One "host all all 0.0.0.0/0 trust" line in pg_hba.conf, or POSTGRES_HOST_AUTH_METHOD=trust in Docker, lets anyone who reaches the port log in as the superuser with no password. This skill finds that and nine other PostgreSQL configuration mistakes before your server goes live, and tells you how to fix each one.

Your agent runs a scanner on pg_hba.conf, postgresql.conf, postgresql.auto.conf and Docker Compose, Dockerfile and .env files that mention postgres. It reads pg_hba.conf lines the way PostgreSQL does (types, CIDR or netmask addresses, methods, quotes, comments) and settings where the last value wins. It never connects to PostgreSQL. It returns BLOCK, REVIEW, or NOT FLAGGED, with the file, line, reason, and a safer approach.

What it checks

BLOCK (fix before shipping)

• G01: trust logins from the network, or POSTGRES_HOST_AUTH_METHOD=trust

• G02: cleartext password logins without SSL

• G03: fsync or full_page_writes off (corruption after a crash)

REVIEW (check before release)

• G11: trust on local socket and 127.0.0.1 lines

• G12: rules for every address (0.0.0.0/0, ::/0, all)

• G13: listen_addresses open with ssl off

• G14: MD5 passwords

• G15: log_statement that writes passwords to the logs

• G16: TLS 1.0 or 1.1 allowed

• G17: the postgres superuser allowed from the network

What's included

• The scanner (Python 3.9+, standard library only)

• A rules guide with the reason and safer approach for each rule

• Risky and safe example configs (pg_hba.conf, postgresql.conf, docker-compose.yml), and the real report the scanner produces on the risky ones

Limits

It reads each file as written: include files, ALTER SYSTEM settings on a running server, firewalls and managed services (RDS, Cloud SQL, Supabase) are not seen. NOT FLAGGED is not a guarantee.

Contents

One ZIP file with 11 files: SKILL.md, the scanner in scripts/ (2 Python files), references/rules.md (every rule with its reason and safer approach), and examples/ (6 example files plus report.md, the real scanner output on the risky example).

How to use: This is an agent skill: a folder with a SKILL.md file and Python scripts that an AI coding agent such as Claude Code, Cursor, or Codex CLI can run. Unzip it into your agent's skills folder (for Claude Code: ~/.claude/skills/), then ask your agent to check your project. The scripts also run on their own with Python 3.9 or newer, with nothing to install. They read your files only: no network access, and nothing is sent anywhere.