Serve an OpenMCP descriptor at /.well-known/openmcp.json (#21)

Spec: https://logicsrc.com/openmcp

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Claude-Session: https://claude.ai/code/session_01SWRffW4ifQPUrGXJtgYWMd

Author: ralyodio

apps/server/public/.well-known/openmcp.json

@@ -0,0 +1,31 @@
+{
+  "openmcp": "0.1",
+  "mcp": "https://tsbb.dev/api/mcp",
+  "name": "tsbb",
+  "description": "A bulletin board for agents and people: boards, threads, replies.",
+  "url": "https://tsbb.dev",
+  "auth": {
+    "kind": "bearer",
+    "url": "https://tsbb.dev/settings"
+  },
+  "tags": [
+    "bbs",
+    "forum",
+    "agents"
+  ],
+  "operator": "https://logicsrc.com/.well-known/openprofile.md",
+  "tools": [
+    "board_overview",
+    "list_forums",
+    "list_topics",
+    "read_topic",
+    "read_post",
+    "search_posts",
+    "get_member",
+    "whoami",
+    "list_notifications"
+  ],
+  "catalogs": [
+    "https://openmcp.logicsrc.com"
+  ]
+}

apps/server/src/routes/discovery.ts

@@ -1,3 +1,6 @@
+import { readFileSync } from 'node:fs';
+import { dirname, join, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
 import { Hono } from 'hono';
 import type { Context } from 'hono';
 import { html } from 'hono/html';
@@ -50,6 +53,9 @@ async function publicForums(): Promise<{ slug: string; name: string; description
     .map((forum) => ({ slug: forum.slug, name: forum.name, description: forum.description }));
 }
 
+const HERE = dirname(fileURLToPath(import.meta.url));
+const PUBLIC_DIR = resolve(HERE, '../../public');
+
 const XML_HEAD = '<?xml version="1.0" encoding="UTF-8"?>\n';
 
 function xml(c: Context<AppEnv>, body: string) {
@@ -340,6 +346,29 @@ export function discoveryRoutes(services: Services) {
     return text(c, lines.join('\n'));
   });
 
+  // --- openmcp.json -----------------------------------------------------------
+  //
+  // The OpenMCP descriptor (https://logicsrc.com/openmcp): where the MCP
+  // endpoint is, how to authenticate to it, and which catalogs list it. Unlike
+  // the files above it is shipped verbatim rather than generated, because it
+  // describes tsbb.dev's MCP server, not this board's forums, and a catalog
+  // verifies the listing by fetching exactly these bytes. It is read on every
+  // request so a redeploy is enough to change it. Public: verification is
+  // done by a catalog with no account here.
+
+  app.get('/.well-known/openmcp.json', (c) => {
+    let body: string;
+    try {
+      body = readFileSync(join(PUBLIC_DIR, '.well-known', 'openmcp.json'), 'utf8');
+    } catch {
+      return c.notFound();
+    }
+    return c.body(body, 200, {
+      'content-type': 'application/json; charset=utf-8',
+      'cache-control': 'public, max-age=300',
+    });
+  });
+
   // --- skill.md ---------------------------------------------------------------
 
   app.get('/skill.md', (c) => {

test/discovery.test.ts

@@ -124,6 +124,18 @@ describe('discovery files and headers', () => {
     await core.setSettings({ 'board.contactEmail': '' });
   });
 
+  it('serves the OpenMCP descriptor verbatim, without a session', async () => {
+    const response = await get('/.well-known/openmcp.json');
+    assert.equal(response.status, 200);
+    assert.equal(response.headers.get('content-type'), 'application/json; charset=utf-8');
+    assert.equal(response.headers.get('cache-control'), 'public, max-age=300');
+
+    const descriptor = (await response.json()) as Record<string, unknown>;
+    assert.equal(descriptor.openmcp, '0.1');
+    assert.equal(descriptor.mcp, 'https://tsbb.dev/api/mcp');
+    assert.ok(Array.isArray(descriptor.tools) && descriptor.tools.includes('board_overview'));
+  });
+
   it('redirects a trailing slash to the one address a page has', async () => {
     const docs = await get('/docs/');
     assert.equal(docs.status, 301);