embark-mcp/README.md

MCP server proxy for Embark code search

# Embark MCP Server

A Model Context Protocol (MCP) server that provides a proxy interface to Embark's semantic code search capabilities. This server enables LLM applications to search through code repositories using Embark's powerful indexing and similarity search.

## Features

- **Semantic Code Search**: Search for code using natural language queries through Embark's semantic search engine
- **Dependency-Based Search**: Search for code that uses specific dependencies and libraries
- **MCP Protocol Compliance**: Fully compatible with the Model Context Protocol standard
- **JetBrains Account Authentication**: Secure authentication with Embark's API using JetBrains Account OAuth
- **Configurable Repositories**: Search across different code repositories
- **Fallback JWT Support**: Supports `GRAZIE_JWT_TOKEN` for non-interactive environments

## Installation

1. Clone the repository:
```bash
git clone <repository-url>
cd embark-mcp
```

2. Install dependencies:
```bash
npm install
```

3. Build the project:
```bash
npm run build
```

## Configuration

### Authentication

This server uses JetBrains Account OAuth for authentication by default. 

#### First-Time Authorization

The OAuth flow is triggered when you first use a search tool. To manually trigger the authorization before using it with Claude Desktop:

1. Start the server: `npx embark-mcp`
2. In another terminal, trigger a search to start the OAuth flow:
   ```bash
   echo '{"method": "tools/call", "params": {"name": "semantic_code_search", "arguments": {"text": "test"}}}' | npx embark-mcp
   ```
3. The server will automatically open a browser window to `https://account.jetbrains.com`
4. Log in with your JetBrains Account credentials
5. Review and accept the authorization request for Embark access
6. The browser will redirect to a success page showing "Authorization successful, return to the terminal"
7. Return to your terminal - the server should now be authenticated

The authorization tokens are securely saved in `~/.jbaccount` for future sessions, so you only need to do this once.

### Environment Variables

- `GRAZIE_JWT_TOKEN` (optional): JWT authentication token for Embark API. If provided, it will be used instead of the OAuth flow. This is useful for non-interactive environments.
- `JETBRAINS_AI_URL` (optional): Base URL for JetBrains AI API (defaults to `https://api.jetbrains.ai`, can be set to `https://api.stgn.jetbrains.ai/` for staging).
- `REPOSITORY_GIT_REMOTE_URL` (optional): Default repository Git remote URL to search in (can be overridden per search request)
- `REPOSITORY_ID` (optional): Alternative way to specify default repository (fallback for `REPOSITORY_GIT_REMOTE_URL`)

### Setting up Fallback Authentication (Optional)

If you need to use the server in a non-interactive environment, you can use a JWT token.

1. Obtain a JWT token from your Embark service administrator
2. Set the token as an environment variable:
```bash
export GRAZIE_JWT_TOKEN="your-jwt-token-here"
export REPOSITORY_GIT_REMOTE_URL="https://github.com/owner/repo.git"  # optional default repository
```

## Usage

### Running the Server

#### Using npx (Recommended)

You can run the server directly using `npx` without cloning the repository:

```bash
# Optional: set a default repository
export REPOSITORY_GIT_REMOTE_URL="https://github.com/owner/repo.git"

# Run the server and follow the on-screen instructions for OAuth login
npx embark-mcp
```

If you are using fallback JWT authentication:
```bash
# Set your authentication token
export GRAZIE_JWT_TOKEN="your-jwt-token-here"
export REPOSITORY_GIT_REMOTE_URL="https://github.com/owner/repo.git"  # optional

# Run the server
npx embark-mcp
```

#### Running from Source

Start the MCP server:
```bash
npm start
```

Or for development with auto-reload:
```bash
npm run dev
```

### Integrating with Claude Desktop

Add the server to your Claude Desktop configuration file:

**macOS/Linux**: `~/.config/claude/claude_desktop_config.json`
**Windows**: `%APPDATA%/Claude/claude_desktop_config.json`

#### Using npx (Recommended)

```json
{
  "mcpServers": {
    "embark-mcp": {
      "command": "npx",
      "args": ["embark-mcp"],
      "env": {
        "JETBRAINS_AI_URL": "https://api.jetbrains.ai",
        "REPOSITORY_GIT_REMOTE_URL": "https://github.com/owner/repo.git"
      }
    }
  }
}
```
**Note**: For the OAuth flow to work with Claude Desktop, you must complete the initial authorization process first. Follow the steps in the "First-Time Authorization" section above to trigger the OAuth flow and save the tokens before Claude Desktop attempts to use the server.

#### Using Local Installation

```json
{
  "mcpServers": {
    "embark-mcp": {
      "command": "node",
      "args": ["/path/to/embark-mcp/dist/index.js"],
      "env": {
        "REPOSITORY_GIT_REMOTE_URL": "https://github.com/owner/repo.git"
      }
    }
  }
}
```

### Available Tools

#### `semantic_code_search`

Search for code using Embark's semantic search engine.

**Parameters:**
- `text` (required): The text/code to search for. Use detailed, descriptive natural language queries for best results. Examples: "function that validates user email addresses and returns boolean", "error handling middleware for HTTP requests with logging", "React component that renders a modal dialog with close button".
- `repositoryGitRemoteUrl` (optional): The repository Git remote URL to search in (defaults to `REPOSITORY_GIT_REMOTE_URL` environment variable)

**Example:**
```
Search for "authentication middleware" in the codebase
```

**Response Format:**
```
Found 5 results for "authentication middleware" in repository "https://github.com/owner/repo.git":

1. File=src/middleware/auth.js, offset=120:340, similarity=0.892, type=FUNCTION
2. File=lib/security/middleware.ts, offset=45:180, similarity=0.834, type=CLASS
3. File=routes/auth.js, offset=890:1120, similarity=0.776, type=FUNCTION
...
```

#### `search_in_dependencies`

Search for code that uses specific dependencies using Embark's semantic search.

**Parameters:**
- `text` (required): The search query describing what to look for in relation to dependencies
- `dependencies` (required): Array of dependency objects with the following structure:
  - `dependency` (required): The dependency name
  - `version` (required): The dependency version

**Example:**
```
Search for code that uses React hooks with specific dependencies
```

**Dependencies Parameter Example:**
```json
[
  {"dependency": "react", "version": "18.0.0"},
  {"dependency": "react-hooks", "version": "1.0.0"}
]
```

**Response Format:**
```
Found 3 results for "React hooks usage" with dependencies [react:18.0.0, react-hooks:1.0.0] in repository "https://github.com/owner/repo.git":

1. File=src/components/UserProfile.tsx, offset=45:180, similarity=0.891, type=FUNCTION
2. File=src/hooks/useAuth.ts, offset=12:95, similarity=0.834, type=FUNCTION
3. File=src/pages/Dashboard.tsx, offset=200:350, similarity=0.776, type=FUNCTION

Timings: search: 120ms, total: 150ms
```

## API Reference

### Embark API Integration

This server integrates with Embark's REST API endpoints:

#### Semantic Code Search
- **Endpoint**: `/user/v5/indexing/search`
- **Method**: POST
- **Authentication**: Bearer token from JetBrains Account OAuth or `GRAZIE_JWT_TOKEN` via `grazie-authenticate-jwt` header
- **Request Body**:
  ```json
  {
    "text": "search query",
    "repository": "https://github.com/owner/repo.git"
  }
  ```

#### Dependencies Search
- **Endpoint**: `/search-dependencies`
- **Method**: POST
- **Authentication**: Bearer token from JetBrains Account OAuth or `GRAZIE_JWT_TOKEN` via `grazie-authenticate-jwt` header
- **Request Body**:
  ```json
  {
    "index": "ProductionIndices.CodeBlocks",
    "text": "search query",
    "dependencies": [
      {"dependency": "react", "version": "18.0.0"}
    ],
    "maxResults": 10,
    "minScore": 0.0,
    "logAllowed": false,
    "searchPipelineConfig": "SearchPipelineConfig.SearchOnly"
  }
  ```

### Response Structure

#### Semantic Code Search Response

Embark returns search results with the following structure:

```typescript
interface SearchResponse {
  searchResponse: {
    res: Array<{
      scoredText: {
        text: string;
        similarity: number;
      };
      sourcePosition: {
        relativePath: string;
        startOffset: number;
        endOffset: number;
      };
      indexItemType: string;
    }>;
  };
}
```

#### Dependencies Search Response

The dependencies search endpoint returns results with timing information:

```typescript
interface DependenciesSearchResponse {
  results: Array<{
    searchResult: {
      sourcePosition: {
        relativePath: string;
        startOffset: number;
        endOffset: number;
      };
      indexItemType: string;
      similarity: number;
    };
    content: string;
  }>;
  timings: {
    [key: string]: number; // timing in milliseconds
  };
}
```

## Development

### Building

```bash
npm run build
```

### Development Mode

```bash
npm run dev
```

### Watch Mode

```bash
npm run watch
```

## Troubleshooting

### Common Issues

1. **OAuth Error**: 
    - Ensure your browser is available to complete the login flow.
    - If behind a firewall, ensure that `https://www.jetbrains.com` and `http://localhost:62345` (or a nearby port) are accessible.
    - If the browser doesn't open automatically, copy the URL from the terminal and open it manually.
2. **Authentication Error (JWT)**: Ensure your `GRAZIE_JWT_TOKEN` is valid and not expired. This is only relevant if you are using fallback authentication.
3. **Connection Error**: Check that the `JETBRAINS_AI_URL` is correct and accessible.
4. **No Results**: Verify the repository name exists and is accessible with your token.

### Error Messages

- `Failed to get authorization code`: The OAuth flow was not completed successfully.
- `Embark API error (401)`: Invalid or expired token (either from OAuth or JWT).
- `Embark API error (404)`: Repository not found or not accessible.

## License

MIT

## Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Submit a pull request

## Support

For issues related to:
- **This MCP server**: Open an issue in this repository
- **Embark API**: Contact your Embark service administrator
- **Model Context Protocol**: See the [official MCP documentation](https://modelcontextprotocol.io/)