sqlfluff-mcp-server

An MCP server that exposes SQLFluff's linting, fixing, and parsing over the Model Context Protocol, so any MCP-aware client (Claude, other agents, IDE integrations) can lint and fix SQL directly.

This project is independent of the SQLFluff maintainers — it's a thin wrapper around the public sqlfluff Python package.

Tools

Tool	Input	Config resolution
lint_file	path on disk	walks up from the file for .sqlfluff / pyproject.toml / etc.
fix_file	path on disk (+ write flag)	same directory walk
parse_file	path on disk	same directory walk
lint_sql	raw SQL text + dialect	none — dialect supplied explicitly
fix_sql	raw SQL text + dialect	none — dialect supplied explicitly
parse_sql	raw SQL text + dialect	none — dialect supplied explicitly
list_dialects	—	lists supported dialect names

The *_file tools honor project config the same way the sqlfluff CLI does (via FluffConfig.from_path, which walks up the directory tree looking for .sqlfluff, pyproject.toml, setup.cfg, or tox.ini). The *_sql tools are for content that hasn't been written to disk (e.g. streamed from an editor buffer) and require you to pass dialect explicitly since there's no file location to resolve config from.

Requirements

• Python 3.10+
• uv (recommended) or pip

Install

git clone <this-repo-url>
cd sqlfluff-mcp-server
uv sync            # or: pip install -e ".[dev]"

Run

uv run sqlfluff-mcp-server          # or: sqlfluff-mcp-server, if installed on PATH

This starts the server over stdio, the standard transport for MCP clients that launch servers as a subprocess (Claude Desktop, Claude Code, etc.).

Registering with an MCP client

Example Claude Desktop / Claude Code config entry:

{
  "mcpServers": {
    "sqlfluff": {
      "command": "uv",
      "args": ["--directory", "/path/to/sqlfluff-mcp-server", "run", "sqlfluff-mcp-server"]
    }
  }
}

Development

uv sync --extra dev
uv run pytest
uv run ruff check .

Notes on dependencies

• mcp is pinned to <2.0.0. The SDK's 2.0 line restructured the high-level server API (no more mcp.server.fastmcp.FastMCP); this project hasn't been migrated yet.
• sqlfluff is left unpinned above 3.0.0 — SQLFluff releases fairly often and this server only depends on its stable Linter / FluffConfig API.

License

MIT — see LICENSE.