sql-mcp

A Model Context Protocol server that lets AI agents read your SQL Server, PostgreSQL, MySQL and Oracle databases, and nothing more. Every query is checked, run in a transaction that is rolled back, and refused outright if the login could write.

Documentation: fuseraft.ai/sql-mcp

• Read-only, three times over. Each query must be a single SELECT, checked with the database's own rules for quotes and comments. It runs in a transaction that is always rolled back, read-only where the database supports it. And a database whose login could write is refused altogether.
• Schema context for agents. Each database's provider, so agents write the right dialect; foreign keys in both directions, table and column comments, and estimated row counts.
• Results that fit in a context. Compact rows, capped by count and size, with a note on how to narrow or page a query that was cut off. explain_query shows the plan without running anything.
• Every call attributed. Each agent has its own bearer token, and every call is logged under its name, refusals included.
• Runs where you need it. stdio for a client that launches it, or Streamable HTTP as a shared service in Docker, under systemd or as a Windows Service.

Install

You need the .NET 10 SDK.

git clone https://github.com/fuseraft/sql-mcp.git && cd sql-mcp
dotnet publish -p:PublishProfile=linux-x64   # or win-x64; self-contained, in publish/
docker build -t sql-mcp .                    # or as an image

See Install.

Configure

Point it at a database with a login that can only read:

{
  "Databases": [
    {
      "Name": "prod",
      "Provider": "Postgres",
      "ConnectionString": "Host=db.example.com;Database=myapp;Username=agent;Password={password};",
      "PasswordEnvVar": "DB_PROD_PASSWORD"
    }
  ]
}

Read-only logins shows how to create one for each database, and the configuration reference lists every setting.

Connect

claude mcp add sql -- /opt/sql-mcp/sql-mcp --stdio                                     # stdio
claude mcp add --transport http sql http://localhost:8080/mcp \
  --header "Authorization: Bearer $SQL_MCP_TOKEN"                                     # HTTP

Agents get five tools: list_databases, list_tables, describe_table, explain_query and query_database. See Connect a client for anchor, fuseraft and tokens.

Learn more

Quickstart · How queries stay read-only · Working with agents · Deployment · Logging · Tools · HTTP

Develop

dotnet test runs the tests. The integration tests run against each database whose SQLMCP_TEST_* connection string is set; Development shows how to start all four in containers. The docs site in docs/ is built with Starlight: npm install && npm run dev there to preview, and pushes to master deploy it.

License

MIT