The discipline (ADR-0003, the promote flow, the operating rules) was written
down and still depended on whoever was driving choosing to follow it. On
2026-07-25 an agent session wrote five documents into the production ledger
through direct API calls, bypassing the promote flow entirely — a correct result
reached by a path nobody could audit. A rule an operator can skip is a
recommendation.
The five stages are now chained by artefacts on disk. Each refuses to run until
the previous produced its file, and the file says what it needs to hear:
rehearse (sandbox, host-guarded) -> judge --pre -> gate (human) -> apply
(prod) -> judge --post. The gate binds to a manifest digest, so approving a
change-set approves THAT change-set.
An op is defined ONCE, as an API call, and replayed on the sandbox then on
production — because the first design described each write twice (a sandbox
script input and a prod API body) and the pre-gate judge immediately caught them
diverging: the rehearsal was creating a EUR invoice with no due date while
production would have received a USD one at 60 days. Two descriptions of the
same write are two things that can disagree.
Judges are context-free, cross-family per the PRD qa-strategy rule, and
advisory: a BLOCK still lets the operator approve, and the override is recorded
with their name. Blocking authority stays with the human gate and the host
guards — an LLM verdict never silently starts or stops a production write.
Verified end to end against the real 24/08 change-set (M3 deferred, USD 3,000):
- pre-gate judge (Mistral) returned BLOCK twice, correctly — first on the
sandbox/prod divergence, then on a duplicate left by a repeated rehearsal;
- apply refuses after a rejected gate;
- apply refuses without ARCO_PROD_CONFIRM;
- editing an amount after approval invalidates the gate on digest mismatch.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01VRShc4QhLLU73FLHx9vskh
