The enforcement half of the lease broker ships and denies; the promotion half
has no production caller anywhere in the package. Verified across 0.0.48, 0.0.49
and 0.0.50-next.2207: begin_verification / observe_receipt / promote_lease are
invoked only by broker-test-client.ts, the acceptance spec, unit tests, and two
probes under docs/.
Consequence: no lease on any host can reach VERIFIED, so mutator-gate denies
every mutator with MUTATOR_UNVERIFIED via a gate that nothing shipped can
satisfy. Runtimes that enforce the gate in-process (pi, via mosaic-extension's
tool_call hook) are bricked for mutators; runtimes whose gate is wired through a
settings hook escape only when that hook is absent — i.e. by being ungated.
This adds the client. It implements protocol steps 1, 4 and 5:
1. begin_verification -> mint a challenge, return the exact receipt text
2. the MODEL emits that text verbatim as its entire latest message
3. the runtime adapter ships that message to the observer socket
4. observe_receipt -> PENDING_PROMOTION
5. promote_lease -> VERIFIED
Step 2 is deliberately NOT implemented here, and that is the point.
is_verbatim_receipt uses hmac.compare_digest against the exact minted string —
explicitly "not a transcript substring" — which makes promotion a LIVENESS
PROOF: it requires a live model that received the challenge in its context and
echoed it exactly.
receipt-observer-client.py will post ANY string as the latest assistant message.
A promotion client that posted its own receipt would satisfy the broker while
proving nothing — a gate-disabler indistinguishable from a working fix unless
someone specifically looks. Emitting the receipt therefore belongs to the runtime
adapter, where a real model turn happens. A local diagnostic that posts its own
receipt exists in the operator's repo and is deliberately NOT shipped here.
The construction binds the exact normative source bytes, so a VERIFIED lease
means "this agent is running THIS law", not merely "this session id is known".
h_source/h_payload are derived by importing the framework's own
normative_fragments.build_payload rather than reimplementing it: the broker
derives them the same way and any divergence yields PAYLOAD_BINDING_MISMATCH.
There must be exactly one implementation.
session_identity() prefers the generation FILE over the env var, matching
lease_generation.py. Sending a generation higher than the broker's would revoke
the session's own authority (daemon.py:342-344), so it never guesses.
Verified end-to-end on sb-it-1-dt under a real lease-gated anchor: a mutator
denied rc=2 MUTATOR_UNVERIFIED, then begin -> observe -> promote -> VERIFIED,
then the same mutator allowed rc=0. Negative controls pass: a fresh session is
still denied, and an unrelated session still reads UNVERIFIED — promotion is
per-session and does not leak.
Still open: adapter wiring for step 2. Lazy promotion on first mutator attempt
avoids colliding with the Constitution's first-response mode declaration, since
compare_digest requires the receipt to be the WHOLE message.
Mosaic wrote into the operator's harness base installs — ~/.claude,
~/.pi/agent, ~/.codex, ~/.config/opencode — for settings, instructions, and a
102-symlink skill farm per harness. Any experiment with hooks or gating
therefore mutated the operator's own tooling, and a broken framework change
could take out the very harness needed to repair it.
Harness home isolation
----------------------
Each runtime now reads config from a dedicated mosaic-owned home via the
harness's own config-dir variable:
claude CLAUDE_CONFIG_DIR ~/.config/mosaic/.claude
pi PI_CODING_AGENT_DIR ~/.config/mosaic/.pi (replaces ~/.pi/agent)
codex CODEX_HOME ~/.config/mosaic/.codex
opencode XDG_CONFIG_HOME ~/.config/mosaic/.opencode
These paths are manifest-UNKNOWN, so rule 3 (#791) resolves them to operator
ownership and a keep-mode upgrade can neither overwrite nor prune them.
A bare `claude` / `pi` keeps its own config AND auth, making it a structural
break-glass rather than one depending on restoring a file under pressure.
opencode is blunter than the rest: it has no dedicated variable and follows XDG,
so isolation also relocates XDG lookups for anything it spawns. Documented in
place.
mosaic-sync-skills now links into those homes and cleans the legacy farms it
previously planted in base installs. Ownership is proven by RESOLUTION, not by
name — only symlinks resolving inside the canonical/local skills dirs are
removed, mirroring the refusal already in commands/skill.js. Verified against a
real install: codex's own .system directory survived while its 102 mosaic links
were removed. Both resolution prefixes are length-checked first; an empty prefix
would make "$resolved" == "$prefix/"* match every absolute path and delete
foreign symlinks.
Immutable launch record
-----------------------
Every launch now appends one record to fleet/run/sessions/events.ndjson before
exec. Mandatory, mechanical, no model involvement.
pi rewrites its own argv to a bare `pi`, so /proc/<pid>/cmdline destroys the
launch evidence — that has already produced a confident wrong diagnosis ("this
agent bypassed the launcher"), disproved only by the parent's argv and only
because the parent had not yet exited. A record written before exec is the only
place this survives.
The path is the #797 Runtime Session Ledger, already operator-classified and
already covered by test-upgrade-manifest-guard.sh, which seeds it and proves a
populated ledger survives keep-mode upgrades — but nothing shipped ever wrote
it. This implements it in the shape that guard already asserts (0600 files under
a 0700 dir).
`mosaic` writes session.launch; launch-runtime.py appends lease.register with
the broker session id and activation capability. They correlate by an explicit
MOSAIC_LAUNCH_ID, never by pid: execRuntime uses spawnSync, so the runtime is a
child with a different pid.
Records normative fragment digests (CONSTITUTION/AGENTS/SOUL/USER/STANDARDS/
TOOLS/RUNTIME) — the same set the broker hashes for promotion, so drift is
mechanically detectable rather than a matter of judgement.
Credential-safe: env is captured as PRESENT NAMES ONLY, and argv values over
256 bytes become a sha256 + length rather than being inlined.
Also fixes CLI_VERSION resolution: '@mosaicstack/mosaic/package.json' is not in
the package exports map and always throws ERR_PACKAGE_PATH_NOT_EXPORTED.
resolveTool() uses that same failing specifier, which is why its documented
preference for bundled tools over the deployed ~/.config/mosaic copy has never
once applied — noted in place, not fixed here.
Verified on sb-it-1-dt: isolated homes written and base installs byte-identical
for all four harnesses; 408 legacy symlinks removed with 1 foreign entry
preserved; launch records paired across the spawn boundary. typecheck shows zero
errors in launch.ts (the @mosaicstack/types failures are pre-existing and
reproduce on a pristine origin/main worktree).
Part of #869
Mos (id-11) Gate-16 merge: independent APPROVE @75235ef8 (9/9, no live host mutation), author id2 != approver id11, CI green wp1971.
Co-authored-by: jason.woltje <[email protected]>
Co-committed-by: jason.woltje <[email protected]>
Jason Woltje
jason.woltjeandMos