mcpdap.nvim

A NeoVim plugin that exposes nvim-dap debugging functionality via the Model Context Protocol (MCP) through mcphub.nvim.

This allows any chat plugin that supports MCP to control debugging sessions, set breakpoints, step through code, and evaluate expressions.

Features

Session Management

• run - Start a new debug session with full configuration (no user interaction)
• continue - Continue execution of a paused debug session
• terminate - Terminate the current debug session
• disconnect - Disconnect from the debug adapter
• status - Get current debug session status

Breakpoint Management

• set_breakpoint_at - Set a breakpoint at a specific file and line number
• remove_breakpoint_at - Remove a specific breakpoint at file and line
• clear_breakpoints - Clear all breakpoints
• list_breakpoints - List all breakpoints and log points
• get_breakpoints - Get detailed information about all breakpoints and log points

Step Control

• step_over - Step over the current line
• step_into - Step into the current function or method
• step_out - Step out of the current function or method
• run_to - Run execution to a specific file and line number

Information & Evaluation

• evaluate - Evaluate expressions in debug context
• get_program_output - Get the output from the running/debugged program
• get_current_location - Get the current execution location in the debugger
• wait_until_paused - Wait until the debugger is paused

Resources

• dap://session - Current debug session information
• dap://stack - Current stack trace information
• dap://output - Current program output (all categories combined)
• dap://output/{category} - Program output filtered by category (stdout, stderr, console)
• dap://output/recent/{lines} - Recent program output (specify number of lines)
• mcpdap://breakpoints - List all currently set breakpoints in JSON format

Requirements

• nvim-dap - Debug Adapter Protocol client
• mcphub.nvim - MCP integration for Neovim

Installation

Using lazy.nvim

{
  "guill/mcpdap.nvim",
  dependencies = {
    "mfussenegger/nvim-dap",
    "ravitemer/mcphub.nvim"
  },
  config = function()
    -- Then setup mcpdap
    require('mcpdap').setup({})
  end
}

Manual Setup

1. Install the dependencies:

   • nvim-dap
   • mcphub.nvim

2. Add this plugin to your configuration

3. In your init.lua, after setting up mcphub:

-- Setup mcphub first
require('mcphub').setup({
  -- your mcphub configuration
})

-- Then register the DAP MCP server
require('mcpdap').setup({})

Usage

Once installed, the DAP tools will be available in any MCP-compatible chat plugin through mcphub.

Example Commands

Start debugging with full configuration:

Use the run tool to start debugging:
- type: "python"
- request: "launch" 
- name: "Debug current file"
- program: "${file}"

Start debugging a specific Python script:

Run a debug session with type "python", request "launch", name "Debug main.py", program "/path/to/main.py", and args ["-v", "--debug"]

Attach to a running process:

Start a debug session to attach to a process:
- type: "python"
- request: "attach"
- name: "Attach to server"
- host: "localhost"
- port: 5678

Continue a paused session:

Use the continue tool to resume execution

Set a breakpoint:

Set a breakpoint at line 25 in file main.py

Step through code:

Step over the current line, then step into the next function call

Evaluate expressions:

Evaluate the expression "user.name" in the current debug context

Get session info:

Show me the current debug session status

Configuration

The plugin works with your existing nvim-dap configuration. Make sure you have:

1. Debug adapters configured for your languages
2. Launch configurations set up
3. nvim-dap working properly

Example nvim-dap setup for Python:

local dap = require('dap')

-- Configure Python debug adapter
dap.adapters.python = {
  type = 'executable',
  command = 'python',
  args = { '-m', 'debugpy.adapter' },
}

-- Configure Python debug configurations
dap.configurations.python = {
  {
    type = 'python',
    request = 'launch',
    name = "Launch file",
    program = "${file}",
    pythonPath = function()
      return vim.fn.exepath('python3')
    end,
  },
}

Troubleshooting

Plugin not working

1. Ensure nvim-dap is properly installed and configured
2. Verify mcphub.nvim is set up correctly
3. Check that you're requiring mcpdap after mcphub.setup()

Debug session issues

1. Make sure you have debug adapters configured for your language
2. Verify your launch configurations are correct
3. Test nvim-dap directly first to ensure it's working

MCP tools not appearing

1. Check mcphub is running: :MCPHub
2. Verify the DAP server is connected in the mcphub UI
3. Look for error messages in :messages

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Submit a pull request

License

MIT License - see LICENSE file for details.