Postgres

The Postgres server was one of the original reference implementations. When the monorepo trimmed its maintained set the code moved to modelcontextprotocol/servers-archived; the @modelcontextprotocol/server-postgres package is still installable but has not received a release in over a year. Useful as a minimal, well-audited starting point — production users should evaluate a maintained fork before depending on it for anything critical. What it does: - Introspects tables, columns, indexes, and foreign keys on connect - Executes SELECT statements only, writes are rejected before the query reaches Postgres - Applies a per-statement row cap and a configurable statement_timeout - Supports a database and schema allow-list via a JSON config file - Surfaces EXPLAIN for planner-level debugging without exposing pg_stat_statements - Streams large result sets as paginated tool responses so a single query cannot flood context Example: Point it at a reporting replica with READ_ONLY=1 and an analyst agent can answer "which enterprise customers used feature X at least three times in the last 30 days" by composing JOINs across the introspected schema, with no risk of an accidental UPDATE reaching the primary. Setup: Connection via a standard postgres:// URL passed as the first argument. Create a dedicated read-only role (REVOKE INSERT/UPDATE/DELETE) and connect as that role for defence in depth, rather than trusting the server's own write-block alone. Transport: stdio. No HTTP or SSE variant. Notes: Because upstream maintenance has stopped, the soft-reliability score here is capped. Known gap: the introspection path does not surface inherited-partition parents distinctly from their children, which confuses agents reasoning about partitioning. Active forks on GitHub patch this but ship under different package names.