MCP server for coding agents (F22)

[jainath]

Summary

Adds an opt-in, loopback-only HTTP MCP server so coding agents (Claude Code, Cursor, anything that speaks MCP) manage the user's dev servers through DevHarbor instead of spawning npm run dev in a shell they then lose track of. Processes started this way outlive the agent's session, stay visible in the app, and get logs, port tracking, readiness checks, and clean shutdown for free.

22 tools: list / add / update / remove apps · add / remove tasks · start / stop / restart apps and individual tasks · read / search logs · inspect ports, env vars, run history, node versions · scan folders · configure readiness probes.

Off by default. Enable under Settings → MCP server (status, port, token, copy-paste client config). Version bumped to 1.2.0.

Highlights

• Security posture: binds 127.0.0.1 only (not configurable), validates Host/Origin on every request, requires a bearer token by default (sha256 + timingSafeEqual, never logged). Secret env values are masked in responses and redacted from log output. Optional HTTPS via a self-signed localhost certificate generated on first use.
• Honest readiness: a probe-less task reports ready: null instead of a vacuous true; a factual listening flag is reported separately from verified ready; start results carry readinessVerified plus recent output so an agent can judge for itself; a new http readiness kind polls /health until a service can actually serve; set_readiness lets an agent configure a probe. Each detected port is labeled with its owning process, and the start path waits for the port set to stabilize so slow-binding monorepo siblings are captured inline.
• Monorepos: add_app with workspaceTasks: true registers a repo once with one task per workspace package (pnpm/yarn/npm, same detection as the UI); add_task / remove_task shape the task set with per-task working directory, dependsOn ordering (migrate → api → web), and oneShot for migrations/builds. Workspace globs that escape the repo root are rejected so a task can never run an unrelated sibling project.
• Live UI: MCP mutations push a state:invalidate event so the desktop reflects add/remove/start/stop without a manual reload.

Implementation notes

• New src/main/mcp/ module: stateless Streamable HTTP transport (@modelcontextprotocol/sdk, per-request server), pure gate.ts (Host/Origin/bearer), hygiene.ts (ANSI strip + secret redaction), token.ts, tls.ts.
• Shared AppOps de-duplicates the create/update/remove/scan/search flows between the existing IPC handlers and MCP.
• New settings keys mcp_enabled / mcp_port / mcp_require_auth / mcp_https.
• Design and full tool catalog: specs/07-mcp-server.md.

Testing

• 143 unit tests (vitest): gate, hygiene, resolver, TLS, HTTP readiness, and the full 22-tool catalog against a fake context — no electron/better-sqlite3 imports in the unit suite.
• Live E2E: an Electron harness drives the real packaged server with the SDK client (functional + auth/403/405/413), plus a monorepo run against a pnpm fixture (per-package registration, per-service start/stop, dependency-ordered oneShot, an http probe verifying a slow-boot API, guard rejections) — all 25 checks pass against the built binary.
• Multiple adversarial multi-agent review rounds; all confirmed findings fixed.
• typecheck clean · lint 0 · 143/143 tests.

Release notes

The local build is signed with a Developer ID but not notarized (no Apple creds in the build env). The real release should go through the v1.2.0 tag → CI workflow, which notarizes and publishes.