GitHub Copilot

GitHub Copilot reads repository hooks from .github/hooks/*.json: Copilot CLI, the Copilot cloud agent and VS Code agent mode all load them. comity init --tools copilot writes one hooks file plus MCP config for Copilot CLI and VS Code.

Set up

cd your-repo
comity init --tools copilot
git add .github/hooks/comity.json .github/mcp.json .vscode/mcp.json
git commit -m "Set up Comity for GitHub Copilot"

Then:

• Copilot CLI: run comity login once, then start copilot in the repo and confirm folder trust. Copilot CLI loads repository hooks and MCP servers only in trusted folders.
• VS Code: open .vscode/mcp.json and start the comity server.
• Copilot cloud agent: see Cloud agent.

What init writes

.github/hooks/comity.json

Events use PascalCase names, so Copilot sends the VS Code–compatible payload (snake_case fields, Claude tool names such as Bash and Edit). Each handler has a POSIX bash command and a powershell variant for Windows. Shown for one event:

{
  "version": 1,
  "hooks": {
    "PreToolUse": [
      {
        "type": "command",
        "command": "command -v comity >/dev/null 2>&1 || exit 0; exec comity hook --tool copilot --event PreToolUse",
        "bash": "command -v comity >/dev/null 2>&1 || exit 0; exec comity hook --tool copilot --event PreToolUse",
        "powershell": "$c = Get-Command comity -CommandType Application -ErrorAction SilentlyContinue | Select-Object -First 1; if (-not $c) { exit 0 }; & $c.Source hook --tool copilot --event PreToolUse",
        "timeout": 5,
        "matcher": "Bash|Edit|Write|bash|powershell|create|edit|str_replace_editor|apply_patch|run_in_terminal|create_file|replace_string_in_file|multi_replace_string_in_file|insert_edit_into_file"
      }
    ]
  }
}

Copilot preToolUse command hooks fail closed: a crash or non-zero exit denies the tool call. Both command variants exit 0 when the CLI isn't installed, and comity hook always exits 0.

.github/mcp.json (Copilot CLI)

{
  "mcpServers": {
    "comity": { "type": "local", "command": "node", "args": ["-e", "<launcher>", "mcp"], "tools": ["*"] }
  }
}

.vscode/mcp.json (VS Code)

{
  "servers": {
    "comity": { "type": "stdio", "command": "node", "args": ["-e", "<launcher>", "mcp"] }
  }
}

Both start comity mcp, a local stdio bridge to the Comity server, through a short node -e launcher (<launcher> above) that finds comity on any OS. The files are identical for every teammate, whatever OS ran comity init, and Node must be on PATH. The bridge uses the login stored by comity login (or COMITY_TOKEN/COMITY_SERVER when set), so no token goes into the repo and nothing has to be exported or pasted. comity doctor warns about comity mcp or cmd /c comity mcp entries written by an earlier init, because each works on one OS only.

Other servers and inputs in these files are kept. Rerunning init replaces an older token-based comity entry and removes the comity-token prompt it added to .vscode/mcp.json.

What your agent sees

• Session start: the briefing as additionalContext.
• Before a shell command or file edit: a block denies the call (permissionDecision: "deny") with Comity's reason. The hook prints both Copilot's top-level fields and VS Code's hookSpecificOutput.
• After a tool call: new conflicts, messages and notices as additionalContext.
• Prompts and pre-tool warnings: Copilot ignores the output of prompt hooks, and preToolUse can't add context. These warnings are queued for the next tool result.

Cloud agent

The cloud agent runs .github/hooks/*.json from the repository in its Linux sandbox. The bash command exits quietly unless comity is installed there. To coordinate cloud agent jobs:

1. Install the CLI in copilot-setup-steps.yml (npm i -g https://api.comity.so/cli/comity-cli.tgz).
2. Add COMITY_TOKEN as a secret in the repository's copilot environment.
3. Add the MCP server in the repository's Settings → Copilot → Cloud agent → MCP configuration. The cloud agent doesn't read .github/mcp.json, and MCP secrets must start with COPILOT_MCP_:

{
  "mcpServers": {
    "comity": {
      "type": "http",
      "url": "https://api.comity.so/mcp",
      "headers": { "Authorization": "Bearer $COPILOT_MCP_COMITY_TOKEN" },
      "tools": ["*"]
    }
  }
}

Organization admins can also manage MCP servers for the cloud agent at the organization level.

Sessions report the cloud surface.

Claude Code hooks in Copilot CLI

Copilot CLI also runs .claude/settings.json hooks. When the repo or ~/.copilot/hooks/ has a hooks file calling comity hook, the invocation from .claude/settings.json steps aside, so each event is evaluated once. Repos set up only for Claude Code keep working in Copilot CLI through that import.

Verify

comity doctor

Expect copilot hooks all 6 events installed, copilot mcp configured in …/.github/mcp.json and vscode mcp configured in …/.vscode/mcp.json. In Copilot CLI, /mcp should list comity as connected.

Limits

• Prompt-time briefings arrive after the next tool call, because Copilot drops the output of prompt hooks.
• A command preToolUse hook that times out lets the tool call through.
• .vscode/mcp.json servers that use ${input:…} aren't forwarded to Copilot CLI sessions started from VS Code. Those sessions use .github/mcp.json.