leonardcser/nvim-lsp-mcp

Neovim LSP MCP

A Model Context Protocol (MCP) server that provides access to linter diagnostics from a workspace via Neovim's LSP.

Tools

read-lints

Read diagnostics from the current workspace via Neovim LSP.

This tool attaches to an existing Neovim session. It prefers NVIM_LISTEN_ADDRESS if set; otherwise it will auto-discover running Neovim sockets and attach to the one whose getcwd() matches the requested workspace. It does not spawn new Neovim instances.

Parameters:

• workspace (string, required): Absolute path to the workspace. The Neovim session's cwd must equal this path.

Behavior:

• Connects to the Neovim session specified by NVIM_LISTEN_ADDRESS, or auto-discovers an appropriate session by cwd match.
• Validates that getcwd() in Neovim equals workspace. If not, returns an error.
• Collects diagnostics for loaded buffers using vim.diagnostic.get(bufnr) and returns them grouped by file as JSON text.

Installation

go build -o nvim-lsp-mcp ./cmd/server

Usage

Run the server:

./nvim-lsp-mcp

Ensure you have a Neovim instance running with LSP diagnostics in the same workspace, and either:

• Export NVIM_LISTEN_ADDRESS from that Neovim, or
• Rely on auto-discovery (the server searches typical socket locations and selects the session whose cwd equals workspace).

MCP Configuration

To use this server with Claude Desktop or other MCP clients, add it to your MCP configuration file.

{
  "mcpServers": {
    "nvim-lsp": {
      "command": "/path/to/nvim-lsp-mcp",
      "args": []
    }
  }
}

Replace /path/to/nvim-lsp-mcp with the actual path to your compiled binary.

Other MCP Clients

For other MCP clients, configure the server with:

• Command: Path to the nvim-lsp-mcp binary
• Args: Empty array []
• Transport: STDIO

Custom Cursor Rules

You can create custom rules in Cursor to make the agent proactively use the read-lints tool. Create a AGENTS.md file in your project root or config with a rule like this:

# Lint Rule

- IMPORTANT: After creating or editing ANY file, run the read-lints tool to
  check for lint errors passing the files you created/edited and address them
  proactively.
- If lint warnings/errors appear from files you did not create/edit, ask the
  user if they want you to fix those files at the end of the tasks you were
  given.
- If you fixed a lint error and recheck with the read-lints tool and get the
  same error, tell the user to reload the file in their nvim client.
- When the user asks to run lint checks or run lint tool, do not use the
  read-lints tool. However if the user asks to fix the lint errors, or fix the
  lint errors in a file, then use the read-lints tool.

This rule ensures the agent automatically checks for lint errors after making changes and proactively addresses them.

Configuration

• Set log path with NVIM_LSP_MCP_LOG (defaults near the executable)
• Logging is written to a single file; rotate externally if needed

Requirements

• Go 1.25.1+
• Neovim running with active LSP diagnostics in the target workspace
• Socket accessibility via NVIM_LISTEN_ADDRESS or auto-discovery

Troubleshooting

• "failed to attach to Neovim": ensure a Neovim instance is running and either export NVIM_LISTEN_ADDRESS or open Neovim in the same workspace so auto-discovery can match by cwd.
• "nvim cwd mismatch": open Neovim with :cd /absolute/path/to/project (or start Neovim from that directory) to align with workspace.
• Empty results: diagnostics are only returned for buffers with diagnostics; ensure your LSP is configured and diagnostics exist.

[!NOTE]

In larger codebases, the fixed 3-second wait after refreshing diagnostics (see internal/nvim/diagnostics.go) may not suffice for LSP servers to update fully, potentially missing new diagnostics in slow-loading projects.

License

MIT