Bruno API MCP Server

A Model Context Protocol (MCP) server that exposes Bruno API collections as MCP tools. This server allows you to interact with your Bruno API collections through the MCP protocol, making your API collections accessible to AI agents and other MCP clients.

Why This Matters: Source Code and Data Working Together

When developers need to integrate APIs, they typically face three core challenges:

1. Debugging across system boundaries: Diagnosing issues across separate code and data environments requires constant context switching, making troubleshooting inefficient.

2. Creating custom tooling: Each third-party API integration requires building and maintaining custom tooling, causing development overhead and technical debt.

3. Building service UIs: Developing user interfaces for every backend service adds significant complexity and maintenance costs.

This server solves these precise problems by collocating your source code with your data. It transforms Bruno API collections into Model Context Protocol tools, enabling you to:

• Debug across previously separate environments with complete context

• Turn any API into an agent-ready tool without additional custom development

• Build headless services that can be controlled through AI interfaces

For development teams that need to accelerate API integration while reducing maintenance overhead, this approach fundamentally changes what's possible - making previously complex integrations straightforward and accessible.

Related MCP server: Scenario Word

Features

• Automatic conversion of Bruno API collections to MCP tools

• Environment management for different API configurations

• HTTP with SSE transport

• Cross-origin support

• Built-in tools for API collection management

Usage

1. Install dependencies:

   npm install

2. Start the server with your Bruno API collection:

   node --loader ts-node/esm src/index.ts --bruno-path /path/to/bruno/collection [--environment env_name] [--include-tools tool1,tool2,tool3] [--exclude-tools tool4,tool5]

   Options:

   • --bruno-path or -b: Path to your Bruno API collection directory (required)

   • --environment or -e: Name of the environment to use (optional)

   • --include-tools: Comma-separated list of tool names to include, filtering out all others (optional)

   • --exclude-tools: Comma-separated list of tool names to exclude (optional)

   Both formats are supported for the tool filtering options:

   --include-tools tool1,tool2,tool3    # Space-separated format
   --include-tools=tool1,tool2,tool3    # Equals-sign format

3. Connect from clients:

   • Local connection: http://localhost:8000/sse

   • From Windows to WSL: http://<WSL_IP>:8000/sse

   • Get your WSL IP with: hostname -I | awk '{print $1}'

Predefined Scripts

The repository includes several predefined npm scripts for common use cases:

# Start the server with default settings
npm start

# Start with CFI API path
npm run start:cfi

# Start with local environment
npm run start:local

# Start with only specific tools included
npm run start:include-tools

# Start with specific tools excluded
npm run start:exclude-tools

Development

Running Tests

Run all tests:

npm test

Run specific test file:

npm test test/bruno-parser-auth.test.ts

Debugging

The server uses the debug library for detailed logging. You can enable different debug namespaces by setting the DEBUG environment variable:

# Debug everything
DEBUG=* npm start

# Debug specific components
DEBUG=bruno-parser npm start    # Debug Bruno parser operations
DEBUG=bruno-request npm start   # Debug request execution
DEBUG=bruno-tools npm start     # Debug tool creation and registration

# Debug multiple specific components
DEBUG=bruno-parser,bruno-request npm start

# On Windows CMD:
set DEBUG=bruno-parser,bruno-request && npm start

# On Windows PowerShell:
$env:DEBUG='bruno-parser,bruno-request'; npm start

Available debug namespaces:

• bruno-parser: Bruno API collection parsing and environment handling

• bruno-request: Request execution and response handling

• bruno-tools: Tool creation and registration with MCP server

Tools

List Environments

Lists all available environments in your Bruno API collection:

• No parameters required

• Returns:

  • List of available environments

  • Currently active environment

Echo

Echoes back a message you send (useful for testing):

• Parameter: message (string)

Bruno API Collection Structure

Your Bruno API collection should follow the standard Bruno structure:

collection/
├── collection.bru       # Collection settings
├── environments/       # Environment configurations
│   ├── local.bru
│   └── remote.bru
└── requests/          # API requests
    ├── request1.bru
    └── request2.bru

Each request in your collection will be automatically converted into an MCP tool, making it available for use through the MCP protocol.

Using Custom Parameters with Tools

When calling tools generated from your Bruno API collection, you can customize the request by providing:

Environment Override

You can specify a different environment for a specific request:

{
  "environment": "us-dev"
}

This will use the variables from the specified environment instead of the default one.

Variable Replacements

You can override specific variables for a single request:

{
  "variables": {
    "dealId": "abc123",
    "customerId": "xyz789",
    "apiKey": "your-api-key"
  }
}

These variables will be substituted in the URL, headers, and request body. For example, if your request URL is:

{{baseUrl}}/api/deal/{{dealId}}

And you provide { "variables": { "dealId": "abc123" } }, the actual URL used will be:

https://api.example.com/api/deal/abc123

Query Parameters

You can add or override query parameters directly:

{
  "query": {
    "limit": "10",
    "offset": "20",
    "search": "keyword"
  }
}

This will add these query parameters to the URL regardless of whether they are defined in the original request. For example, if your request URL is:

{{baseUrl}}/api/deals

And you provide { "query": { "limit": "10", "search": "keyword" } }, the actual URL used will be:

https://api.example.com/api/deals?limit=10&search=keyword

This approach is cleaner and more explicit than using variables to override query parameters.

Custom Body Parameters

You can also provide custom parameters in the request body:

{
  "body": {
    "name": "John Doe",
    "email": "john@example.com"
  }
}

Complete Example

Here's a complete example combining all four types of customization:

{
  "environment": "staging",
  "variables": {
    "dealId": "abc123",
    "apiKey": "test-key-staging"
  },
  "query": {
    "limit": "5",
    "sort": "created_at"
  },
  "body": {
    "status": "approved",
    "amount": 5000
  }
}

License

MIT