sqllens 0.0.2

Natural-language SQL analytics over MCP. Connect any AI assistant to your database.

SQL Lens

Natural-language SQL analytics over MCP. Connect any MCP-aware AI assistant — Cursor, Claude Desktop, Windsurf, custom client — to a database and ask questions in plain English.

Status: Pre-alpha. APIs and config will change before 0.1.0.

What it does

A standalone MCP server that wraps a natural-language SQL agent + a vector memory store. It exposes two tools:

Tool	What it does
query_database(question)	Translates the question to SQL, runs it, returns a Markdown table.
list_data_sources()	Describes the configured database (name, dialect, read-only state).

One database per running instance. Read-only by default — generated SQL is parsed with sqlglot and rejected if it isn't a SELECT. ChromaDB stores per-question memory locally so the agent learns from corrections.

Quick start (60 seconds, with the bundled SQLite Chinook DB)

git clone https://github.com/The01Geek/sqllens.git
cd sqllens
pip install -e ".[all]"
export SQLLENS_LLM__API_KEY=sk-ant-...
sqllens serve -c examples/sqlite-demo/sqllens.toml

The server is now live on stdio. Point an MCP client at the process and ask: "How many albums did AC/DC release?"

Prefer HTTP? Edit the config:

[server]
transport = "http"
host = "127.0.0.1"
port = 8765

sqllens serve starts uvicorn at http://127.0.0.1:8765/mcp/. Both /mcp and /mcp/ work; / redirects to the canonical form.

Configure

sqllens init writes a starter sqllens.toml. Every field can be overridden by environment variables — nested fields use double-underscore:

export SQLLENS_DATABASE__URL="postgresql://user:pw@host/db"
export SQLLENS_LLM__API_KEY="sk-ant-..."
export SQLLENS_AUTH__MODE="bearer"
export SQLLENS_AUTH__BEARER_TOKEN="abc-123"

Env vars beat TOML — the convention containerized deploys expect.

Database URLs

Dialect	Example
SQLite	sqlite:///./demo.db
Postgres	postgresql://user:pw@host:5432/dbname
MySQL	mysql+pymysql://user:pw@host:3306/dbname

Auth modes

Mode	When to use
none	Loopback only. The default for sqllens init.
bearer	Single shared token. Set auth.bearer_token in TOML or SQLLENS_AUTH__BEARER_TOKEN in env.
jwt	Scaffolded — not implemented yet. The verifier interface is locked; the implementation lands in a follow-up. Don't deploy with this mode.

Wire up an IDE

Drop one of these into the appropriate config file:

• Cursor (~/.cursor/mcp.json) — see examples/mcp-clients/cursor.json
• Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json on macOS) — see examples/mcp-clients/claude_desktop.json
• Windsurf — see examples/mcp-clients/windsurf.json
• stdio variant (no HTTP server, IDE launches the process) — see examples/mcp-clients/stdio-cursor.json

For interactive testing, use the official MCP Inspector:

npx @modelcontextprotocol/inspector

Set transport to Streamable HTTP, URL to http://localhost:8765/mcp/, add an Authorization: Bearer … header if you've enabled bearer auth, click Connect.

Local development

git clone https://github.com/The01Geek/sqllens.git
cd sqllens
pip install -e ".[dev,all]"
ruff check .
pytest -q

The integration test suite spins up a real uvicorn server and exercises the full Streamable HTTP wire protocol end-to-end. No real LLM calls are made — query_database is gated behind a separate, opt-in test that requires a live Anthropic key.

Project structure

sqllens/
├── src/sqllens/
│   ├── cli.py              # Typer entrypoint: version | init | validate | serve
│   ├── config.py           # pydantic-settings: TOML + SQLLENS_ env vars
│   ├── server.py           # Dispatch to stdio or HTTP transport
│   ├── transport/http.py   # Streamable HTTP + auth middleware + path normalizer
│   ├── tools/              # MCP tool implementations
│   ├── agent/              # NL-to-SQL agent + framework
│   ├── connectors/         # Reserved for SQLAlchemy-backed adapters (Phase 3)
│   ├── auth/               # none | bearer | jwt
│   └── safety/             # Read-only SQL guard
├── examples/
│   ├── sqlite-demo/        # Bundled Chinook DB + working config
│   └── mcp-clients/        # Drop-in config snippets per IDE
└── tests/
    ├── unit/               # Config, auth, safety
    └── integration/        # Live HTTP transport with mcp SDK client

Install

Three install paths, all produced by the same release pipeline:

Path	Command	Use when
PyPI	pip install sqllens[all] then sqllens serve	You're a Python user or running on a server.
Docker	docker run -p 8765:8765 -e SQLLENS_LLM__API_KEY=… -e SQLLENS_DATABASE__URL=… ghcr.io/the01geek/sqllens:latest	You don't want a Python install on the host. Multi-arch (amd64 + arm64), signed with cosign, SBOM attached.
MCPB	Drag the .mcpb for your platform onto Claude Desktop.	You only use Claude Desktop and want a one-click install. See mcpb/README.md.

Roadmap

• Phase 1 — Spike: agent lifted, scaffold in place, SQLite Chinook demo runs locally.
• Phase 2 — Auth (none + bearer), SQL safety guard, Streamable HTTP transport, integration tests.
• Phase 3 — Distribution: PyPI workflow, multi-arch Docker image, MCPB bundle, real-DB connector tests.
• Phase 4 — JWT verifier (JWKS + shared-secret), permission scopes, integration with Guidoo.

Contributing

Open from day 1. See CONTRIBUTING.md. Bug reports and feature requests via the issue templates.

License

Apache 2.0. See NOTICE for copyright and LICENSES/ for third-party attributions.