Support external MCP servers in the review agent

[schibrikov]

Request to let the Warden review agent call external MCP servers during skill execution.

Use case: pull task descriptions and comments from a Linear ticket so the agent can check code against requirements.

Current state: Warden exposes an MCP server for IDE integration, but the review agent does not consume external MCP servers.

Workaround: use the Linear CLI or API directly.

[sentry-pierre]

I cleaned up the title and body to make the distinction clearer: Warden already exposes itself as an MCP server, but this request is about the review agent consuming external MCP servers.

What I checked:

• .mcp.json, agents.toml, and .cursor/mcp.json configure Warden as an MCP server for IDEs.
• packages/warden/src/config/schema.ts has no MCP client configuration.
• packages/warden/src/sdk/runtimes/ only handles built-in tools (Read, Bash, etc.).

A maintainer can take it from here.

[dcramer]

MCP will be a little tricky - would require service-level/headless auth, and Warden doesn't generally have access to that kind of thing

[schibrikov]

Yeah, auth is definitely a challenge there.
Some use-cases might be covered without a direct support for auth though, and maybe users could find workarounds at their own risk (provide service token in env or something). But that's a bit of a half-baked solution ofc.