src/mcp-host.ts

Functions

Imports

It imports no other module of this repo. Imported by src/index.ts, src/security-headers.ts.

Source

1// The MCP endpoint on the family domain ("one address pattern for the family";
2// job_2f9671f89e89, approved as a same-day cut):
3// https://mcp.dustinedwards.info, a Custom Domain on this Worker.
4//
5// That host serves the machine surface and nothing else: the MCP endpoints, the OAuth
6// flow that authorizes them, the /ops routes keys and runners call, the signed backup
7// and bench endpoints, /health and the CSP report sink. Any other path there is the plain 404, so
8// the host never answers with the Portal or a page; the Portal has its own host
9// (src/portal-host.ts). It runs first in the Worker's fetch, with the Portal's rewrite,
10// before the OAuth provider (the lesson of #226).
11//
12// The old address, capsid.dustin-edwards.workers.dev, answers for the hours the cut
13// takes, and then the deploy config turns workers.dev off. Its /portal is retired now:
14// capsid-login no longer lists its sign-in callback, so it is the plain 404, as /console was.
15
16export const MCP_HOST = "mcp.dustinedwards.info";
17export const MCP_URL = `https://${MCP_HOST}/mcp`;
18export const LEGACY_HOST = "capsid.dustin-edwards.workers.dev";
19export const LEGACY_MCP_URL = `https://${LEGACY_HOST}/mcp`;
20
21// Exact paths the MCP host serves, and the prefixes under which it serves everything.
22// "/oauth/clients/verify-live.json" is the verify-live probe's client document
23// (src/oauth-client-docs.ts VERIFY_LIVE_CLIENT_PATH). Live gate 2 fetches it from the
24// host under test (scripts/cimd-probe-lib.mjs); left out, the host answered 404 and the
25// gate rolled back the deploy of 4730307. test/mcp-host.test.ts checks the two agree.
26const MCP_HOST_PATHS = new Set([
27  "/mcp",
28  "/authorize",
29  "/token",
30  "/callback",
31  "/register",
32  "/health",
33  "/csp-report",
34  "/backup/credential",
35  "/bench/tasks",
36  "/bench/draw",
37  "/bench/start",
38  "/bench/repro",
39  "/bench/score",
40  "/shadow/job",
41  "/shadow/result",
42  "/public/model/v1.json",
43  "/public/stats/v1.json",
44  "/public/code/v1.json",
45  "/oauth/clients/verify-live.json",
46]);
47const MCP_HOST_PREFIXES = ["/mcp/", "/ops/", "/.well-known/oauth-"];
48
49export function servedOnMcpHost(pathname: string): boolean {
50  return MCP_HOST_PATHS.has(pathname) || MCP_HOST_PREFIXES.some((p) => pathname.startsWith(p));
51}
52
53/** The Worker's own 404, the same body as the routes handler's fallback. */
54function notFound(): Response {
55  return new Response("not found", { status: 404 });
56}
57
58/** A request the host rules answer at once (the MCP host's unserved paths, the old
59 *  address's retired /portal), or null when the request goes on. */
60export function hostRefusal(request: Request): Response | null {
61  const url = new URL(request.url);
62  if (url.hostname === MCP_HOST && !servedOnMcpHost(url.pathname)) return notFound();
63  if (url.hostname === LEGACY_HOST && (url.pathname === "/portal" || url.pathname.startsWith("/portal/"))) return notFound();
64  return null;
65}