OpenTranscribe MCP

Own the recorder. Choose the intelligence.

OpenTranscribe is an open-source MCP server that routes audio to the speech-to-text model of your choice and returns one provider-independent transcript schema.

It is built around a simple idea: buying a great recorder should not lock you into one transcription subscription. Use Plaud, a phone, an open-source wearable, or any other audio source you are authorized to access, then choose Microsoft MAI, ElevenLabs Scribe, or Groq Whisper without changing the downstream workflow.

OpenTranscribe does not jailbreak hardware or bypass access controls. It works only with audio the operator is authorized to access.

How it works

OpenTranscribe keeps the integration boundary stable: the recorder supplies an audio file or HTTPS URL, the server selects or calls the requested speech-to-text provider, and downstream tools receive the same canonical transcript shape.

What v0.1 ships

• MCP Streamable HTTP at /mcp, with stateless operation and bearer authentication
• transcribe_audio, list_transcription_models, estimate_transcription_cost, get_transcript_chunk, and delete_transcript
• Microsoft MAI-Transcribe-2, ElevenLabs scribe-v2, and Groq Whisper adapters
• explicit capability negotiation, routing policies, retries, and observable fallbacks
• HTTPS URL passthrough when supported and a bounded streaming proxy otherwise
• SSRF controls, signed-URL redaction, zero content logging, and cost/resource limits
• disabled-by-default retention; optional memory or S3-compatible temporary result storage
• Docker, Scaleway Serverless Containers guidance, tests, and GitHub Actions CI

Ten-minute quickstart

Requirements: Python 3.12 and uv, or Docker.

git clone https://github.com/fbossiere/open-transcribe-mcp.git
cd open-transcribe-mcp
cp .env.example .env

Edit .env with one provider credential and a strong random MCP bearer token. For Microsoft:

OT_MICROSOFT__ENDPOINT=https://YOUR-RESOURCE.cognitiveservices.azure.com
OT_MICROSOFT__API_KEY=YOUR-KEY
OT_SECURITY__BEARER_TOKEN=YOUR-RANDOM-TOKEN

Start the server:

uv sync
uv run open-transcribe-mcp

The MCP endpoint is http://localhost:8000/mcp; probes are available at /healthz and /readyz.

Connect a FastMCP client:

import asyncio
from fastmcp import Client


async def main() -> None:
    async with Client("http://localhost:8000/mcp", auth="YOUR-RANDOM-TOKEN") as client:
        models = await client.call_tool("list_transcription_models", {})
        print(models)
        result = await client.call_tool(
            "transcribe_audio",
            {
                "request": {
                    "source": {"type": "url", "url": "https://example.org/authorized-audio.mp3"},
                    "provider": "auto",
                    "routing_policy": "quality",
                    "diarization": True,
                    "timestamps": "segment",
                    "transcript_style": "clean",
                }
            },
        )
        print(result)


asyncio.run(main())

Provider choice does not alter the response contract. Set provider and model to switch explicitly, or use auto with default, quality, cost, or latency routing.

Docker

docker build -t open-transcribe-mcp:0.1.1 .
docker run --rm -p 8000:8000 \
  -e OT_ENVIRONMENT=prod \
  -e OT_MICROSOFT__ENDPOINT="https://YOUR-RESOURCE.cognitiveservices.azure.com" \
  -e OT_MICROSOFT__API_KEY="YOUR-KEY" \
  -e OT_SECURITY__AUTH_MODE=bearer \
  -e OT_SECURITY__BEARER_TOKEN="YOUR-RANDOM-TOKEN" \
  open-transcribe-mcp:0.1.1

Configuration

All settings use the OT_ prefix and __ for nesting. See .env.example. Provider credentials are server-side environment variables and are never accepted as MCP tool arguments.

Temporary storage is disabled by default. result_mode=stored requires:

OT_RESULT_STORE__BACKEND=memory  # local/test only; use s3 for horizontally scaled production
OT_RESULT_STORE__CURSOR_SECRET=ANOTHER-RANDOM-SECRET

For Scaleway Object Storage, install the s3 extra and configure the S3 bucket/endpoint variables documented in the deployment guide.

Security and privacy defaults

• source HTTPS is required;
• private, loopback, link-local, multicast, reserved, and metadata destinations are rejected;
• every redirect target is resolved and validated;
• source downloads are streamed to an ephemeral file with byte limits, then deleted;
• signed URL queries, audio, transcript text, authorization headers, and phrase hints are not logged;
• no project telemetry is emitted;
• transcripts are not retained unless a result store is explicitly enabled and used.

Read SECURITY.md, the threat model, and the retention policy before exposing the service publicly.

Known limitations

OpenTranscribe v0.1 targets self-hosted, single-tenant installations. Provider feature parity is deliberately not guaranteed; capability negotiation exposes differences instead of hiding them. URL ingestion is the only remote input type. Synchronous provider limits still apply. OIDC and asynchronous jobs are planned for later releases. The memory store is neither durable nor horizontally scalable. S3 lookups prioritize a simple deployment contract over very-large-bucket indexing; dedicate the result prefix and enforce lifecycle deletion.

DNS is validated immediately before source requests and on every redirect. The stock HTTP transport still performs its own connection-time resolution, so operators with a high-assurance threat model should combine host allow-listing with egress firewall rules.

Provider prices, APIs, and capabilities change. The checked-in metadata is informational, not a contractual quote.

Recording consent

OpenTranscribe processes audio supplied by the operator. Recording and transcribing people may be subject to consent, privacy, employment, telecommunications, or data-protection laws. Operators are responsible for ensuring they have the necessary rights and consent.

Transcript content is untrusted data. OpenTranscribe never interprets it as instructions; downstream agents must preserve the same boundary.

Documentation

• Architecture
• Providers and capabilities
• Security model
• Privacy and retention
• Scaleway deployment
• Release process
• Plaud recipe
• ChatGPT + Google Drive recipe
• Contributing
• Governance
• Support
• Full product and technical specification

Contributing

Contributions are welcome. Start with the contribution guide; open a feature issue before substantial work, and report vulnerabilities only through the private process in SECURITY.md.

Independence and trademarks

OpenTranscribe is an independent open-source project maintained by its contributors. It is not affiliated with, endorsed by, or sponsored by Plaud, Microsoft, ElevenLabs, Groq, or any transcription provider.

Plaud and all provider product names are trademarks of their respective owners.

License

Apache License 2.0. See LICENSE.