ConferenceCaptioning MCP server

ConfCapMcp

A read-only MCP server for ConferenceCaptioning. It lets an AI assistant read your stream's live captions and translations, your saved transcripts and your audience questions, using a developer API key you create in the portal.

Privacy: everything a tool returns is sent to the AI model you connected. If you promised attendees that captions stay private, check that model provider's terms first.

Setup

1. In the portal (https://app.deafassistant.com), open Advanced Settings and choose Create Developer API Key. Copy the key (it is shown once). It is read-only, and you can delete it any time.
2. Build: npm install && npm run build.
3. Add the server to your client. Claude Desktop (claude_desktop_config.json) or any stdio MCP client:

{
  "mcpServers": {
    "confcap": {
      "command": "node",
      "args": ["/path/to/ConfCapMcp/dist/src/index.js"],
      "env": { "CONFCAP_KEY": "cck_...", "CONFCAP_STREAM": "yourstream" }
    }
  }
}

Claude Code: claude mcp add confcap -e CONFCAP_KEY=cck_... -e CONFCAP_STREAM=yourstream -- node /path/to/ConfCapMcp/dist/src/index.js

Variable	Meaning
CONFCAP_KEY	Your developer API key. Needed for saved transcripts, questions and your secured streams. Not needed for public streams.
CONFCAP_STREAM	Default stream name. If unset and the key owns exactly one stream, that stream is used.
CONFCAP_AUTH	The secure code of a secured stream, to read its captions without being its owner.
CONFCAP_API_URL	Defaults to https://api.deafassistant.com. Must be https (or localhost).

Keep the key out of source control. See the Developer API docs.

Hosted mode

MCP_TRANSPORT=http PORT=8787 node dist/src/index.js runs a stateless streamable-HTTP endpoint (POST /mcp, GET /healthz) instead of stdio. Each request carries its own key (Authorization: Bearer cck_...), optionally X-Confcap-Stream and X-Confcap-Auth. Nothing is stored; callers never share cached text; 60 requests a minute per caller. Self-hosting as a systemd service behind nginx, with memory and CPU caps, is in deploy/README.md.

Connect a client to the hosted server (nothing to install)

The hosted endpoint is https://mcp.deafassistant.com/mcp. Create a key in the portal (step 1 above), then:

• Claude Code: claude mcp add --transport http confcap https://mcp.deafassistant.com/mcp --header "Authorization: Bearer cck_..." (add --header "X-Confcap-Stream: yourstream" to set a default stream).
• Claude Desktop (tested): Settings > Connectors > Add > Add custom connector. Name ConferenceCaptioning, MCP server URL https://mcp.deafassistant.com/mcp, then Continue. It reports "no sign-in" (we do not use OAuth); open Request headers, add the header Authorization with the value Bearer followed by your key, and click Add. Then start a chat and ask "what can the ConferenceCaptioning connector do".
• Any other client with remote MCP and custom headers: the same URL with the header Authorization: Bearer cck_.... Clients that only offer OAuth sign-in cannot send a static header yet.
• Clients that only speak stdio: npx mcp-remote https://mcp.deafassistant.com/mcp --header "Authorization: Bearer cck_..." bridges to the hosted URL.

The key is sent on every request, so treat the client's config file like a password file. Check the connection with HOSTED_URL=https://mcp.deafassistant.com node scripts/live-smoke.mjs (needs a portal login and FIREBASE_API_KEY, see below).

Listing in the MCP Registry

server.json describes the hosted server for the official MCP Registry (a remote, streamable-http server that needs an Authorization header). It is published by the "Publish to the MCP Registry" workflow (.github/workflows/publish-registry.yml) through GitHub's OIDC login, because an organization namespace (io.github.TheFirstPrototype) cannot be published from a laptop's mcp-publisher login github. Push a tag such as v0.1.0 (the tag becomes the version), or run the workflow by hand. The registry checks that you control the namespace, not the server URL.

Tools

Tool	What it does	Needs a key
list_my_streams	The streams the key can read	yes
get_session_overview	Start here: what exists for a stream (live or probably stopped, live text held, saved transcripts, questions, glossary) and what to do next	no (more with a key)
get_stream_status	Live or not, languages, and whether it is readable (ok, authRequired, expired, unknown)	no
get_live_captions	Newest caption text, spoken language or a translation; a cursor for new text only	no (yes for your secured streams)
get_stream_context	Colour, logo and glossary terms (use them to correct mis-heard names)	no
list_saved_transcripts	Saved transcripts with title, note, times and length	yes
get_saved_transcript	One transcript, paged	yes
list_questions	Audience questions, oldest first	yes
get_audience_summary	Visits to the attendee page: totals, peak, cities, referrers, devices	yes
get_help_links	Links to the how-to guides (static)	no

Also: resources confcap://stream/{name}/status and confcap://stream/{name}/transcript/{id}, and prompts meeting_minutes, triage_questions, catch_me_up, translate_summary.

Good to know:

• Translations are a window of recent text that is re-translated as people speak. Saved transcripts are in the spoken language only; ask the assistant to translate them.
• Only some streams store history, and only sessions of 100 characters or more.
• Speech and questions come back wrapped in <untrusted-text>: other people wrote them, so a model should treat them as data, never as instructions.

Safety properties (all tested)

• Only GET requests. The server has no code path that writes or deletes, and the key is read-only on the server as well.
• Credentials come only from the environment, never from tool arguments. They are redacted from errors and never logged.
• The account uid and the admin code are never used or sent.
• Calls to one stream are spaced at one per second and overall at five per second; 429 and 5xx are retried with backoff.
• Two server instances never share cached text.

Live smoke test (stdio, or HOSTED_URL=https://... node scripts/live-smoke.mjs for the hosted endpoint)

Runs the built server against the real API with a throwaway key (created and deleted by the script), calls every tool read-only, and checks that neither the key nor the account uid appears in any output.

npm run build
FIREBASE_API_KEY='portal Firebase web apiKey' T_EMAIL='<portal login of an account that owns a stream>' T_PASS='<password>' npm run live-smoke

Optional: SMOKE_STREAM (default: the account's first stream), API_BASE_URL. Exit code 0 means it passed. Never commit the password. The related checks are ConfCapApi/scripts/live_developer_keys_check.py (API) and ConfCapPortal/e2e (portal UI).

Development

npm test builds and runs the tests (a real local mock API, the protocol through the SDK's in-memory transport, and mutation-style checks described in test/). The server uses the v1.x SDK, which supports the 2025-11-25 MCP spec.