| name | gco |
| description | Run GitHub Copilot CLI as a read-only sub-agent from Claude Code. Use when: (1) User says 'gco', 'copilot', or 'ask copilot', (2) Delegating code review or research to Copilot, (3) Getting a second opinion on code or architecture. Read-only mode (no file writes), gpt-5.4 model. |
| user-invocable | true |
| argument-hint | <prompt> |
| allowed-tools | ["Bash(bash *)","Bash(timeout *)","Bash(gtimeout *)","Bash(node *)"] |
GitHub Copilot Read-Only Sub-Agent
Run GitHub Copilot CLI in read-only mode for code review, research, and investigation tasks.
How It Works
- Copilot runs non-interactively with
-p (prompt) and -s (silent output)
- Read-only enforced via
--deny-tool='write' (hard tool-level block) and read-only preamble in prompt
- Uses
--no-ask-user and --allow-all-tools for fully autonomous execution
- Model:
gpt-5.4
- Timeout: 15 minutes
Process
Step 1: Build the Prompt
Take the user's request and use it as the copilot prompt. If the user provides /gco with arguments, use those as the prompt directly.
Step 2: Run Copilot
LOGDIR=$(node $HOME/.claude/scripts/get-logdir.js)
mkdir -p "$LOGDIR"
DATETIME=$(date +%Y%m%d_%H%M%S)
SLUG="<short-topic-slug>"
bash $HOME/.claude/skills/gco/scripts/gco-run.sh \
"<prompt>" \
"$LOGDIR/${DATETIME}-gco-${SLUG}.md" \
"$LOGDIR/${DATETIME}-gco-${SLUG}-stderr.log"
Run as a background Bash task with 15-minute timeout.
Step 3: Collect and Present Results
- Read the output file (
$LOGDIR/${DATETIME}-gco-${SLUG}.md)
- If empty or missing, check stderr log for errors — a no-quota (402) error means Copilot Premium is exhausted; report it and fall back to Claude Code tools
- Synthesize and present findings to the user
- Include the log file path for reference
Important Notes
- Copilot cannot modify files — all writes are done by Claude Code
- NEVER use
~ in paths — use $HOME
- Output and stderr go to
$LOGDIR/${DATETIME}-gco-* (timestamped)
- If copilot is not installed, report "Copilot CLI not found. Install with: gh extension install github/gh-copilot" and fall back to Claude Code tools
