Intern MCP

Local stdio MCP server for working on Intern-hosted sites through guarded Git checkouts.

Install in a coding harness

Intern MCP is packaged for distribution as the public @archastro/intern-mcp npm package. It requires Node.js 22 or newer. The explicit scoped registry override keeps installation working on machines that route @archastro elsewhere.

Codex

codex mcp add intern -- \
  npx --yes --@archastro:registry=https://registry.npmjs.org \
  @archastro/intern-mcp@0.1.0 serve
codex mcp get intern

Restart Codex after adding the server. Codex stores the stdio command in its user configuration and starts the package when a session needs the server.

Claude Code

claude mcp add --transport stdio --scope user intern -- \
  npx --yes --@archastro:registry=https://registry.npmjs.org \
  @archastro/intern-mcp@0.1.0 serve
claude mcp get intern

The user scope makes Intern available in every Claude Code project. Use --scope local instead if it should only be available in the current project. Run /mcp inside Claude Code to inspect the connection.

The two harnesses launch the same local stdio executable. Authentication still uses intern_login and the TryIntern device page; no OAuth secret or service credential is placed in harness configuration.

Upgrades are explicit: remove the existing registration and add it again with the reviewed version replacing 0.1.0:

codex mcp remove intern
claude mcp remove intern

Then rerun the corresponding command above. The harness never executes a newly published package version merely because it restarted.

The repository is private and the npm package has not been published yet. The commands above become available after the first package release.

Maintainers run the manual release workflow to publish the version in package.json. The first release uses a short-lived NPM_TOKEN repository secret in the protected npm-release environment because npm cannot attach a trusted publisher to a package that does not exist. That environment accepts only protected branches; main itself requires CI and approving review. After 0.1.0, configure ArchAstro/intern-mcp, release.yml, and environment npm-release as the npm trusted publisher, remove the secret, and later runs authenticate with GitHub OIDC.

Related MCP server: codex-web-bridge

Configure the server

Production public values are built in:

• TryIntern origin: https://tryintern.dev

• ArchAstro API: https://platform.archastro.ai

• OAuth client: cc_vuMmqN4VbAKy8zsWRYorUg, with only profile scope

• TryIntern's public ArchAstro publishable key

The OAuth client secret is not used by this device-flow public client. Do not put it in MCP or TryIntern configuration.

These optional environment values override the defaults for local testing or custom workspace setup:

• INTERN_BASE_URL — Intern frontend origin.

• ARCHASTRO_API_URL — ArchAstro API origin.

• ARCHASTRO_PUBLISHABLE_KEY — Intern app publishable key.

• INTERN_OAUTH_CLIENT_ID — alternate device-flow client registered with only profile scope.

• INTERN_WORKSPACE_ROOT — parent directory for <org>/<site> checkouts.

• INTERN_GIT_SSH_COMMAND — optional per-process SSH command for development or custom SSH setup.

• INTERN_IAP_ID_TOKEN (or IAP_ID_TOKEN) — Google ID token for the IAP-protected production frontend. It is sent through Proxy-Authorization while the ArchAstro bearer remains in Authorization.

For development from this repository, install and build with:

npm ci
npm run build

Then configure an MCP host to run:

node /absolute/path/to/intern-mcp/dist/index.js serve

For Codex, the checkout-based equivalent is:

codex mcp add intern \
  --env INTERN_WORKSPACE_ROOT=/absolute/path/to/Intern \
  -- node /absolute/path/to/intern-mcp/dist/index.js serve

Use intern_login, approve the browser prompt, and call intern_complete_login. Then use intern_prepare_site and edit the returned absolute path with the coding host's normal filesystem tools. The prepare result includes validation against the authenticated Intern runtime contract.

Run against a local Firstlanding stack

The backend still lives in Firstlanding. With Aster 0.11.1 or newer, start one Intern topology in that worktree and point this repository's launcher at it:

# Terminal 1, from the Firstlanding worktree
aster services up intern

# Or run intern-data on this machine
# aster services up intern-local

# Terminal 2, from this repository
INTERN_PLATFORM_WORKSPACE=../firstlanding-wt2 scripts/run-local.sh

INTERN_PLATFORM_WORKSPACE identifies the exact worktree whose Aster supervisor owns the local ports. The supervisor remains attached while the MCP launcher connects to it.

Each Intern group owns Platform, TryIntern, control, and the Git gateway under one atomic Aster port allocation. The launcher uses aster --json services ports; it does not assume the default Platform, TryIntern, or Git gateway SSH ports. Both Intern topologies expose the same API and Git contract to the MCP; only the control plane's site provider changes. For local Git, the launcher routes git.intern.dev SSH traffic to the reported loopback gateway port. The launcher loads the local publishable key and profile-only OAuth client from .env.intern.local, builds the MCP, and keeps its local credentials and site checkouts under this repository's ignored tmp/ directory. INTERN_CONFIG_ROOT and INTERN_WORKSPACE_ROOT still override those paths. Test harnesses can set INTERN_LOCAL_ENV_FILE to load a different local public-client configuration. If the worktree's ports changed, the launcher prints the exact command that reconciles the local OAuth client's device verification URI before starting.

The same launcher exposes the standalone commands for manual checks:

INTERN_PLATFORM_WORKSPACE=../firstlanding-wt2 scripts/run-local.sh login
INTERN_PLATFORM_WORKSPACE=../firstlanding-wt2 scripts/run-local.sh status
INTERN_PLATFORM_WORKSPACE=../firstlanding-wt2 scripts/run-local.sh logout

After edits, call intern_test_site before committing. It validates tracked and untracked working-tree files, excludes ignored files, and returns an ephemeral http://127.0.0.1:<port> preview URL. The URL serves a temporary snapshot, so call the tool again after further edits. intern_stop_test stops it without needing the backend or a current login. Logout and stdio shutdown also stop every preview and remove its snapshot.

Once the local result is correct, commit the change and call intern_validate_site. It checks the exact committed tree: required and protected runtime files, dependencies the backend does not install, JavaScript syntax, production-style startup, and an HTTP probe. intern_publish_site reruns the same commit validation and refuses invalid or dirty worktrees. The MCP never stages or commits files.

For each SSH clone or push, Intern MCP creates or reuses one local Ed25519 key and sends only its public half to Intern. Intern returns a five-minute user certificate plus the pinned git.tryintern.dev host key. MCP supplies those files only to that Git process; it never edits global Git config, ~/.ssh/config, or the user's known_hosts. Logout removes the current certificate but retains the private key for future short-lived certificates.

The current runtime contract is deliberately narrow: Intern runs its protected server.mjs through run-site.sh, supplies PORT, and does not install package dependencies. A model can edit HTML, CSS, browser JavaScript, and assets. Runtime launcher changes are rejected because the current Git publish path does not restart the site process.

In production, intern-fe authenticates to private intern-ctl gRPC with a Google service-account ID token bound to the control audience and forwards actor fields only after resolving the user at the HTTPS edge. Aster uses an explicit archastro-dev override. Git clone and publish use the short-lived SSH user certificates described above. The local launcher overrides that path for Aster's development gateway; an explicit INTERN_GIT_SSH_COMMAND still takes precedence.

Development checks

Run the complete local gate from the repository root:

npm run check

It checks formatting and lint, builds TypeScript, runs the test suite, packs the npm artifact, installs it into a clean temporary consumer, launches its installed binary over real MCP stdio, and lists its tools. The CI also installs the pinned Codex and Claude CLIs and runs npm run test:harnesses. That proof asks both real harnesses to register the tarball in isolated temporary user profiles; Claude must connect successfully. The script never changes the operator's real Codex or Claude configuration.

Runtime-contract fixture

Firstlanding's services/go/intern-data/internal/sites/runtime-contract.json owns the backend contract. This repository keeps a byte-for-byte fixture so its fail-closed parser, validator, and Git tests exercise the current protected runtime. When the backend contract changes, update the two repositories in the same change set:

node scripts/runtime-contract.mjs sync ../firstlanding-wt2
npm run check:runtime-contract -- ../firstlanding-wt2
npm run check

Firstlanding's canonical scripts/intern/e2e-local.sh crosses the live backend and this sibling checkout. It is the compatibility proof; the fixture is not a second source of truth.