mcp-sqlite-explorer

A Model Context Protocol (MCP) server that safely exposes a local SQLite database to Claude and any other MCP client. Point Claude Desktop (or Claude Code) at a .db file and ask questions about your data in plain English — Claude discovers the schema and runs read-only queries through this server.

Built with the official @modelcontextprotocol/server TypeScript SDK (v2).

What it exposes

Safety — read-only by design

Three layers stop any write reaching your database:

1. The connection is opened read-only (better-sqlite3 { readonly: true }) — writes fail at the SQLite level.

2. A textual guard rejects anything that isn't a single SELECT / WITH … SELECT (blocks INSERT/UPDATE/DELETE/DROP/PRAGMA, multiple statements, and writes smuggled into a CTE).

3. Each prepared statement is checked with better-sqlite3's statement.readonly before it runs.

Results are capped (default 100 rows, max 1000) so a huge table can't flood the context.

Related MCP server: mcp-sqlite

Requirements

• Node.js 20+

Setup

npm install
npm run seed     # creates data/sample.db (customers, products, orders, order_items)
npm run build    # compile to dist/

Use it with Claude Desktop

Add this to your claude_desktop_config.json (use absolute paths):

{
  "mcpServers": {
    "sqlite-explorer": {
      "command": "node",
      "args": [
        "/absolute/path/to/mcp-sqlite-explorer/dist/index.js",
        "/absolute/path/to/your-database.db"
      ]
    }
  }
}

Restart Claude Desktop, then ask things like "What tables are in the database?" or "Which product category has the most orders?" — Claude will call list_tables, describe_table and query as needed.

With Claude Code:

claude mcp add sqlite-explorer -- node /absolute/path/to/dist/index.js /absolute/path/to/your.db

The database path can also be given via the MCP_SQLITE_DB environment variable; it defaults to data/sample.db.

Quick check (no client needed)

You can drive the server over stdio directly to confirm it works:

printf '%s\n' \
  '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"c","version":"1"}}}' \
  '{"jsonrpc":"2.0","method":"notifications/initialized"}' \
  '{"jsonrpc":"2.0","id":2,"method":"tools/list"}' \
  | node dist/index.js data/sample.db

Scripts

npm run dev       # run from source with tsx
npm run seed      # (re)create the sample database
npm run build     # compile to dist/
npm start         # run the compiled server
npm run typecheck # tsc --noEmit
npm test          # vitest

Project structure

src/
  sql-safety.ts   Pure read-only query guard + identifier check
  db.ts           Read-only SQLite wrapper (list/describe/query/schema)
  server.ts       MCP server: tools, resource, prompt
  index.ts        stdio entry point (logs to stderr only)
  seed.ts         Builds the sample database

stdio note: the MCP stdio transport uses stdout for the JSON-RPC protocol, so the server logs only to stderr — writing to stdout would corrupt the stream.

Tests

npm test

The suite covers the read-only guard (write statements, multi-statement, CTE-smuggled writes, comment handling) and the database wrapper (listing, describing, querying, row-limit truncation, and write rejection) against an in-memory database.

License

Released under the MIT License.