gco-review

name	gco-review
description	Code review using GitHub Copilot CLI. Use when: (1) User says 'gco review' or 'copilot review', (2) After implementation for quality check, (3) Child agents self-reviewing. Runs Copilot to review the diff, synthesizes findings. Falls back to Claude Code if Copilot unavailable.
allowed-tools	["Bash(bash *)","Bash(timeout *)","Bash(gtimeout *)","Bash(node *)","Bash(git *)","Bash(gh *)"]

GCO Review

Code review via GitHub Copilot CLI, synthesized by Claude Code.

Process

Step 0: Pre-flight Rate Limit Check

Before doing anything, check if Copilot is currently in degraded mode:

RATE_CHECK=$(node $HOME/.claude/scripts/gco-rate-limit.js check 2>&1)

If the output starts with degraded:, notify the user that Copilot is in low-cost mode (auto-downgraded model) but proceed with Copilot anyway — it is still usable. Do NOT skip or fall back.

Step 1: Determine Base Branch

BRANCH=$(git branch --show-current)
BASE=$(gh pr view --json baseRefName -q '.baseRefName' 2>/dev/null)

If no PR, use default branch:

BASE=$(git remote show origin | grep 'HEAD branch' | awk '{print $NF}')

Step 2: Build Review Prompt

Generate the diff and build a review prompt:

DIFF=$(git diff "$BASE"...HEAD)

Construct the prompt:

Review the following code changes (diff against $BASE branch).

Focus on:
1. Bugs, logic errors, and potential runtime failures
2. Security vulnerabilities (injection, XSS, auth issues)
3. Performance problems
4. Missing error handling at system boundaries
5. Breaking changes or regressions

For each finding, provide:
- File and approximate location
- Severity (high/medium/low)
- What the issue is and why it matters
- Suggested fix

Be concise. If the code looks good, say so briefly — don't invent problems.

Diff:
<the diff content>

Step 3: Run Copilot

LOGDIR=$(node $HOME/.claude/scripts/get-logdir.js)
mkdir -p "$LOGDIR"
DATETIME=$(date +%Y%m%d_%H%M%S)

bash $HOME/.claude/skills/gco/scripts/gco-run.sh \
  "<prompt>" \
  "$LOGDIR/${DATETIME}-gco-review.md" \
  "$LOGDIR/${DATETIME}-gco-review-stderr.log"

Run as a background Bash task with 15-minute timeout.

Step 4: Collect Results

After Copilot completes (or times out):

1. Read the output file ($LOGDIR/${DATETIME}-gco-review.md)
2. If empty or missing, check stderr log for errors (a 402 no-quota error means Copilot Premium is exhausted — treat it as a failure)
3. If Copilot failed or timed out, jump to Fallback

Step 5: Fallback

If Copilot timed out, produced no usable output, hit no-quota (402), or is not installed:

• Notify the user about the fallback
• Spawn 2 code-reviewer subagents in parallel (like /light-review) to review the diff against $BASE
• Continue as if /light-review was invoked

Step 6: Synthesize and Report

1. Read output and organize findings
2. Categorize by priority (high / medium / low)
3. Present a clear summary
4. Include log file paths for reference

Step 7: Apply Fixes

• High priority: Implement automatically
• Medium priority: Implement if clearly safe, otherwise ask
• Low priority: Ask user

Step 8: Commit Changes

If fixes were applied, commit with a descriptive message.

Important Notes

• Copilot cannot modify files — all writes done by Claude Code
• NEVER use ~ in paths — use $HOME
• Output files: $LOGDIR/${DATETIME}-gco-review.md (timestamped)