---
name: ca-review
description: Review a diff with the reviewer fleet, funneled to one triaged verdict. Targets the current working diff, a path, or an inbound GitHub PR.
argument-hint: "[path | #<pr> | <pr-url>] (defaults to the current diff)"
---

# $ca-review — diff review

Read-only review of a change. Routes to `dispatching-parallel-agents` ([routines/dispatching-parallel-agents/SKILL.md](../../routines/dispatching-parallel-agents/SKILL.md)): dispatches the reviewer fleet by path matrix, dedupes, then funnels through `finding-triage` → `verdict-aggregator` to a single in-memory verdict. No code is modified.

**The change under review does not have to be yours.** `$ca-review #123` reviews an inbound pull request through the same fleet, the same matrix, and the same triage. That is the point of issue #80: a tool that only reviews the diff you just wrote is a linter for authors, not a gate for a team, and reviewing code you did NOT write is where a governance gate earns its keep.

It is an ARGUMENT, not a second command. The scope resolver already took one, the fleet is scope-agnostic, and every phase downstream operates on a diff regardless of where it came from — so a `$ca-review-pr` would be a whole public surface (catalog, three host projections, README counts, sidebar) whose only distinguishing feature is where the diff was fetched from.

## Flow

1. Resolve scope from `$ARGUMENTS`:
   - **empty** → the current working diff (unchanged default).
   - **a path** → that path (unchanged).
   - **`#<number>`, a bare number, or a GitHub PR URL** → an INBOUND PR. Fetch its diff with
     `gh pr diff <number>` and review that. If `gh` is missing or unauthenticated, STOP and say so —
     do NOT silently fall back to the working diff, which would report a verdict on the wrong change
     under the PR's name.

   For a PR target, resolve the diff ONCE and review that text. Do not re-fetch per reviewer: the
   fleet runs in parallel, and a PR updated mid-review would otherwise have different reviewers
   reading different code and a triage that reconciles findings from two versions.
2. Build the unit list by path matrix; each matched reviewer is one read-only unit:

   | Reviewer | Dispatched when scope touches |
   |---|---|
   | `security-reviewer` | auth, middleware, secrets, deploy/CI, any security-sensitive path |
   | `auth-crypto-reviewer` | authn, crypto, key handling, secrets |
   | `dependency-reviewer` | `package.json`, lockfiles, base images, dependency manifests |
   | `migration-reviewer` | DB migration file add/modify |
   | `coverage-auditor` | any source change (test coverage vs. obligations) |
   | `architecture-drift-reviewer` | code that may diverge from accepted ADRs in `.codearbiter/decisions/` |

3. Route to `dispatching-parallel-agents` with that unit list (read-only batch — no collision check).
   It dedupes overlapping findings, then funnels through `finding-triage` (severity + inline
   `[NEEDS-TRIAGE]` on out-of-scope items) → `verdict-aggregator` (single read-only verdict).
4. Surface the aggregated verdict: findings by severity, file:line, remediation, and the applicable
   control from `<project-root>/.codearbiter/security-controls.md` for security findings.
5. **For a PR target, posting the verdict is a separate, confirmed step.** Report locally first; post only on explicit instruction, with `gh pr review <number> --comment --body-file <file>`. A review comment on someone else's PR is outward-facing and effectively public the moment it lands — it notifies subscribers and cannot be un-sent. Never `--request-changes` or `--approve` from here: those carry merge authority, and this command produces a finding list, not a maintainer's decision.

## Severity

- **CRITICAL** — exploitable vuln, secret exposure, banned primitive, data-integrity breach.
- **HIGH** — significant compliance gap or unsafe pattern.
- **MEDIUM** — standards deviation or coverage gap.
- **LOW** — informational or style.

## Hard gate

Read-only — MUST NOT modify a file, and MUST NOT check out, merge, or otherwise move the repository to the PR's branch: reviewing an inbound PR means reading its DIFF, not adopting its code, and a checkout would run its content through hooks that trust the working tree. BLOCK on any CRITICAL or HIGH finding on your OWN change: it must be resolved before `$ca-pr`. On an inbound PR there is nothing local to block — the verdict is the deliverable. MUST NOT consume raw reviewer output — only the `finding-triage` → `verdict-aggregator` verdict. MUST NOT resolve a `[CONFIRM-NN]` surfaced during review by guessing.

## When NOT to use

- Opening a PR (reviews dispatch automatically) → `$ca-pr`.
- A periodic full-codebase sweep → `$ca-checkpoint`.
- A pre-implementation threat model → `$ca-threat-model`.
- A question about the code → `$ca-btw`.