Add an MCP server for the API, deployable next to the application

mcp/ exposes both APIs as MCP tools, one per operation in openapi.yaml,
named after the Laravel route each lands on (public_projects_index,
admin_pages_update, ...). Nothing is written by hand: the tools are
derived from the document the target application serves, which the
contract tests already hold to the truth.

Two transports over one core:

- stdio (`node mcp/server.mjs`), registered in .mcp.json, signing in
  with credentials from the environment and refreshing the token.
- Streamable HTTP (`--http`), stateless, deployed as the landing-mcp
  service. It holds no credentials: each request brings its caller's
  Pireon Basic credentials or bearer token, so the API applies that
  person's permissions. Sessions live in memory keyed by a hash,
  refused credentials are remembered for a minute, and the spec is
  reloaded every minute so new endpoints appear without a redeploy.

Left out on purpose: the token exchange, telemetry, and the contact and
apply forms, which notify real people. The preview secret is never sent
for anonymous callers, and is unset in the deployment by default.

A CI job runs the Node tests, including the HTTP mode end to end
against a fake application.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mcp/test/client.test.mjs

@@ -0,0 +1,151 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+import { LandingClient } from '../src/client.mjs';
+
+const showPage = {
+  method: 'GET',
+  path: '/v1/pages/{page}',
+  params: [{ name: 'page', in: 'path' }, { name: 'lang', in: 'query' }],
+  hasBody: false,
+  requiresAuth: true,
+};
+
+const publicProjects = {
+  method: 'GET',
+  path: '/public/v1/projects',
+  params: [{ name: 'featured', in: 'query' }],
+  hasBody: false,
+  requiresAuth: false,
+};
+
+/** A fake fetch that answers from a list of handlers and records every call. */
+function fakeFetch(handler) {
+  const calls = [];
+
+  const fetch = async (url, init) => {
+    calls.push({ url, ...init });
+    const { status = 200, body = {} } = handler(url, init, calls.length);
+
+    return new Response(status === 204 ? null : JSON.stringify(body), { status });
+  };
+
+  return { fetch, calls };
+}
+
+const tokenResponse = (access, expiresInMs = 3_600_000) => ({
+  access_token: access,
+  refresh_token: `refresh-${access}`,
+  expires_at: new Date(Date.now() + expiresInMs).toISOString(),
+});
+
+test('builds the URL from path and query parameters', async () => {
+  const { fetch, calls } = fakeFetch(() => ({ body: { data: [] } }));
+  const client = new LandingClient({ apiBase: 'http://app.test/api/', fetch });
+
+  await client.call(publicProjects, { featured: true });
+
+  assert.equal(calls[0].url, 'http://app.test/api/public/v1/projects?featured=1');
+  assert.equal(calls[0].headers.Authorization, undefined);
+});
+
+test('sends the preview secret on public calls only', async () => {
+  const { fetch, calls } = fakeFetch((url) => (
+    url.endsWith('/auth/token') ? { body: tokenResponse('a') } : { body: {} }
+  ));
+  const client = new LandingClient({
+    apiBase: 'http://app.test/api', username: 'u', password: 'p', previewToken: 'secret', fetch,
+  });
+
+  await client.call(publicProjects, {});
+  await client.call(showPage, { page: 1 });
+
+  assert.equal(calls[0].headers['X-Preview-Token'], 'secret');
+  assert.equal(calls.at(-1).headers['X-Preview-Token'], undefined);
+});
+
+test('logs in once and reuses the token', async () => {
+  const { fetch, calls } = fakeFetch((url) => (
+    url.endsWith('/auth/token') ? { body: tokenResponse('a') } : { body: { data: {} } }
+  ));
+  const client = new LandingClient({ apiBase: 'http://app.test/api', username: 'u', password: 'p', fetch });
+
+  await Promise.all([client.call(showPage, { page: 1 }), client.call(showPage, { page: 2 })]);
+  await client.call(showPage, { page: 3 });
+
+  assert.equal(calls.filter((c) => c.url.endsWith('/auth/token')).length, 1);
+  assert.equal(calls.at(-1).url, 'http://app.test/api/v1/pages/3');
+  assert.equal(calls.at(-1).headers.Authorization, 'Bearer a');
+});
+
+test('refreshes a token about to expire', async () => {
+  let issued = 0;
+  const { fetch, calls } = fakeFetch((url) => (
+    url.endsWith('/auth/token') ? { body: tokenResponse(`t${++issued}`, 10_000) } : { body: {} }
+  ));
+  const client = new LandingClient({ apiBase: 'http://app.test/api', username: 'u', password: 'p', fetch });
+
+  await client.call(showPage, { page: 1 });
+  await client.call(showPage, { page: 1 });
+
+  const grants = calls.filter((c) => c.url.endsWith('/auth/token')).map((c) => JSON.parse(c.body).grant_type);
+
+  assert.deepEqual(grants, ['password', 'refresh_token']);
+  assert.equal(calls.at(-1).headers.Authorization, 'Bearer t2');
+});
+
+test('retries once with a new token after a 401', async () => {
+  let issued = 0;
+  const { fetch, calls } = fakeFetch((url, init) => {
+    if (url.endsWith('/auth/token')) return { body: tokenResponse(`t${++issued}`) };
+
+    return init.headers.Authorization === 'Bearer t1' ? { status: 401, body: { message: 'Unauthenticated.' } } : { body: { ok: true } };
+  });
+  const client = new LandingClient({ apiBase: 'http://app.test/api', username: 'u', password: 'p', fetch });
+
+  const response = await client.call(showPage, { page: 1 });
+
+  assert.equal(response.status, 200);
+  assert.equal(calls.at(-1).headers.Authorization, 'Bearer t2');
+});
+
+test('falls back to the password when the refresh token is refused', async () => {
+  let issued = 0;
+  const { fetch, calls } = fakeFetch((url, init) => {
+    if (!url.endsWith('/auth/token')) return { body: {} };
+
+    return JSON.parse(init.body).grant_type === 'refresh_token'
+      ? { status: 422, body: { message: 'invalid' } }
+      : { body: tokenResponse(`t${++issued}`, 10_000) };
+  });
+  const client = new LandingClient({ apiBase: 'http://app.test/api', username: 'u', password: 'p', fetch });
+
+  await client.call(showPage, { page: 1 });
+  await client.call(showPage, { page: 1 });
+
+  const grants = calls.filter((c) => c.url.endsWith('/auth/token')).map((c) => JSON.parse(c.body).grant_type);
+
+  assert.deepEqual(grants, ['password', 'refresh_token', 'password']);
+});
+
+test('a fixed token is used as is and never renewed', async () => {
+  const { fetch, calls } = fakeFetch(() => ({ status: 401, body: {} }));
+  const client = new LandingClient({ apiBase: 'http://app.test/api', token: 'fixed', fetch });
+
+  const response = await client.call(showPage, { page: 1 });
+
+  assert.equal(response.status, 401);
+  assert.equal(calls.length, 1);
+  assert.equal(calls[0].headers.Authorization, 'Bearer fixed');
+});
+
+test('refuses an authenticated call without credentials', async () => {
+  const client = new LandingClient({ apiBase: 'http://app.test/api', fetch: async () => assert.fail('no request') });
+
+  await assert.rejects(client.call(showPage, { page: 1 }), /LANDING_TOKEN/);
+});
+
+test('refuses a call missing a path parameter', async () => {
+  const client = new LandingClient({ apiBase: 'http://app.test/api', token: 't', fetch: async () => assert.fail('no request') });
+
+  await assert.rejects(client.call(showPage, {}), /"page"/);
+});