MCP Servers

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Claude integrates with Model Context Protocol (MCP) servers to extend Claude Code's capabilities with external tools and services.

📋 Quick Reference: See the MCP Cheatsheet for a concise reference of configuration options.

What is MCP?

Model Context Protocol (MCP) is an open standard that enables secure, controlled interactions between AI assistants and external systems. MCP servers provide tools that Claude Code can use to interact with databases, APIs, and other services.

For complete documentation, see the official Claude Code MCP guide.

Tidewave for Phoenix Projects

Claude automatically configures Tidewave for Phoenix projects. Tidewave is an MCP server that provides Phoenix-specific development tools.

Automatic Setup

When you run mix claude.install in a Phoenix project, Claude automatically:

  1. Detects Phoenix is installed
  2. Adds Tidewave to your .claude.exs configuration
  3. Generates .mcp.json with the proper server configuration
  4. Enables the MCP server in Claude Code

Manual Configuration

You can also manually configure Tidewave or other MCP servers in .claude.exs:

%{
  mcp_servers: [:tidewave]
}

Or with custom port configuration:

%{
  mcp_servers: [
    {:tidewave, [port: 5000]}
  ]
}

To disable a server without removing it:

%{
  mcp_servers: [
    {:tidewave, [enabled?: false]}
  ]
}

After updating .claude.exs, run mix claude.install to sync the configuration to .mcp.json.

How MCP Servers Work with Claude

  1. Configuration: MCP servers are defined in .mcp.json (generated from .claude.exs)
  2. Startup: Claude Code starts configured MCP servers when you begin a session
  3. Tool Access: MCP server tools appear as mcp__<server>__<tool> in Claude Code
  4. Usage: Claude can use these tools just like built-in tools

Available MCP Servers

Currently, Claude supports:

  • Tidewave - Phoenix development tools (auto-configured for Phoenix projects)

Request Additional MCP Servers

Want support for additional MCP servers? We'd love to hear from you!

Request a new MCP server →

Troubleshooting

MCP server not starting?

  • Check .mcp.json exists after running mix claude.install
  • Verify the server binary is installed (e.g., tidewave for Phoenix)
  • Check Claude Code logs for startup errors

Tools not appearing?

  • Restart your Claude Code session
  • Verify the server is enabled in .claude.exs
  • Check that .mcp.json contains the server configuration

Need help?

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