MCP: golars as a tool for your LLM host

golars-mcp is a Model Context Protocol server that exposes a read-only subset of golars as tools any MCP host can invoke.

golars-mcp is a Model Context Protocol server that exposes a read-only subset of golars as tools an LLM host can invoke. Works with Claude Desktop, Cursor, Windsurf, and any other MCP-aware client.

Install

go install github.com/Gaurav-Gosain/golars/cmd/golars-mcp@latest

The binary lives in $GOBIN (or $HOME/go/bin by default).

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (or %APPDATA%\Claude\claude_desktop_config.json on Windows; the Linux equivalent lives under ~/.config/Claude/) and add a mcpServers entry:

{
  "mcpServers": {
    "golars": {
      "command": "/absolute/path/to/golars-mcp"
    }
  }
}

Restart the Claude Desktop app. You should see a hammer icon in the conversation pane letting you enable the golars server.

Configure Cursor / Windsurf

Both editors read the same JSON format. Add the same snippet to your workspace MCP config (~/.cursor/mcp.json for Cursor). No restart needed in Cursor; the server picks up automatically.

Available tools

Tool	What it does
`schema`	Return column names + dtypes for a data file
`head`	Return the first N rows (CSV/Parquet/Arrow/JSON/NDJSON)
`describe`	Return describe()-style summary stats
`sql`	Run a SQL query against one or more files
`row_count`	Cheap "how many rows × cols" probe
`null_counts`	Per-column null counts

Every tool returns both a plain-text fallback (for hosts that only render text) and a structuredContent payload with columns + rows arrays so richer UIs can render a table.

Example session

After configuring the server, ask your LLM host something like:

"What's the schema of ~/data/trades.csv? If any column has more than 10% nulls, summarise it with describe."

The host picks up the tool catalogue from tools/list, calls schema then null_counts then describe, and the model answers using the structured results.

Protocol notes

Protocol version: 2025-06-18. We only implement the tools capability; resources and prompts are not served (yet).
Transport: stdio JSON-RPC 2.0, one object per line.
No authentication: golars-mcp reads files the user running the host process has read access to.

Security

The MCP server is read-only. It cannot write files, start subprocesses, or reach the network. The tools only accept a path string and execute a query against its contents; SQL is compiled to a lazy plan with a whitelist of operators (no arbitrary expressions or DDL). That said, it will read any file the caller names : don't point a host LLM at secrets.

Extending

cmd/golars-mcp/tools.go registers tools into a flat slice. Add a new Tool{Name, Description, InputSchema, Run} entry and the server picks it up. Keep tools pure (no state outside the local session) so concurrent calls are safe.