PG_MCP_SERVER

What is PG_MCP_SERVER?

PG_MCP_SERVER is a general-purpose PostgreSQL MCP (Model Context Protocol) server that provides efficient schema context to large language models by pre-processing table structures. It supports PostGIS and PgVector extensions and communicates via Stdio or SSE transports.

How to use PG_MCP_SERVER?

Configure the database connection string either in main.go via RegisterConnection or by setting the SCHEMA_LOAD_DB_URL environment variable. Run with Docker (docker run -d -p 8181:8181 pg-mcp-server:latest) or directly with go run ./cmd/server/main.go after cloning and installing dependencies.

Key features of PG_MCP_SERVER

• Pre-fetches database schema to reduce token usage.
• Uses MCP Tool descriptions and Resources for implicit schema context.
• Supports PostGIS geometry types, indexes, and EPSG codes.
• Native PgVector extension support.
• Implements Stdio and SSE transports.
• Docker deployment available.

Use cases of PG_MCP_SERVER

• Provide LLMs with optimized database context without repeated schema queries.
• Query spatial data in PostGIS-enabled databases through natural language.
• Manage vector embeddings stored with PgVector via LLM agents.
• Enable secure, role-based read-only database access for MCP applications.

FAQ from PG_MCP_SERVER

Why does PG_MCP_SERVER pre-process the database schema instead of reading it on every call?

Reading the schema on each call consumes significant time and token context. Pre-processing caches table structures, columns, constraints, foreign keys, indexes, geometry types, and EPSG codes during initialization.

What database permissions does PG_MCP_SERVER require?

It recommends creating a dedicated role with SELECT on the public schema and all privileges on a temp schema. Configuring a role limits SQL injection risk and protects sensitive data.

Which PostgreSQL extensions are supported?

PostGIS and PgVector are fully supported. PgRouting support is marked as partial (⭕).

What transport protocols are available?

PG_MCP_SERVER supports Stdio and SSE transports via the go-mcp library.

How do I configure the database connection?

Set the connection string in main.go with schemaLoadConnID, err := dbService.RegisterConnection(tempCtx, "postgres://user:pass@host:port/db") or use the SCHEMA_LOAD_DB_URL environment variable in a .env file.