AssemblyAI MCP Server

A Model Context Protocol (MCP) server that provides access to AssemblyAI's transcription services. This server enables AI assistants to transcribe audio files and manage transcription jobs through a standardized interface.

Features

- Audio transcription from URLs and local files
- Asynchronous job submission for large files
- Transcript retrieval and status checking
- Resource access to transcript data
- Type-safe implementation with Zod validation
- Error handling and graceful shutdown

Installation

1. Clone or create this project directory
2. Install dependencies:
``bash
npm install
`
3. Set up your AssemblyAI API key (see Configuration section)
4. Build the TypeScript code:
`bash
npm run build
`

Configuration

You need an AssemblyAI API key to use this server. Get one from AssemblyAI.

Set the environment variable:
`bash
export ASSEMBLYAI_API_KEY="your-api-key-here"
`

Or create a .env file:
`
ASSEMBLYAI_API_KEY=your-api-key-here
`

Usage

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Start the MCP server:
`bash
npm start
`

For development with auto-rebuild:
`bash
npm run watch
`

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The server provides the following tools:

#### transcribe_url
Transcribe audio from a remote URL and wait for completion.

Parameters:
- audioUrl (string, required): URL of the audio file
- options (object, optional): Transcription options
- speaker_labels (boolean): Enable speaker diarization
- language_code (string): Specify language (e.g., "en")
- punctuate (boolean): Add punctuation
- format_text (boolean): Format text for readability

Example:
`json
{
"audioUrl": "https://example.com/audio.mp3",
"options": {
"speaker_labels": true,
"punctuate": true
}
}
`

#### transcribe_file
Transcribe audio from a local file path and wait for completion.

Parameters:
- filePath (string, required): Local path to the audio file
- options (object, optional): Same as transcribe_url

Example:
`json
{
"filePath": "/path/to/audio.wav",
"options": {
"language_code": "en"
}
}
`

#### submit_transcription
Submit audio for transcription without waiting for completion. Returns immediately with a job ID.

Parameters:
- audio (string, required): URL or local file path
- options (object, optional): Same transcription options

Example:
`json
{
"audio": "https://example.com/large-audio.mp3",
"options": {
"speaker_labels": true
}
}
`

#### get_transcript
Retrieve the status and results of a transcription job.

Parameters:
- transcriptId (string, required): The transcript ID returned from previous calls

Example:
`json
{
"transcriptId": "1234567890"
}
`

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#### transcript://{id}
Access transcript data directly by ID. Provides structured JSON with all transcript information.

Example URI: transcript://1234567890

Returns:
`json
{
"id": "1234567890",
"status": "completed",
"text": "Hello, this is a test transcription...",
"confidence": 0.95,
"words": [...],
"utterances": [...],
"created": "2024-01-01T00:00:00Z",
"completed": "2024-01-01T00:01:30Z"
}
`

Integration Examples

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Add to your claude_desktop_config.json:

`json
{
"mcpServers": {
"assemblyai": {
"command": "node",
"args": ["/path/to/assemblyai-mcp-server/dist/index.js"],
"env": {
"ASSEMBLYAI_API_KEY": "your-api-key-here"
}
}
}
}
`

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The server uses stdio transport, so it's compatible with any MCP client that supports this transport method.

Workflow Examples

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1. Use transcribe_url or transcribe_file for immediate results
2. The tool waits for completion and returns the full transcript

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1. Use submit_transcription for large files
2. Use get_transcript to check status and retrieve results
3. Use the transcript:// resource for structured data access

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`json
{
"audioUrl": "https://example.com/meeting.mp3",
"options": {
"speaker_labels": true,
"punctuate": true,
"format_text": true
}
}
`

Error Handling

The server provides detailed error messages for common issues:

- Missing API key: Server won't start without ASSEMBLYAI_API_KEY
- Invalid audio URLs: Clear error messages for inaccessible files
- File not found: Helpful messages for local file issues
- API errors: AssemblyAI error messages passed through
- Invalid transcript IDs: Clear feedback for non-existent transcripts

Development

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`bash
npm run build
`

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`bash
npm run dev
`

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`bash
npm run watch
``

Requirements

- Node.js 18.0.0 or higher
- AssemblyAI API key
- MCP-compatible client

License

MIT License

Support

For AssemblyAI API issues, visit AssemblyAI Documentation.
For MCP protocol questions, see Model Context Protocol.