Copilot CLI

Copilot CLI Agent

When to Use

Use Copilot CLI for:

• GitHub-specific tasks — PRs, issues, repos, Actions, branches, code review
• Git workflow tasks where GitHub context helps
• Tasks where Copilot's GitHub-native tooling is an advantage

Do NOT use Copilot CLI for:

• General code explanations or refactors (handle natively or use Claude CLI)
• Tasks that need your current session context
• When Copilot is not installed or not authenticated

Core Flags

Always combine --no-ask-user --no-auto-update --no-color for clean programmatic output.

Sandbox Limitation

Copilot CLI is sandboxed to its working directory. With --no-ask-user, any file access outside that directory silently fails — no error, no output. There is no --cwd flag; the only fix is to cd to the repo root before invoking.

⛔ Always cd to the repo root before invoking. Never call from a subdirectory.

# ❌ Sandboxed to client/ — reads outside it silently fail
copilot -p "..." --no-ask-user ...

# ✅ Correct — full repo accessible
cd $(git rev-parse --show-toplevel) && copilot -p "..." --no-ask-user ...

Tool Permissions (--allow-tool)

Pre-approves tools so the agent doesn't pause to prompt.

Shell access (shell(...)) is a separate, deliberate decision — not an automatic addition to write access. Only grant it when the task genuinely requires running commands.

Use --deny-tool to block specific commands within an allowed scope:

# Allow git reads but block pushes
--allow-tool='shell(git:*),read' --deny-tool='shell(git push)'

Deny rules always override allow rules.

Model Selection

Model IDs are versioned and change with releases. Run copilot models to get current names, then pick the fastest/cheapest for pings and a capable model for real tasks.

Invocation Patterns

Read-only delegation (question, analysis):

cd $(git rev-parse --show-toplevel) && \
copilot -p "[delegation prompt]" --no-ask-user --no-auto-update --no-color \
  --allow-tool='read' --model=claude-sonnet-4-5

Write delegation (fix, implement):

cd $(git rev-parse --show-toplevel) && \
copilot -p "[delegation prompt]" --no-ask-user --no-auto-update --no-color \
  --allow-tool='write,read' --model=claude-sonnet-4-5

Write delegation + git (runs git commands):

cd $(git rev-parse --show-toplevel) && \
copilot -p "[delegation prompt]" --no-ask-user --no-auto-update --no-color \
  --allow-tool='write,shell(git:*),read' --model=claude-sonnet-4-5

Code review (built-in /review agent):

cd $(git rev-parse --show-toplevel) && \
copilot -p "/review [scope]" --no-ask-user --no-auto-update --no-color \
  --allow-tool='shell(git:*),read' --model=claude-sonnet-4-5

Redirect stderr if needed: add 2>/dev/null

Delegation Prompt

Copilot CLI has no --append-system-prompt flag, so CortexLink agent context must be prepended to every delegation prompt. Always open every delegation prompt with this block:

You are operating as a CortexLink agent. Your output is consumed directly by a control center — not displayed to a user. Execute the task, verify your own work (Execute → Verify → fix if needed → Report), then return ONLY the structured report below. No reasoning steps, no "Let me..." output before the report.

---

[Task]: ...

The report format goes at the end (from the delegation template). The opening block teaches the agent the protocol — the closing block specifies this task's expected output.

⛔ Critical: Never omit the opening CortexLink agent context block. Without it, Copilot CLI has no way to learn the report format or self-verify protocol.

Handling the Report

The agent's stdout is its report. Capture it directly:

REPORT=$(cd $(git rev-parse --show-toplevel) && \
  copilot -p "[prompt]" --no-ask-user --no-auto-update --no-color \
  --allow-tool='read' --model=claude-sonnet-4-5 2>/dev/null)

Read STATUS first. If ⚠️ or ❌, read ISSUES before deciding next action.

Error Handling

Chaining

Pass the SUMMARY + STEPS excerpt from this agent's report as [Context] in the next delegation prompt. Do not pass raw output.