F5: fleet remove command tests
+// ---------------------------------------------------------------------------
+
+describe('fleet remove command', () => {
+  let home: string;
+
+  afterEach(async () => {
+    if (home) {
+      await rm(home, { recursive: true, force: true });
+    }
+  });
+
+  async function makeHome(): Promise<string> {
+    const dir = await mkdtemp(join(tmpdir(), 'mosaic-fleet-remove-'));
+    await mkdir(join(dir, 'fleet', 'agents'), { recursive: true });
+    await mkdir(join(dir, 'fleet', 'run'), { recursive: true });
+    await writeFile(
+      join(dir, 'fleet', 'roster.yaml'),
+      [
+        'version: 1',
+        'transport: tmux',
+        'agents:',
+        '  - name: orchestrator',
+        '    runtime: claude',
+        '    class: orchestrator',
+        '  - name: coder0',
+        '    runtime: codex',
+        '    class: worker',
+      ].join('\n'),
+    );
+    // Create env and heartbeat files for coder0
+    await writeFile(join(dir, 'fleet', 'agents', 'coder0.env'), 'MOSAIC_AGENT_NAME=coder0\n');
+    await writeFile(join(dir, 'fleet', 'run', 'coder0.hb'), 'ts=2026-01-01T00:00:00.000Z\n');
+    return dir;
+  }
+
+  it('removes agent from roster and writes back', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+
+    const roster = await loadFleetRoster(join(home, 'fleet', 'roster.yaml'));
+    expect(roster.agents.map((a) => a.name)).not.toContain('coder0');
+    expect(roster.agents.map((a) => a.name)).toContain('orchestrator');
+  });
+
+  it('stop is called before roster write (stop is the first runner call)', async () => {
+    home = await makeHome();
+    const calls: string[][] = [];
+    const runner: CommandRunner = async (command, args) => {
+      calls.push([command, ...args]);
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+
+    expect(calls[0]).toEqual(['systemctl', '--user', 'stop', 'mosaic-agent@coder0.service']);
+  });
+
+  it('stop failure is non-fatal — warns but still removes from roster', async () => {
+    home = await makeHome();
+    const stderrMessages: string[] = [];
+    const stderrSpy = vi.spyOn(process.stderr, 'write').mockImplementation((msg) => {
+      stderrMessages.push(String(msg));
+      return true;
+    });
+
+    const runner: CommandRunner = async (command, args) => {
+      if (args.includes('stop')) {
+        return { stdout: '', stderr: 'unit not found', exitCode: 5 };
+      }
+      return { stdout: '', stderr: '', exitCode: 0 };
+    };
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    try {
+      // Must not reject
+      await expect(
+        program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']),
+      ).resolves.toBeDefined();
+
+      // Agent should be removed from roster despite stop failure
+      const roster = await loadFleetRoster(join(home, 'fleet', 'roster.yaml'));
+      expect(roster.agents.map((a) => a.name)).not.toContain('coder0');
+
+      // Warning must have been emitted
+      expect(stderrMessages.join('')).toMatch(/Warning/);
+    } finally {
+      stderrSpy.mockRestore();
+    }
+  });
+
+  it('--keep-files skips env file deletion', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0', '--keep-files']);
+
+    // Env file should still exist
+    const envContent = await readFile(join(home, 'fleet', 'agents', 'coder0.env'), 'utf8');
+    expect(envContent).toContain('MOSAIC_AGENT_NAME=coder0');
+  });
+
+  it('env file is removed by default (no --keep-files)', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+
+    await expect(readFile(join(home, 'fleet', 'agents', 'coder0.env'), 'utf8')).rejects.toThrow();
+  });
+
+  it('removing the sole orchestrator throws with a clear error about the guard', async () => {
+    home = await makeHome();
+    const runner: CommandRunner = async () => ({ stdout: '', stderr: '', exitCode: 0 });
+    const program = new Command();
+    program.exitOverride();
+    registerFleetCommand(program, { runner, mosaicHome: home });
+
+    // First remove the worker so only the orchestrator remains
+    await program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'coder0']);
+
+    // Now attempt to remove the sole orchestrator
+    await expect(
+      program.parseAsync(['node', 'mosaic', 'fleet', 'remove', 'orchestrator']),
+    ).rejects.toThrow('sole orchestrator');
+  });
+});
+
 describe('fleet init wizard', () => {
   let cleanup: string | undefined;
 
@@ -2404,3 +3081,33 @@ describe('fleet init wizard', () => {
     expect(content).toContain('name: coder0');
   });
 });
+
+describe('fleet ps — heartbeat path resolution', () => {
+  const savedRunDir = process.env.MOSAIC_HEARTBEAT_RUN_DIR;
+  const savedHome = process.env.MOSAIC_HOME;
+  afterEach(() => {
+    if (savedRunDir === undefined) delete process.env.MOSAIC_HEARTBEAT_RUN_DIR;
+    else process.env.MOSAIC_HEARTBEAT_RUN_DIR = savedRunDir;
+    if (savedHome === undefined) delete process.env.MOSAIC_HOME;
+    else process.env.MOSAIC_HOME = savedHome;
+  });
+
+  it('honors MOSAIC_HEARTBEAT_RUN_DIR (matches the writer sidecar override)', () => {
+    process.env.MOSAIC_HEARTBEAT_RUN_DIR = '/run/hb';
+    expect(heartbeatPath('agent-x', '/any/home')).toBe(join('/run/hb', 'agent-x.hb'));
+  });
+
+  it('honors MOSAIC_HOME when no explicit mosaicHome is given', () => {
+    delete process.env.MOSAIC_HEARTBEAT_RUN_DIR;
+    process.env.MOSAIC_HOME = '/custom/mhome';
+    expect(heartbeatPath('agent-y')).toBe(join('/custom/mhome', 'fleet', 'run', 'agent-y.hb'));
+  });
+
+  it('falls back to <mosaicHome>/fleet/run by default', () => {
+    delete process.env.MOSAIC_HEARTBEAT_RUN_DIR;
+    delete process.env.MOSAIC_HOME;
+    expect(heartbeatPath('agent-z', '/home/u/.config/mosaic')).toBe(
+      join('/home/u/.config/mosaic', 'fleet', 'run', 'agent-z.hb'),
+    );
+  });
+});

packages/mosaic/src/commands/fleet.ts

@@ -1,5 +1,5 @@
 import { constants } from 'node:fs';
-import { access, chmod, copyFile, mkdir, readFile, writeFile } from 'node:fs/promises';
+import { access, chmod, copyFile, mkdir, readFile, unlink, writeFile } from 'node:fs/promises';
 import { homedir, hostname, userInfo } from 'node:os';
 import { dirname, join, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
@@ -152,13 +152,16 @@ export function resolveFleetPaths(mosaicHome = defaultMosaicHome()): FleetPaths
 }
 
 function defaultMosaicHome(): string {
-  return join(homedir(), '.config', 'mosaic');
+  // Honor MOSAIC_HOME so the reader matches the writer sidecar (and the launcher),
+  // even when MOSAIC_HOME is set in the shell without an explicit --mosaic-home flag.
+  return process.env.MOSAIC_HOME ?? join(homedir(), '.config', 'mosaic');
 }
 
 function assertDefaultMosaicHomeForSystemd(mosaicHome: string): void {
-  if (resolve(mosaicHome) !== resolve(defaultMosaicHome())) {
+  const literalHome = join(homedir(), '.config', 'mosaic');
+  if (resolve(mosaicHome) !== resolve(literalHome)) {
     throw new Error(
-      `install-systemd only supports the default Mosaic home (${defaultMosaicHome()}) because the user systemd units use %h/.config/mosaic paths.`,
+      `install-systemd only supports the default Mosaic home (${literalHome}) because the user systemd units use %h/.config/mosaic paths.`,
     );
   }
 }
@@ -224,6 +227,15 @@ export function buildSystemdEnableCommand(unit: string): string[] {
   return ['systemctl', '--user', 'enable', unit];
 }
 
+/**
+ * Returns the systemctl --user disable command for a given unit.
+ * Used by `fleet remove` so a removed agent's enabled unit cannot resurrect on
+ * boot pointing at deleted config (boot-survival symmetry with enable-on-add).
+ */
+export function buildSystemdDisableCommand(unit: string): string[] {
+  return ['systemctl', '--user', 'disable', unit];
+}
+
 /**
  * Returns the loginctl enable-linger command for a given user.
  * Linger allows user systemd services to survive logout.
@@ -368,6 +380,16 @@ export function buildAgentTailCommand(
 // ---------------------------------------------------------------------------
 
 export const HEARTBEAT_INTERVAL_MS = 15_000;
+
+/**
+ * Heartbeat interval in ms, honoring MOSAIC_HEARTBEAT_INTERVAL (seconds) so the
+ * `fleet ps` freshness threshold matches the writer sidecar's actual cadence
+ * (start-agent-session.sh). Falls back to HEARTBEAT_INTERVAL_MS (15s).
+ */
+export function heartbeatIntervalMs(): number {
+  const sec = Number.parseInt(process.env.MOSAIC_HEARTBEAT_INTERVAL ?? '', 10);
+  return Number.isFinite(sec) && sec > 0 ? sec * 1000 : HEARTBEAT_INTERVAL_MS;
+}
 export const HEARTBEAT_HEALTHY_MULTIPLIER = 3;
 
 export interface HeartbeatInfo {
@@ -377,6 +399,8 @@ export interface HeartbeatInfo {
   /** healthy | stale | unknown */
   health: 'healthy' | 'stale' | 'unknown';
   ageMs: number | null;
+  /** Model id the runtime self-reported in its heartbeat (native HB only), else null. */
+  model: string | null;
 }
 
 export interface AgentPsRow {
@@ -465,7 +489,10 @@ export function parseTmuxListSessions(output: string): string[] {
  * Returns the heartbeat file path for an agent.
  */
 export function heartbeatPath(agentName: string, mosaicHome = defaultMosaicHome()): string {
-  return join(mosaicHome, 'fleet', 'run', `${agentName}.hb`);
+  // Honor MOSAIC_HEARTBEAT_RUN_DIR (the writer sidecar's override); otherwise the
+  // canonical <mosaicHome>/fleet/run. Keeps reader and writer on the same path.
+  const runDir = process.env.MOSAIC_HEARTBEAT_RUN_DIR ?? join(mosaicHome, 'fleet', 'run');
+  return join(runDir, `${agentName}.hb`);
 }
 
 /**
@@ -474,15 +501,17 @@ export function heartbeatPath(agentName: string, mosaicHome = defaultMosaicHome(
  *   ts=<iso8601>
  *   pid=<pid>
  *   status=<ok|busy>
+ *   model=<model-id>   (optional — native runtime heartbeats self-report it)
  */
 export function parseHeartbeat(content: string | null, nowMs = Date.now()): HeartbeatInfo {
   if (content === null) {
-    return { ts: null, pid: null, status: null, health: 'unknown', ageMs: null };
+    return { ts: null, pid: null, status: null, health: 'unknown', ageMs: null, model: null };
   }
   const lines = content.split('\n');
   let ts: Date | null = null;
   let pid: number | null = null;
   let status: 'ok' | 'busy' | null = null;
+  let model: string | null = null;
   for (const line of lines) {
     const [key, ...rest] = line.split('=');
     const val = rest.join('=').trim();
@@ -494,16 +523,18 @@ export function parseHeartbeat(content: string | null, nowMs = Date.now()): Hear
       if (Number.isFinite(n)) pid = n;
     } else if (key === 'status' && (val === 'ok' || val === 'busy')) {
       status = val;
+    } else if (key === 'model' && val) {
+      model = val;
     }
   }
-  const thresholdMs = HEARTBEAT_INTERVAL_MS * HEARTBEAT_HEALTHY_MULTIPLIER;
+  const thresholdMs = heartbeatIntervalMs() * HEARTBEAT_HEALTHY_MULTIPLIER;
   let health: 'healthy' | 'stale' | 'unknown' = 'unknown';
   let ageMs: number | null = null;
   if (ts !== null) {
     ageMs = nowMs - ts.getTime();
     health = ageMs <= thresholdMs ? 'healthy' : 'stale';
   }
-  return { ts, pid, status, health, ageMs };
+  return { ts, pid, status, health, ageMs, model };
 }
 
 /**
@@ -850,20 +881,33 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
       await mkdir(dirname(destination), { recursive: true });
       await writeFile(destination, content);
 
-      // Validate: exactly one orchestrator required (R5) — friendly summary on success.
+      // Guarantee the two-agent floor: exactly one orchestrator AND at least
+      // one enhancer for every profile except the sanctioned no-orchestrator
+      // `minimal` preset. A mismatch means a corrupted/edited preset — fail hard
+      // rather than write a malformed fleet.
       const written = await loadFleetRoster(destination);
       const orchCount = countOrchestrators(written);
-      if (orchCount !== 1) {
+      const enhancerCount = countEnhancers(written);
-        process.stderr.write(
+      if (profile === 'minimal') {
-          `Warning: fleet roster at ${destination} has ${orchCount} orchestrator agent(s) (expected exactly 1).\n`,
-        );
         console.log(
-          `Initialized ${profile} fleet: ${written.agents.length} agent(s). Next: mosaic fleet install`,
+          `Initialized ${profile} fleet: ${written.agents.length} agent(s) (no orchestrator). Next: mosaic fleet install`,
+        );
+      } else if (orchCount !== 1) {
+        throw new Error(
+          `Fleet init failed: the "${profile}" roster has ${orchCount} orchestrator agent(s), ` +
+            `expected exactly 1 (R5). The preset may be corrupted — re-install the framework.`,
+        );
+      } else if (enhancerCount < 1) {
+        throw new Error(
+          `Fleet init failed: the "${profile}" roster has no enhancer agent. Every fleet keeps an ` +
+            `orchestrator + enhancer minimum (two-agent floor). The preset may be corrupted — ` +
+            `re-install the framework.`,
         );
       } else {
-        const workerCount = written.agents.length - 1;
+        const workerCount = written.agents.length - 1 - enhancerCount;
         console.log(
-          `Initialized ${profile} fleet: 1 orchestrator + ${workerCount} agent(s). Next: mosaic fleet install`,
+          `Initialized ${profile} fleet: 1 orchestrator + ${enhancerCount} enhancer(s) + ` +
+            `${workerCount} worker(s). Next: mosaic fleet install`,
         );
       }
     });
@@ -1107,6 +1151,7 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
         'PID'.padEnd(8),
         'IDLE'.padEnd(8),
         'HB'.padEnd(12),
+        'MODEL'.padEnd(22),
         'FLAGS',
       ].join(' ');
       console.log(header);
@@ -1121,6 +1166,7 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
           row.heartbeat.ageMs !== null
             ? `${Math.round(row.heartbeat.ageMs / 1000)}s/${row.heartbeat.health}`
             : `unknown`;
+        const model = row.heartbeat.model ?? '-';
         const flags: string[] = [];
         if (!row.managed) flags.push('UNMANAGED');
         if (row.driftFlag) flags.push('DRIFT');
@@ -1137,12 +1183,157 @@ export function registerFleetCommand(program: Command, deps: FleetCommandDeps =
             pid.padEnd(8),
             idle.padEnd(8),
             hbAge.padEnd(12),
+            model.padEnd(22),
             flags.join(','),
           ].join(' '),
         );
       }
     });
 
+  cmd
+    .command('add <name>')
+    .description('Add a new agent to the fleet roster and optionally start it')
+    .requiredOption('--runtime <runtime>', `Agent runtime (${VALID_FLEET_RUNTIMES.join(', ')})`)
+    .requiredOption('--class <class>', 'Agent class (e.g. worker, orchestrator, canary)')
+    .option('--model <hint>', 'Model hint for the agent')
+    .option('--working-dir <path>', 'Working directory for the agent')
+    .option('--no-start', 'Skip starting the agent after adding')
+    .action(
+      async (
+        name: string,
+        opts: {
+          runtime: string;
+          class: string;
+          model?: string;
+          workingDir?: string;
+          start: boolean;
+        },
+      ) => {
+        if (!VALID_FLEET_RUNTIMES.includes(opts.runtime)) {
+          throw new Error(
+            `Invalid runtime "${opts.runtime}". Valid runtimes: ${VALID_FLEET_RUNTIMES.join(', ')}.`,
+          );
+        }
+        const commandOpts = cmd.opts<{ mosaicHome: string; roster?: string }>();
+        const activePaths = resolveFleetPaths(commandOpts.mosaicHome);
+        const rosterPath = await resolveRosterPath(commandOpts.mosaicHome, commandOpts.roster);
+        const roster = await loadFleetRoster(rosterPath);
+
+        const newAgent: FleetAgent = {
+          name,
+          runtime: opts.runtime,
+          className: opts.class,
+          ...(opts.workingDir !== undefined && { workingDirectory: opts.workingDir }),
+          ...(opts.model !== undefined && { modelHint: opts.model }),
+        };
+
+        const updatedRoster = addAgentToRoster(roster, newAgent);
+        await writeFile(rosterPath, serializeRosterToYaml(updatedRoster));
+
+        const envPath = join(activePaths.agentEnvDir, `${name}.env`);
+        const existingEnv = (await canRead(envPath)) ? await readFile(envPath, 'utf8') : undefined;
+        await mkdir(activePaths.agentEnvDir, { recursive: true });
+        await writeFile(
+          envPath,
+          mergeAgentEnv(generateAgentEnv(updatedRoster, newAgent), existingEnv),
+        );
+
+        console.log(`Added ${name} (${opts.runtime}/${opts.class}) to the fleet.`);
+
+        // Enable the unit for boot-survival (non-fatal) — symmetry with
+        // disable-on-remove. Independent of --start so a queued agent still
+        // survives a reboot once its unit exists.
+        try {
+          const enableResult = await runner(
+            ...splitCommand(buildSystemdEnableCommand(`mosaic-agent@${name}.service`)),
+          );
+          if (enableResult.exitCode !== 0) {
+            process.stderr.write(
+              `Warning: could not enable mosaic-agent@${name}.service: ${enableResult.stderr || enableResult.stdout || 'non-zero exit'}\n`,
+            );
+          }
+        } catch (err) {
+          process.stderr.write(
+            `Warning: enable command failed for ${name}: ${err instanceof Error ? err.message : String(err)}\n`,
+          );
+        }
+
+        if (opts.start !== false) {
+          await runChecked(runner, buildFleetServiceCommand('start', name));
+          console.log(`Started mosaic-agent@${name}.service.`);
+        } else {
+          console.log(`Agent queued (--no-start); run: mosaic fleet start ${name}`);
+        }
+      },
+    );
+
+  cmd
+    .command('remove <name>')
+    .description('Remove an agent from the fleet roster')
+    .option('--keep-files', 'Skip deleting env and heartbeat files')
+    .action(async (name: string, opts: { keepFiles?: boolean }) => {
+      const commandOpts = cmd.opts<{ mosaicHome: string; roster?: string }>();
+      const activePaths = resolveFleetPaths(commandOpts.mosaicHome);
+      const rosterPath = await resolveRosterPath(commandOpts.mosaicHome, commandOpts.roster);
+      const roster = await loadFleetRoster(rosterPath);
+
+      // Guard: throws if removing leaves 0 orchestrators or agent not in roster
+      const updatedRoster = removeAgentFromRoster(roster, name);
+
+      // Stop agent (non-fatal)
+      try {
+        const stopResult = await runner(...splitCommand(buildFleetServiceCommand('stop', name)));
+        if (stopResult.exitCode !== 0) {
+          process.stderr.write(
+            `Warning: could not stop mosaic-agent@${name}.service: ${stopResult.stderr || stopResult.stdout || 'non-zero exit'}\n`,
+          );
+        }
+      } catch (err) {
+        process.stderr.write(
+          `Warning: stop command failed for ${name}: ${err instanceof Error ? err.message : String(err)}\n`,
+        );
+      }
+
+      // Disable the unit (non-fatal) so an enabled instance cannot resurrect on
+      // boot pointing at the now-deleted config — boot-survival symmetry with
+      // enable-on-add. Skipped only when --keep-files keeps the config in place.
+      if (!opts.keepFiles) {
+        try {
+          const disableResult = await runner(
+            ...splitCommand(buildSystemdDisableCommand(`mosaic-agent@${name}.service`)),
+          );
+          if (disableResult.exitCode !== 0) {
+            process.stderr.write(
+              `Warning: could not disable mosaic-agent@${name}.service: ${disableResult.stderr || disableResult.stdout || 'non-zero exit'}\n`,
+            );
+          }
+        } catch (err) {
+          process.stderr.write(
+            `Warning: disable command failed for ${name}: ${err instanceof Error ? err.message : String(err)}\n`,
+          );
+        }
+      }
+
+      // Write updated roster
+      await writeFile(rosterPath, serializeRosterToYaml(updatedRoster));
+
+      // Delete env and heartbeat files (best-effort, non-fatal)
+      if (!opts.keepFiles) {
+        try {
+          await unlink(join(activePaths.agentEnvDir, `${name}.env`));
+        } catch {
+          // best-effort
+        }
+        try {
+          await unlink(heartbeatPath(name, activePaths.mosaicHome));
+        } catch {
+          // best-effort
+        }
+      }
+
+      console.log(`Removed ${name} from the fleet.`);
+    });
+
   return cmd;
 }
 
@@ -1322,15 +1513,19 @@ export function registerFleetAgentCommands(
 
       await runChecked(runner, buildAgentWatchCreateViewerCommand(agent, viewerName, socketName));
 
+      let exitCode = 0;
+      try {
         const [bin, args] = splitCommand(buildAgentWatchAttachCommand(viewerName, socketName));
-      const exitCode = await iRunner(bin, args);
+        exitCode = await iRunner(bin, args);
-
+      } finally {
-      // Best-effort cleanup of the viewer session regardless of how the user detached.
+        // ALWAYS clean up the viewer session — even if attach threw or the process was
-      // Errors here are intentionally suppressed — the agent session is unaffected.
+        // interrupted — so stale grouped *-watch-* sessions never accumulate. Errors here
+        // are intentionally suppressed; the agent session is unaffected.
         const killResult = await runner(
           ...splitCommand(buildAgentWatchKillViewerCommand(viewerName, socketName)),
         );
-      void killResult; // result is intentionally ignored
+        void killResult;
+      }
 
       if (exitCode !== 0) {
         process.exitCode = exitCode;
@@ -1759,6 +1954,123 @@ export function countOrchestrators(roster: FleetRoster): number {
   return roster.agents.filter((a) => a.className === 'orchestrator').length;
 }
 
+/**
+ * Count enhancer agents in a parsed roster. The two-agent floor (north-star)
+ * requires every non-minimal fleet to carry at least one enhancer alongside the
+ * sole orchestrator.
+ */
+export function countEnhancers(roster: FleetRoster): number {
+  return roster.agents.filter((a) => a.className === 'enhancer').length;
+}
+
+/** Valid runtime identifiers for fleet agents. */
+export const VALID_FLEET_RUNTIMES: readonly string[] = [
+  'pi',
+  'claude',
+  'codex',
+  'opencode',
+  'dogfood',
+];
+
+/**
+ * Add a new agent to a fleet roster (immutable — returns a new FleetRoster).
+ * Throws on invalid name, duplicate name.
+ */
+export function addAgentToRoster(roster: FleetRoster, agent: FleetAgent): FleetRoster {
+  if (!agent.name || !/^[A-Za-z0-9_.-]+$/.test(agent.name)) {
+    throw new Error(`Invalid fleet agent name: ${agent.name || '<empty>'}`);
+  }
+  if (roster.agents.some((a) => a.name === agent.name)) {
+    throw new Error(`Agent "${agent.name}" already exists in the fleet roster.`);
+  }
+  return {
+    ...roster,
+    agents: [...roster.agents, agent],
+  };
+}
+
+/**
+ * Remove an agent from a fleet roster (immutable — returns a new FleetRoster).
+ * Throws if the agent is not found, or if removal would leave zero orchestrators.
+ */
+export function removeAgentFromRoster(roster: FleetRoster, name: string): FleetRoster {
+  const agent = roster.agents.find((a) => a.name === name);
+  if (!agent) {
+    throw new Error(`Agent "${name}" is not in the fleet roster.`);
+  }
+  const remaining = roster.agents.filter((a) => a.name !== name);
+  const remainingOrchCount = remaining.filter((a) => a.className === 'orchestrator').length;
+  if (remainingOrchCount === 0 && agent.className === 'orchestrator') {
+    throw new Error(
+      `Cannot remove agent "${name}": it is the sole orchestrator. Add another orchestrator first (R5).`,
+    );
+  }
+  // Two-agent floor: never drop the last enhancer (the continuous-improvement
+  // loop). Symmetric with the sole-orchestrator guard.
+  const remainingEnhancerCount = remaining.filter((a) => a.className === 'enhancer').length;
+  if (remainingEnhancerCount === 0 && agent.className === 'enhancer') {
+    throw new Error(
+      `Cannot remove agent "${name}": it is the sole enhancer. Every fleet keeps at least one ` +
+        `enhancer (two-agent floor). Add another enhancer first.`,
+    );
+  }
+  return {
+    ...roster,
+    agents: remaining,
+  };
+}
+
+/**
+ * Serialize a FleetRoster to YAML text (snake_case keys).
+ * The output is parseable by loadFleetRoster.
+ */
+export function serializeRosterToYaml(roster: FleetRoster): string {
+  const agents = roster.agents.map((agent) => {
+    const raw: Record<string, unknown> = {
+      name: agent.name,
+      runtime: agent.runtime,
+      class: agent.className,
+    };
+    if (agent.workingDirectory !== undefined) {
+      raw['working_directory'] = agent.workingDirectory;
+    }
+    if (agent.modelHint !== undefined) {
+      raw['model_hint'] = agent.modelHint;
+    }
+    if (agent.persistentPersona !== undefined) {
+      raw['persistent_persona'] = agent.persistentPersona;
+    }
+    if (agent.resetBetweenTasks !== undefined) {
+      raw['reset_between_tasks'] = agent.resetBetweenTasks;
+    }
+    if (agent.kickstartTemplate !== undefined) {
+      raw['kickstart_template'] = agent.kickstartTemplate;
+    }
+    return raw;
+  });
+
+  const runtimes: Record<string, { reset_command: string }> = {};
+  for (const [runtime, config] of Object.entries(roster.runtimes)) {
+    runtimes[runtime] = { reset_command: config.resetCommand };
+  }
+
+  const raw: Record<string, unknown> = {
+    version: roster.version,
+    transport: roster.transport,
+    tmux: {
+      socket_name: roster.tmux.socketName,
+      holder_session: roster.tmux.holderSession,
+    },
+    defaults: {
+      working_directory: roster.defaults.workingDirectory,
+    },
+    runtimes,
+    agents,
+  };
+
+  return YAML.stringify(raw);
+}
+
 /**
  * Prompt interactively for a fleet profile via stdin readline.
  * AI-free: no LLM calls — pure readline menu.

packages/mosaic/src/commands/launch.ts

@@ -291,12 +291,23 @@ function buildPrdBlock(): string {
 
 // ─── Runtime prompt builder ──────────────────────────────────────────────────
 
-function buildRuntimePrompt(runtime: RuntimeName): string {
+/**
+ * Compose the full runtime contract for a harness: the resident-by-value core
+ * (CONSTITUTION + AGENTS + USER + TOOLS + runtime) plus operator overlays
+ * (`*.local.md` deltas), merged in precedence order so the model gets one
+ * pre-merged blob (DESIGN §3.2 / R7). Overlays are injected as deltas by value;
+ * base files keep their existing residency (USER injected; SOUL/STANDARDS are
+ * load-on-demand, so only their small `.local` deltas are injected here).
+ *
+ * `mosaicHome` is parameterized for testability; production callers use the
+ * module-level default.
+ */
+export function composeContract(runtime: RuntimeName, mosaicHome: string = MOSAIC_HOME): string {
   const runtimeContractPaths: Record<RuntimeName, string> = {
-    claude: join(MOSAIC_HOME, 'runtime', 'claude', 'RUNTIME.md'),
+    claude: join(mosaicHome, 'runtime', 'claude', 'RUNTIME.md'),
-    codex: join(MOSAIC_HOME, 'runtime', 'codex', 'RUNTIME.md'),
+    codex: join(mosaicHome, 'runtime', 'codex', 'RUNTIME.md'),
-    opencode: join(MOSAIC_HOME, 'runtime', 'opencode', 'RUNTIME.md'),
+    opencode: join(mosaicHome, 'runtime', 'opencode', 'RUNTIME.md'),
-    pi: join(MOSAIC_HOME, 'runtime', 'pi', 'RUNTIME.md'),
+    pi: join(mosaicHome, 'runtime', 'pi', 'RUNTIME.md'),
   };
 
   const runtimeFile = runtimeContractPaths[runtime];
@@ -331,27 +342,55 @@ For required push/merge/issue-close/release actions, execute without routine con
 `);
 
   // CONSTITUTION.md (L0 — the non-negotiable law; lead with it). Tolerant of
-  // pre-constitution installs that have not been re-seeded yet.
+  // pre-constitution installs that have not been re-seeded yet. Injected by
-  const constitution = readOptional(join(MOSAIC_HOME, 'CONSTITUTION.md'));
+  // value verbatim so the bare-launch fallback read is byte-equal (R8).
+  const constitution = readOptional(join(mosaicHome, 'CONSTITUTION.md'));
   if (constitution) parts.push(constitution);
 
   // AGENTS.md
-  parts.push(readFileSync(join(MOSAIC_HOME, 'AGENTS.md'), 'utf-8'));
+  parts.push(readFileSync(join(mosaicHome, 'AGENTS.md'), 'utf-8'));
 
-  // USER.md
+  // USER.md (+ USER.local.md operator overlay, appended directly under the
-  const user = readOptional(join(MOSAIC_HOME, 'USER.md'));
+  // profile its base owns).
+  const user = readOptional(join(mosaicHome, 'USER.md'));
   if (user) parts.push('\n\n# User Profile\n\n' + user);
+  const userLocal = readOptional(join(mosaicHome, 'USER.local.md'));
+  if (userLocal.trim()) {
+    parts.push('\n\n## Operator Overlay (USER.local.md)\n\n' + userLocal);
+  }
 
   // TOOLS.md
-  const tools = readOptional(join(MOSAIC_HOME, 'TOOLS.md'));
+  const tools = readOptional(join(mosaicHome, 'TOOLS.md'));
   if (tools) parts.push('\n\n# Machine Tools\n\n' + tools);
 
+  // Operator overlays whose base layers are load-on-demand (SOUL, STANDARDS):
+  // inject only the small `.local` delta by value so the customization reaches
+  // the model without re-injecting the full base prose (preserves the byte
+  // budget). Absent `.local` files → base-only, automatically (R7 §3.2).
+  const overlayBlocks: string[] = [];
+  const soulLocal = readOptional(join(mosaicHome, 'SOUL.local.md'));
+  if (soulLocal.trim()) {
+    overlayBlocks.push('## Persona Overlay (SOUL.local.md)\n\n' + soulLocal.trim());
+  }
+  const standardsLocal = readOptional(join(mosaicHome, 'STANDARDS.local.md'));
+  if (standardsLocal.trim()) {
+    overlayBlocks.push('## Standards Overlay (STANDARDS.local.md)\n\n' + standardsLocal.trim());
+  }
+  if (overlayBlocks.length > 0) {
+    parts.push('\n\n# Operator Overlays\n\n' + overlayBlocks.join('\n\n'));
+  }
+
   // Runtime-specific contract
   parts.push('\n\n# Runtime-Specific Contract\n\n' + readFileSync(runtimeFile, 'utf-8'));
 
   return parts.join('\n');
 }
 
+/** @deprecated internal alias — use composeContract. Retained for call-site clarity. */
+function buildRuntimePrompt(runtime: RuntimeName): string {
+  return composeContract(runtime);
+}
+
 // ─── Session lock ────────────────────────────────────────────────────────────
 
 function writeSessionLock(runtime: string): void {
@@ -976,6 +1015,22 @@ export function registerLaunchCommands(program: Command): void {
     launchRuntime(runtime, extraArgs, yolo);
   });
 
+  // compose-contract — emit the composed runtime contract (base + operator
+  // overlays) for a harness to stdout, without launching. For inspection,
+  // `mosaic doctor`, diffing, and the composer test (R7).
+  program
+    .command('compose-contract <harness>')
+    .description('Print the composed runtime contract (base + *.local overlays) for a harness')
+    .action((harness: string) => {
+      const valid: RuntimeName[] = ['claude', 'codex', 'opencode', 'pi'];
+      if (!valid.includes(harness as RuntimeName)) {
+        console.error(`Unknown harness '${harness}'. Expected one of: ${valid.join(', ')}.`);
+        process.exitCode = 64;
+        return;
+      }
+      process.stdout.write(composeContract(harness as RuntimeName));
+    });
+
   // Coord (mission orchestrator)
   program
     .command('coord')

packages/mosaic/src/runtime/update-checker.reseed.spec.ts

@@ -0,0 +1,85 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import {
+  buildReseedCommand,
+  buildRelaunchCommands,
+  readRosterAgentNames,
+  runFrameworkReseed,
+} from './update-checker.js';
+
+/**
+ * F3-m3 / R13: `mosaic update` re-seeds the framework + (opt-in) relaunches
+ * durable agents so shipped launcher/runtime changes activate. These cover the
+ * pure builders + the missing-installer guard (the exec path is integration).
+ */
+
+describe('buildReseedCommand', () => {
+  it('invokes the package install.sh in data-safe sync-only keep mode', () => {
+    const out = buildReseedCommand('/pkg/framework', '/home/u/.config/mosaic');
+    expect(out.installer).toBe('/pkg/framework/install.sh');
+    expect(out.command).toBe('bash /pkg/framework/install.sh');
+    expect(out.env).toEqual({
+      MOSAIC_SYNC_ONLY: '1',
+      MOSAIC_INSTALL_MODE: 'keep',
+      MOSAIC_HOME: '/home/u/.config/mosaic',
+    });
+  });
+});
+
+describe('buildRelaunchCommands', () => {
+  it('builds a systemctl --user restart per agent unit', () => {
+    expect(buildRelaunchCommands(['orchestrator', 'coder0'])).toEqual([
+      ['systemctl', '--user', 'restart', 'mosaic-agent@orchestrator.service'],
+      ['systemctl', '--user', 'restart', 'mosaic-agent@coder0.service'],
+    ]);
+  });
+
+  it('is empty for an empty roster', () => {
+    expect(buildRelaunchCommands([])).toEqual([]);
+  });
+});
+
+describe('readRosterAgentNames', () => {
+  let home: string;
+
+  beforeEach(() => {
+    home = mkdtempSync(join(tmpdir(), 'mosaic-roster-'));
+  });
+  afterEach(() => {
+    rmSync(home, { recursive: true, force: true });
+  });
+
+  it('returns [] when no roster exists', () => {
+    expect(readRosterAgentNames(home)).toEqual([]);
+  });
+
+  it('extracts agent names from roster.yaml', () => {
+    mkdirSync(join(home, 'fleet'), { recursive: true });
+    writeFileSync(
+      join(home, 'fleet', 'roster.yaml'),
+      [
+        'version: 1',
+        'agents:',
+        '  - name: orchestrator',
+        '    runtime: pi',
+        '  - name: coder0',
+        '    runtime: claude',
+        '  - name: "reviewer-1"',
+        '    runtime: codex',
+      ].join('\n') + '\n',
+    );
+    expect(readRosterAgentNames(home)).toEqual(['orchestrator', 'coder0', 'reviewer-1']);
+  });
+});
+
+describe('runFrameworkReseed', () => {
+  it('reports not-ok (not throw) when the installer is absent', () => {
+    const missing = mkdtempSync(join(tmpdir(), 'mosaic-noinstaller-'));
+    const res = runFrameworkReseed(missing, join(missing, 'home'));
+    expect(res.ok).toBe(false);
+    expect(res.reason).toContain('installer not found');
+    rmSync(missing, { recursive: true, force: true });
+  });
+});

packages/mosaic/src/runtime/update-checker.ts

@@ -16,7 +16,8 @@
 import { execSync } from 'node:child_process';
 import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs';
 import { homedir } from 'node:os';
-import { join } from 'node:path';
+import { dirname, join, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
 
 // ─── Types ──────────────────────────────────────────────────────────────────
 
@@ -453,6 +454,98 @@ export function getInstallAllCommand(outdated: PackageUpdateResult[]): string {
   return `npm i -g ${pkgs.join(' ')}`;
 }
 
+// ─── Post-update framework re-seed + agent relaunch (F3-m3 / R13) ─────────────
+//
+// `mosaic update` installs the new npm CLI but, on its own, leaves the framework
+// files in ~/.config/mosaic/ stale — so shipped launcher/runtime changes (e.g.
+// the agent-name export + native heartbeat) never ACTIVATE until a re-seed.
+// These helpers run the package's own install.sh in sync-only mode (the P4
+// data-safe reconcile: framework-owned overwrite + backup-once; SOUL/USER/
+// *.local/credentials preserved) and, opt-in, relaunch durable agents.
+
+/** Resolve the framework/ directory bundled in the installed package. */
+export function resolveBundledFrameworkRoot(): string {
+  // dist/runtime/update-checker.js → ../../framework (package files: dist + framework)
+  return resolve(dirname(fileURLToPath(import.meta.url)), '..', '..', 'framework');
+}
+
+export const FRAMEWORK_RESEED_PACKAGE = PKG;
+
+/**
+ * Build the framework re-seed invocation: the package's install.sh in
+ * sync-only mode (file phase only — no environment-touching post-install),
+ * keep mode (never overwrite user files). Returned as data so it is unit
+ * testable; `runFrameworkReseed` executes it.
+ */
+export function buildReseedCommand(
+  frameworkRoot: string,
+  mosaicHome: string,
+): { installer: string; command: string; env: Record<string, string> } {
+  const installer = join(frameworkRoot, 'install.sh');
+  return {
+    installer,
+    command: `bash ${installer}`,
+    env: {
+      MOSAIC_SYNC_ONLY: '1',
+      MOSAIC_INSTALL_MODE: 'keep',
+      MOSAIC_HOME: mosaicHome,
+    },
+  };
+}
+
+/**
+ * Re-seed the framework from the freshly-installed package. Returns a result
+ * describing what happened (so callers can message + decide on relaunch).
+ * Best-effort: a missing installer or a non-zero exit is reported, not thrown.
+ */
+export function runFrameworkReseed(
+  frameworkRoot = resolveBundledFrameworkRoot(),
+  mosaicHome = join(homedir(), '.config', 'mosaic'),
+): { ok: boolean; reason?: string } {
+  const { installer, command, env } = buildReseedCommand(frameworkRoot, mosaicHome);
+  if (!existsSync(installer)) {
+    return { ok: false, reason: `installer not found: ${installer}` };
+  }
+  try {
+    execSync(command, { stdio: 'inherit', env: { ...process.env, ...env }, timeout: 120_000 });
+    return { ok: true };
+  } catch (err) {
+    return { ok: false, reason: err instanceof Error ? err.message : String(err) };
+  }
+}
+
+/**
+ * Best-effort parse of the fleet roster for agent names (used to relaunch
+ * durable agents after a re-seed). Returns [] when no roster exists.
+ */
+export function readRosterAgentNames(mosaicHome = join(homedir(), '.config', 'mosaic')): string[] {
+  const rosterPath = join(mosaicHome, 'fleet', 'roster.yaml');
+  if (!existsSync(rosterPath)) return [];
+  let text: string;
+  try {
+    text = readFileSync(rosterPath, 'utf-8');
+  } catch {
+    return [];
+  }
+  // Roster agents are listed as `- name: <id>` entries under `agents:`.
+  const names: string[] = [];
+  for (const line of text.split('\n')) {
+    const m = line.match(/^\s*-?\s*name:\s*["']?([A-Za-z0-9._-]+)["']?\s*$/);
+    if (m && m[1]) names.push(m[1]);
+  }
+  return names;
+}
+
+/** Build the per-agent systemd relaunch commands (drain+relaunch via restart). */
+export function buildRelaunchCommands(agentNames: string[]): string[][] {
+  return agentNames.map((name) => [
+    'systemctl',
+    '--user',
+    'restart',
+    `mosaic-agent@${name}.service`,
+  ]);
+}
+
 /**
  * Format a table showing all packages with their current/latest versions.
  */