Add 'sentry mcp' subcommand to run MCP server in stdio mode

[dcramer]

Add a sentry mcp subcommand that launches the sentry-mcp server in stdio mode, automatically binding the access token from the CLI's existing auth stack — no manual token configuration required.

Current behavior

Users must run sentry-mcp as a separate tool and manually supply an access token. There's no path to launch the MCP server with credentials already managed by the CLI.

Gap

• MCP clients (Claude, Cursor, etc.) need a single shell command to wire up the Sentry MCP server. Wrapping it as sentry mcp gives users a zero-config entry point that reuses their existing sentry login credentials.
• Without this, discoverability and setup friction are high — users have to know about sentry-mcp as a separate package and obtain a token independently.

Implementation notes

• Can be done pre-repo merge by having sentry-cli take a dependency on sentry-mcp (or exec it) and invoking it in --transport stdio mode.
• Auth binding should follow the same resolution order the CLI already uses: stored credentials → SENTRY_AUTH_TOKEN env var.
• MCP client config would simplify to: { "command": "sentry", "args": ["mcp"] }.

--

View Junior Session in Sentry

[linear-code]

CLI-346

[szokeasaurusrex]

Looks like this should have been opened in the new CLI repo

[sentry-junior]

Additional notes from design discussion:

Near-term (before repo merge)

• Add src/commands/mcp.rs — reads auth token from ~/.sentryclirc / SENTRY_AUTH_TOKEN, spawns sentry-mcp (from PATH, falling back to npx @sentry/mcp-server) with SENTRY_ACCESS_TOKEN injected, proxies stdin/stdout transparently
• MCP's resolve-token.ts accepts accessToken directly, so forwarding the CLI token bypasses the OAuth flow cleanly — no separate login step
• npx fallback means zero extra install friction; cost is ~2–5s cold start on first use

Long-term (recommended end state)

• Flip sentry mcp to a Rust stdio↔HTTP bridge that proxies to mcp.sentry.dev (or a configurable endpoint) with Authorization: Bearer <token>
• Tool definitions live on the server — no CLI update needed when MCP gains new tools
• Drops the Node.js dep entirely; ships as a single binary
• Self-hosted users point at their own HTTP MCP endpoint

Repo merge

• Not a blocker for either phase; the HTTP proxy approach makes it largely moot since the CLI just needs to know an endpoint URL
• Only worth revisiting if native Rust MCP tool implementations are desired