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This guide walks through connecting PostgreSQL to Claude Code using QueryBear’s managed MCP server. End result: your terminal Claude session can read your Postgres database safely — no write access, no sensitive columns exposed, every query logged.

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What you’ll need

  • A QueryBear account (sign up free)
  • A PostgreSQL database (any version 12+)
  • Claude Code installed (npm i -g @anthropic-ai/claude-code or via your preferred installer)

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Step 1: Create a read-only PostgreSQL role

Run this as a Postgres superuser. It creates a querybear role that can only SELECT: 
CREATE ROLE querybear LOGIN PASSWORD 'choose-a-strong-one';
GRANT CONNECT ON DATABASE your_db TO querybear;
GRANT USAGE ON SCHEMA public TO querybear;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO querybear;
ALTER DEFAULT PRIVILEGES IN SCHEMA public
  GRANT SELECT ON TABLES TO querybear;
QueryBear’s gateway is already read-only — this role is belt-and-suspenders.

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Step 2: Add the connection to QueryBear

In the QueryBear dashboard → Connections → New connection → PostgreSQL:
  • Host — e.g. db.example.com or your RDS endpoint
  • Port — 5432
  • Database — your DB name
  • User — querybear
  • Password — from Step 1
  • SSL mode — require
QueryBear fetches your schema. Use the Access tab to allow-list specific tables and block sensitive columns (password_hash, email, etc.).

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Step 3: Add QueryBear to Claude Code

One command: 
claude mcp add --transport http querybear https://mcp.querybear.com/mcp
That’s it. Restart claude if you had a session open.

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Step 4: Authorize and verify

Start a Claude Code session: 
claude
The first tool call from Claude opens a browser for OAuth — approve, and Claude is linked to your QueryBear account. To verify, ask:
“What QueryBear tools do you have, and what connections are available?”
You should see list_connections, get_schema, run_query, and your Postgres connection listed.

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Try it

“In production Postgres, how many users signed up in the last 7 days, broken down by signup source?”
Claude calls get_schema to find the relevant tables, writes the SQL, calls run_query, and returns the result.

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Postgres + Claude Code gotchas

  • CTE writes are blocked. Postgres allows WITH x AS (DELETE ...) SELECT * FROM x. QueryBear’s parser rejects this — if Claude generates such a query, it’ll see a clear error.
  • Connection pooling-mode Postgres (PgBouncer transaction mode) is fine for read queries. No special config needed.
  • PgVector works transparently. Operators like <->, <=>, <#> are allowed.
  • Materialized views and views appear in get_schema and are queryable.
  • Schemas other than public need an additional GRANT USAGE ON SCHEMA <name> for the querybear role.