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MCP Integration

Coraline exposes its code intelligence capabilities via the Model Context Protocol (MCP), enabling AI assistants to understand and navigate your codebase.

What is MCP?

The Model Context Protocol is a standard for connecting AI assistants to external data sources and tools. Coraline implements MCP to expose 33 code intelligence tools that AI assistants can use.

Supported Clients

Coraline works with any MCP-compatible client:

  • Claude Desktop - Official Anthropic desktop app
  • Claude Code - CLI-based Claude integration
  • OpenCode - Multi-model terminal AI assistant (see OpenCode Integration)
  • Any other MCP-compatible client

Claude Desktop

Claude Desktop is the official Anthropic desktop application with built-in MCP support.

Configuration

Add Coraline to Claude Desktop’s MCP configuration:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json Linux: ~/.config/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "coraline": {
      "command": "/path/to/coraline",
      "args": ["serve", "--mcp", "--path", "/path/to/your/project"]
    }
  }
}

Replace /path/to/coraline with the full path to your Coraline binary:

# Find your Coraline path
which coraline

Common paths:

  • Cargo install: ~/.cargo/bin/coraline
  • macOS Homebrew: /opt/homebrew/bin/coraline
  • System install: /usr/local/bin/coraline

Multiple Projects

To work with multiple projects, add multiple servers:

{
  "mcpServers": {
    "coraline-projectA": {
      "command": "/Users/you/.cargo/bin/coraline",
      "args": ["serve", "--mcp", "--path", "/Users/you/projectA"]
    },
    "coraline-projectB": {
      "command": "/Users/you/.cargo/bin/coraline",
      "args": ["serve", "--mcp", "--path", "/Users/you/projectB"]
    }
  }
}

Restart Claude Desktop

After editing the config, restart Claude Desktop to load the new MCP server.

Verify Connection

In Claude Desktop, you should see MCP tools available. Try a prompt like:

Search for authentication functions in my codebase

Claude should use the coraline_search tool automatically.

Claude Code

Claude Code is a terminal-based CLI for Claude with MCP support.

Configuration

Create or edit .claude/mcp.json in your workspace directory:

{
  "mcpServers": {
    "coraline": {
      "command": "coraline",
      "args": ["serve", "--mcp"]
    }
  }
}

When --path is omitted, Coraline uses the current working directory as the project root.

Per-Project Setup

Each project can have its own MCP configuration:

cd your-project
mkdir -p .claude
cat > .claude/mcp.json << 'EOF'
{
  "mcpServers": {
    "coraline": {
      "command": "coraline",
      "args": ["serve", "--mcp"]
    }
  }
}
EOF

Usage

Start Claude Code in your project:

cd your-project
claude

Claude will automatically connect to Coraline and have access to all tools.

Example Prompts

Find all functions that call authenticate()
Show me the impact of changing the User class
Build context for adding a new payment method
What files are in the src/auth directory?

Environment Variables

Logging

Enable debug logging for troubleshooting:

{
  "mcpServers": {
    "coraline": {
      "command": "coraline",
      "args": ["serve", "--mcp"],
      "env": {
        "CORALINE_LOG": "debug"
      }
    }
  }
}

Logs are written to .coraline/logs/coraline.log.

Timeout Configuration

For long-running operations, increase the timeout (in milliseconds):

{
  "mcpServers": {
    "coraline": {
      "command": "coraline",
      "args": ["serve", "--mcp", "--timeout", "300000"]
    }
  }
}

Default: 120000ms (2 minutes) Maximum: 600000ms (10 minutes)

See OpenCode Integration for more timeout details.

Available Tools

Once configured, AI assistants have access to 33 tools:

Core Tools:

  • coraline_search - Find symbols by name
  • coraline_semantic_search - Natural language search (requires embeddings)
  • coraline_callers - Find what calls a symbol
  • coraline_callees - Find what a symbol calls
  • coraline_impact - Analyze change impact
  • coraline_context - Build context for a task

Advanced:

  • coraline_batch_get_nodes - Fetch multiple nodes (60-90% token savings)
  • coraline_batch_callers - Batch caller queries
  • coraline_batch_callees - Batch callee queries
  • coraline_search_by_signature - Search by type signature
  • coraline_search_by_docstring - Search docstrings
  • coraline_search_exported_symbols - Public API only

File & Config:

  • coraline_read_file - Read file contents
  • coraline_list_dir - List directory
  • coraline_get_file_nodes - Symbols in a file
  • coraline_status - Project statistics
  • coraline_sync - Incremental update
  • coraline_get_config / coraline_update_config - Configuration

Memory:

  • coraline_write_memory - Create/update memories
  • coraline_read_memory - Read memories
  • coraline_list_memories - List all memories
  • coraline_delete_memory - Delete a memory
  • coraline_edit_memory - Edit via find/replace

See MCP Tools Reference for complete documentation.

Best Practices

Initialize Before Connecting

Always initialize and index your project before connecting MCP clients:

cd your-project
coraline init -i

Keep Index Updated

Enable git hooks for automatic updates:

coraline hooks install

Or manually sync after changes:

coraline sync

Use Compact Output

All tools support output_format: "compact" for 65% token reduction:

Search for User class with compact output format

The AI assistant will use compact format automatically when instructed.

Batch Queries

For multiple lookups, ask the AI to use batch tools:

Use batch tools to get details for these 10 functions

This saves 60-90% of tokens compared to individual queries.

Project Memories

Use memories to maintain context across sessions:

Write a memory about the authentication architecture
Update the architecture_notes memory with the new JWT approach

Troubleshooting

Tools not appearing

  1. Check that Coraline is in your PATH:

    which coraline

  2. Verify the config path is correct

  3. Restart the MCP client

  4. Check logs in .coraline/logs/coraline.log

“Project not initialized”

Initialize the project first:

cd /path/to/your/project
coraline init -i

Then restart the MCP client.

Timeout errors

Increase the timeout in your MCP config:

"args": ["serve", "--mcp", "--timeout", "300000"]

Stale results

Sync the index:

coraline sync

Or force a full reindex:

coraline index --force

Permission denied

Ensure Coraline has read access to your project files and write access to .coraline/.

Advanced Configuration

Custom Project Root

Specify a different project root than the working directory:

{
  "mcpServers": {
    "coraline": {
      "command": "coraline",
      "args": ["serve", "--mcp", "--path", "/custom/project/path"]
    }
  }
}

Monorepo Setup

For monorepos, point each server to a different package:

{
  "mcpServers": {
    "coraline-frontend": {
      "command": "coraline",
      "args": ["serve", "--mcp", "--path", "/monorepo/packages/frontend"]
    },
    "coraline-backend": {
      "command": "coraline",
      "args": ["serve", "--mcp", "--path", "/monorepo/packages/backend"]
    }
  }
}

Each package needs its own .coraline/ directory.

Next Steps