greenfield(fomo-lin): session 2 — init + first bare seat; findings F6-F10

install → init → launch broken at four consecutive links on fresh main:
F6 eval injection in mosaic-init (SECURITY), F7 init drops installer's
mcpServers block, F8 missing fleet roster = raw stack trace, F9 activation
probe 2.0s timeout < 2.6s CLI cold-start on modest hardware (flagship),
F10 shipped lease-broker unit never installed. Seat launched after
documented workarounds; runtime-contract injection verified in-seat.

Co-Authored-By: Claude Fable 5 <[email protected]>

docs/reports/greenfield/fomo-lin.md

@@ -80,7 +80,73 @@ installer's bundle and the repo dir — have diverged.
   laptop has no ssh keys. ssh reach would need Jason (key provisioning + route/VPN).
 - Gitea write to the stack repo: verified by the push of this very branch (token `usc_mos`).
 
+## Session 2 (2026-08-08 later) — `mosaic init` + first bare seat
+
+`mosaic init` completed (SOUL.md / USER.md / TOOLS.md generated; TOOLS.md was backed up
+before overwrite — the contrast with F2 shows the codebase already knows how). Its
+runtime-adapter step correctly REFUSED to wire mutator-gate/receipt-observer hooks
+(activation half absent, #869) — loud, explained, fail-safe. Good.
+
+First bare seat: **launched** — `mosaic claude --model sonnet` → Claude Code v2.1.226,
+runtime-contract injection verified from inside the seat. But it took findings F6–F10 to
+get there; on an untouched fresh main install, install → init → launch is broken at
+FOUR consecutive links.
+
+### F6 — SECURITY: `mosaic-init` eval-injects free-text answers
+
+`tools/_scripts/mosaic-init` line 142: `eval "$var_name=\"$value\""`. Any answer
+containing `"` crashes init mid-flow (reproduced: exit 127, USER.md never written);
+an answer containing `$( )` would EXECUTE arbitrary commands. Fix: `printf -v`.
+Same bug in the NON_INTERACTIVE default branch. Related: init exits 1 even on success
+when enforcement wiring is (correctly) refused — poisons any scripted chaining.
+
+### F7 — init silently drops the installer's `mcpServers` block → launcher refuses to run
+
+init's "Updating runtime adapters" rewrote `~/.claude/settings.json` and removed the
+`mcpServers.sequential-thinking` block the installer had written 11 min earlier.
+`mosaic claude` hard-requires that MCP → launch refused. The prescribed fix command
+(`mosaic-ensure-sequential-thinking --runtime claude`) works. So the happy path is
+install → init → BROKEN → hand-run a repair script. Merge-not-replace (F2) fixes this too.
+
+### F8 — no fleet roster on a fresh install; launcher dies with a raw stack trace
+
+`mosaic claude` throws an uncaught `Error: Fleet communications contract unavailable: no
+fleet roster at ~/.config/mosaic/fleet/roster.{yaml,json}` (full Node stack trace to the
+user). Nothing in install or init creates a roster (wizard untested here — `--no-auto-launch`;
+if the wizard seeds one, the bare-flow gap still stands). Unblocked by hand-authoring a
+minimal site roster from `fleet/examples/minimal.yaml`.
+
+### F9 — FLAGSHIP: activation-probe timeout loses to CLI cold-start on modest hardware
+
+`activation_version_gate.py` gives the `mosaic __lease-capability` probe
+`PROBE_TIMEOUT_SECONDS = 2.0`. On fomo-lin the CLI answers CORRECTLY in **~2.55–2.61s
+every run** (Node startup cost). Timeout → fail-closed → every bare `mosaic claude`
+launch aborts (exit 65) with an error blaming "mosaic not on PATH … framework/CLI version
+skew" — neither true. Invisible on fast dev boxes; fatal on laptops. Suggest: raise/make
+configurable the timeout, warm-probe cache, and split the three failure causes into
+distinct messages. Local workaround (documented, removable):
+`MOSAIC_LEASE_VERSION_PROBE_COMMAND` pointed at a script emitting the verified payload
+instantly (`~/.local/bin/mosaic-lease-probe-fast`).
+
+### F10 — shipped lease-broker unit is never installed → registration denied
+
+With F9 bypassed, launch dies with "Mosaic lease broker registration failed; runtime
+launch denied": the broker daemon isn't running, and although the framework SHIPS
+`systemd/user/mosaic-lease-broker.service`, nothing installs/enables it.
+`systemctl --user link` + `enable --now` of the shipped unit → READY instantly, launch
+proceeds. Installer/init/wizard should own this step.
+
+### Observations (not filed as findings)
+
+- Launcher settings audit demands `mutator-gate.py` while init refuses to wire it —
+  main's components disagree about the gated state (fold into #1113/F4).
+- Seat context: runtime contract injected ✓; SOUL.md NOT injected (seat confirmed) —
+  matches AGENTS.md read-on-demand load order, but README says the launcher "checks for
+  SOUL.md". Question for lead, not a finding.
+- `--ref next` install path verified available (flag exists, next archive HTTP 200) — not
+  exercised; fomo-lin stays main-as-shipped per lead ruling.
+
 ## Next
 
-- `mosaic init` (SOUL.md) + first seat launch via `mosaic claude` → milestone comms to fred.
+- Milestone comms sent at: install complete ✓ / first seat launched ✓.
 - First gated-seat probe deliberately deferred until PR #1109 lands (known deny-only state).