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Copilot cloud agent: Preloop MCP on GitHub.com

Editions: OSS, Cloud, Enterprise. Unless stated otherwise, everything on this page ships in OSS.

Repository admins can give the Copilot cloud agent on GitHub.com access to Preloop tools by pasting an MCP config into the repository's Copilot MCP settings. There is no local config for preloop agents discover to rewrite. This page covers that GitHub.com path only. It does not cover inline completions or IDE Copilot chat. Every Copilot surface, including this one, is in Copilot coverage.

Configure MCP servers under Settings → Copilot → MCP servers. Official steps: https://docs.github.com/en/copilot/how-tos/copilot-on-github/customize-copilot/configure-mcp-servers

MCP configuration

Store a Preloop API token as an Agents secret named COPILOT_MCP_PRELOOP_TOKEN (names must start with COPILOT_MCP_). Do not put the token in the JSON. GitHub substitutes $COPILOT_MCP_* references in header values.

Replace the URL host with your Preloop instance (PRELOOP_URL):

{
  "mcpServers": {
    "preloop": {
      "type": "http",
      "url": "https://preloop.example.com/mcp/v1",
      "headers": {
        "Authorization": "Bearer $COPILOT_MCP_PRELOOP_TOKEN"
      },
      "tools": ["*"]
    }
  }
}

Prefer a tighter tools allowlist once you know which Preloop tools the agent should call. Copilot calls the tools you list without asking for approval on GitHub. Preloop still applies its own tool policy on /mcp/v1.

The same repository MCP configuration, including the Agents secret, is shared with Copilot code review. Code review only calls tools whose tools/list entries set annotations.readOnlyHint to true. Turn that off under Settings → Copilot → Code review if review sessions should not see these tools.

Firewall allow list

The cloud agent sandbox only reaches hosts on the Copilot firewall allow list. Add the Preloop hostname (the host in PRELOOP_URL) or the agent cannot open {PRELOOP_URL}/mcp/v1.

Model traffic

Model calls from the cloud coding agent stay on GitHub-hosted models. This page does not route them through the Preloop gateway, and it does not install a local Copilot CLI.

Hooks

.github/hooks/*.json can emit session lifecycle events from the cloud agent (see GitHub's hooks reference). Preloop does not install those hooks. An http hook back to Preloop also needs the Preloop host on the firewall allow list. Files a hook writes inside the sandbox are discarded when the job ends.