@bossforce.ai/mcp-postgres

MCP server for PostgreSQL, built on the pg driver. Read-only by default — a good fit for reporting and data lookups.

Credentials

| Env | How to obtain | | ---------------------------- | --------------------------------------------------------------------------- | | POSTGRES_CONNECTION_STRING | postgres://user:password@host:port/database for your database. | | POSTGRES_ALLOW_WRITES | Optional. Set to true to permit writes; omit for read-only (recommended). |

The connection string is read lazily, so the server boots and answers tools/list without it; calls fail with an auth error until it is set. For defence in depth, point it at a read-only database role when writes aren't needed.

Tools

| Tool | Arguments | Returns | | ---------------- | -------------------------- | ----------------------------- | | query | sql, params? | { rows, row_count, fields } | | list_tables | schema? (default public) | { tables: [...] } | | describe_table | table, schema? | { columns: [...] } |

Safety

By default every statement runs inside a BEGIN READ ONLY transaction, so any INSERT/UPDATE/DELETE/DDL fails at the database (SQLSTATE 25006). Set POSTGRES_ALLOW_WRITES=true to allow writes. Always pass user-supplied values through params ($1, $2, …) rather than concatenating them into the SQL.

Develop

pnpm --filter @bossforce.ai/mcp-postgres build
pnpm --filter @bossforce.ai/mcp-postgres test

Tests inject a fake query implementation, so they run without a real database. Regenerate the tools/list snapshot after an intentional signature change:

UPDATE_SNAPSHOTS=1 pnpm --filter @bossforce.ai/mcp-postgres test