ElevenLabs MCP Server

Fetch-native MCP server for ElevenLabs text-to-speech, speech-to-text, voices, and transcripts. It runs on Bun and Cloudflare Workers.

This repository targets the prerelease 2026-07-28 MCP candidate with @modelcontextprotocol/server@2.0.0-beta.5. It does not claim final conformance until the dated specification and stable packages are published and verified.

Tools

• health

• text_to_speech — returns generated audio as a base64 data-URI resource

• speech_to_text — accepts an HTTPS URL or base64 file content

• list_voices

• get_voice

• get_transcript

• delete_transcript

Tool names, inputs, annotations, audio behavior, and transcript behavior are shared across Bun and Workers. Tools that advertise output schemas return matching structuredContent.

Related MCP server: ElevenLabs MCP Server

Configure

bun install
cp .env.example .env

Set the provider credential:

ELEVENLABS_API_KEY=xi_your_elevenlabs_key

This is the only credential sent to api.elevenlabs.io.

Optional MCP caller authentication is separate:

AUTH_STRATEGY=api_key
API_KEY=your_mcp_caller_key
API_KEY_HEADER=x-api-key

API_KEY, BEARER_TOKEN, custom caller headers, and OAuth resource tokens are never reused as ElevenLabs credentials. External JWT Resource Server mode is documented in .env.example.

Run

bun run dev
# http://127.0.0.1:3000/mcp

Cloudflare Workers:

bun x wrangler secret put ELEVENLABS_API_KEY --config wrangler.jsonc
bun run deploy

Set a real MCP_PUBLIC_URL, Host/Origin allowlists, and binding IDs in wrangler.jsonc before deployment.

Protocol and HTTP behavior

• One deployment-scoped fetch handler and a fresh McpServer per request

• Modern protocol pinned to candidate 2026-07-28

• SDK stateless fallback for legacy 2025-11-25 clients

• GET /mcp and DELETE /mcp return 405; no session capability is advertised

• Bounded MCP request bodies, strict Host/Origin checks, and allowlisted CORS headers

• Cancellation reaches ElevenLabs fetches through ctx.mcpReq.signal

Endpoints:

Validate

bun test
bun run typecheck
bun run lint
bun run format:check
bun run build
bun run build:worker
bun run types:worker:check

Provider tests use mocks; real speech generation and transcription require a valid ElevenLabs API key and may incur usage charges.

License

MIT