code-review

# Code Review — Multi-Agent PR Review User-invokable orchestrator for code-PR review across any repo: Copilot for line-level findings, parallel subagents for the architectural and operational misses line-level review can't see. (Validation evidence and origin story: [README](README.md).) **Fallbacks:** no `gh` or not a GitHub repo → review the local diff (`git diff <base>...HEAD`) and skip the Copilot lane entirely; no subagent tool → run the review angles sequentially in the main thread. Detect what's available before assuming Copilot access. --- **Invocation:** deliberately model-invocable — "review this PR" phrasing is the trigger. Pushes and issue-creation inside the flow are confirmation-gated. ## Step 1: Assess PR Scope The review target is $ARGUMENTS (a PR number, branch, or URL). If empty, infer it from the conversation or ask. ```bash gh pr view N --json files,additions,deletions,title ``` Categorize: | Tier | Examples | Treatment | |---|---|---| | **Trivial** | Typo, copy edit, single-line deps bump, README polish | Skip multi-agent. Copilot alone is enough. | | **Standard** | Component refactor, single-feature bug fix, contained logic change | Copilot + 1 subagent (pick the angle that matches the risk shape) | | **High-stakes** | Payment, auth, crypto/wallet, RPC, deployment configs, scale-relevant changes, new external SDK integrations | Copilot + 2 parallel subagents minimum (always include adversarial + operational) | If trivial → stop reading this skill, just request Copilot review and ship. --- ## Step 2: Spawn Subagents in Parallel Three angles that empirically work. Pick by risk shape: - **Adversarial** — "Try to break it. What's the worst attack?" Finds security holes, abuse vectors, replay/race conditions, malformed-input handling. - **Operational** — "What fails in production at scale? Latency, cost, observability, timeouts, env config, retries, cold-start?" Finds the architectural P0s line-level review misses (platform execution limits are the canonical class). - **Reference-comparison** — "Does this match the upstream reference impl exactly? Where does it diverge and why?" Use for third-party SDK / spec integration (Phantom deep-link, Stripe, OAuth providers, RPC clients). Spawn all chosen subagents in **a single tool-call batch** so they run in parallel. Prompt templates live in `patterns/subagent-prompts.md`. Every subagent prompt must specify: 1. Repo path (absolute) + branch + commit hash at HEAD 2. Files to focus on (paste the changed-files list from Step 1) 3. Confidence rating + critical findings first 4. Cap report length at ~500 words --- ## Step 3: Request Copilot Review (in parallel with subagents) ```bash gh pr edit N --add-reviewer copilot-pull-request-reviewer ``` Don't wait for Copilot to start before spawning subagents. They run in parallel. --- ## Step 4: Triage Findings Three buckets: **Real findings** — fix now. Push fix to the PR branch. Pushing changes external state: unless the user already asked you to fix or babysit this PR, confirm before the first push of the session. **Stale re-flags** — Copilot will sometimes re-flag findings against unmoved diff lines after fixes ship at HEAD. **Always read the file at HEAD before re-fixing.** If the fix is already there, drop a one-line reply on the comment ("Fixed at <sha>") and move on. Do not re-fix. **Deferred (filed)** — tests, refactors, or work outside scope. File as a GitHub issue (confirm with the user before creating it), link the issue number in the merge commit message, move on. Don't expand the PR. --- ## Step 5: Iteration Cap **Maximum 2 Copilot review rounds.** Empirically, by round 3 the signal-to-noise ratio collapses (~50% stale re-flags). Ship after round 2. If subagents flag genuinely new issues after round 2, those are issue-tracker items, not PR-blockers. --- ## Step 6: When NOT to Use This Skill - **Already-merged PRs** → use Claude Code's built-in `/security-review` if you suspect a problem. - **Trivial-tier PRs** (per Step 1) → just request Copilot, skip the multi-agent overhead. - **PRs where a paid multi-agent service was already run** → don't double-spend. - **Skill / prompt / instruction-file repos** (where the "code" is markdown) → multi-agent is overkill; a single review pass against the trigger-quality and instruction-quality dimensions is enough. --- ## Empirical Evidence Validation case (5 rounds on a high-stakes PR): - **Copilot caught ~10 real line-level issues** (null checks, error handling, type mismatches). - **Subagents caught what Copilot missed across all 5 rounds:** - **P0:** Vercel `maxDuration` not set — function would time out under realistic load. Architectural miss invisible at the line level. - **Persistent-replay vector** in the auth flow. - **Transient poll tolerance** (no retry budget on flaky upstream). - **Env-configurable timeout** (hardcoded value). - **Structured logging** (string-concat logs, unparseable in production). - **`bodyParser` size limit** (DoS surface). - **Round 3+ pattern:** Copilot re-flagged the same already-fixed lines. Confirmed the round-2 cap. Subagents are not redundant with Copilot. They cover a different layer. --- ## Cross-references - `patterns/subagent-prompts.md` — paste-ready prompt templates for the three angles.