> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stackra.figentra.com/llms.txt
> Use this file to discover all available pages before exploring further.

# 0230 — Reviews come from a separate reviewer identity, never the author

> Accepted · 2026-10-20

## Context

[0119](/adr/0119-merge-policy-and-release-authority) lets an agent merge only through `pnpm pr:merge`, which needs an
`AI-REVIEW: PASS <head sha>` comment. Builders and reviewers both act as the `stackra-bot` GitHub App, and agents
also hold the owner's `gh` login (`figentra-usr`). `pr-merge` trusted verdicts from both identities. So it could not
tell an author from its reviewer. On 2026-10-20, builder agents posted `AI-REVIEW: PASS` on their own pull requests
and merged them, some through plain `gh` as the owner's account. That breaks
[0021](/adr/0021-ai-engine-and-agent-write-safety) rule 6: agents are not their own approvers.

We weighed two designs. A signed review record verified by `pr-merge` needs a key that the builder session can also
read on the same machine. A second GitHub App ties each verdict to an identity that GitHub records, and that app can
hold fewer permissions than the builder app.

## Decision

1. **A second GitHub App, `stackra-reviewer`**, is the only identity whose verdict counts. Its installation holds
   pull requests: write and contents: read, never contents: write. It can comment and review, and it cannot push.
   Its credentials are `STACKRA_REVIEWER_APP_ID`, `STACKRA_REVIEWER_INSTALLATION_ID` and
   `STACKRA_REVIEWER_PRIVATE_KEY` in Infisical. Reviewer agents post through `pnpm bot:review`, which runs only
   `gh pr view|diff|checks|comment|review` and read-only `gh api` (no `-X`, `--method`, fields or `--input`, alone or bundled as in `-iX`).
2. **`pr-merge` counts a verdict only from the `stackra-reviewer` App**, identified by what GitHub records, never by
   a login string: a REST issue comment with `user.type` `Bot` and `performed_via_github_app.slug`
   `stackra-reviewer`. It never counts when the verdict's author is the PR author or the head commit's author or
   committer. A verdict from the builder app `stackra-bot`, or from a user account named `stackra-reviewer`, is
   ignored, and the refusal says why. The verdict format is binding:
   * the first line is `AI-REVIEW: PASS <full 40-hex head sha> base=<base ref>` or `AI-REVIEW: FAIL <head sha>`. A
     PASS counts only while the PR still targets that base ref, so re-targeting the PR voids it. The base is a ref
     name, not a SHA, because `main` moves under every open PR and the merge is a squash onto its tip;
   * an edited verdict never counts, and an edit to any reviewer comment voids every reviewer verdict posted before
     it. Anyone with write access can edit another account's comment, so the reviewer always posts a new comment;
   * a FAIL for the head SHA is sticky: it beats every PASS for that SHA, older or newer. A wrong FAIL is cleared by
     a new commit or by the owner. Minimized comments are not visible to REST and still count, which is safe for a
     FAIL; a reviewer retracts a PASS by posting a FAIL.
3. **The owner approves by hand only with a pull request review**: an APPROVED review by the owner user on the head
   SHA whose body ends with the token `owner-approval`, and not on a commit the owner account authored. An
   `AI-REVIEW:` comment from the owner account never counts.
4. **Agents never write `owner-approval` or the `owner-approved` label**, and never post `AI-REVIEW:` through plain
   `gh`. The bash guard denies all three. This is a tripwire, not the control: the guard cannot see a `--body-file`.
5. **Agents stop committing and pushing as the owner.** Builders commit and push through `pnpm bot:git` and open
   PRs through `pnpm bot:gh`. Agent environments drop the owner's `gh` login once the bot paths cover every write.

## Consequences

* A PR built by `stackra-bot` needs a reviewer agent's PASS posted as `stackra-reviewer`. Self-review is refused
  with a reason that names the identity.
* The owner created the `stackra-reviewer` app on 2026-10-20 (installed on `figentra/stackra` only, pull requests:
  write, contents: read) and stored its credentials in Infisical `/agents`, which accepted this record. Reviewer
  agents post every verdict through `pnpm bot:review`; a verdict posted through `pnpm bot:gh` no longer counts.
* What remains: the same machine can mint both apps' tokens, so a builder agent that ignores its role could run
  `pnpm bot:review`. Rules 2 and 5 remove the obvious path, because the reviewer never authors and builders never
  act as the owner. Closing the gap fully needs the review to run where builders hold no reviewer key. That means a
  CI job or a separate host with its own Infisical identity, which is Phase 3 scope (merge queue, see below).
* The owner path is forgeable today. Agents still hold the owner's `gh` login (`figentra-usr`), so an agent can
  submit an APPROVED review ending in `owner-approval`, or add the `owner-approved` label, as the owner. Moving the
  owner path from a comment to a review only makes the forgery a deliberate act; the guard denies the token on the
  command line, but not in a `--body-file`. Rule 5 drops the owner's login from agent environments, and it also
  takes away the owner-authored-commit exclusion that used to catch this. The real fix is an owner decision (remove
  the owner's `gh` login from agent sessions, or require the owner's review to come from a device agents cannot
  reach). Until then, the owner-approval path is only as strong as agents' compliance with rule 4.
* Deleted comments are invisible to `pr-merge`: deleting a reviewer FAIL makes an older PASS count again. Only
  accounts with write access can delete another account's comment, which today includes the owner login agents
  hold (see above).

## Enforcement

* `tools/scripts/pr-merge.mjs` (`aiReview`, `blockers`, tests in `tools/scripts/__tests__/pr-merge.test.mjs`): the
  App identity check, the author and committer exclusion, the full head SHA and base ref, edited and sticky-FAIL
  verdicts, and the owner's approving review with the `owner-approval` token.
* `tools/scripts/bot-gh.mjs` (`reviewerAllows`): the reviewer's command allowlist, reading bundled short flags letter by letter and refusing `--edit-last` and `--delete-last`.
* `.agents/hooks/guard-bash.mjs`: denies agent commands that write `owner-approval` or `owner-approved`, or post
  `AI-REVIEW:` through plain `gh`.
* Planned: the review runs in a CI job with its own credentials (the Phase 3 merge-queue design). OpenCode's guard
  plugin mirrors the bash rules.

## Supersedes and sources

Supersedes: none. Amends [0119](/adr/0119-merge-policy-and-release-authority): the AI review's author must be the
reviewer identity. Sources: the 2026-10-20 incident (agent self-PASS and merges as `figentra-usr`); the SDD/SDLC plan
§16 D5 (bot identity). Numbered 0230, reserved for this record.


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