Postgres

Skill chenwei791129/agent-skills/skills/postgres

My agent skills

Install

npx -y skills add chenwei791129/agent-skills --skill postgres

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What its author says it does

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Execute read-only SQL queries against multiple PostgreSQL databases. Use when: (1) querying PostgreSQL databases, (2) exploring database schemas/tables, (3) running SELECT queries for data analysis, (4) checking database contents. Supports multiple database connections with descriptions for intelligent auto-selection. Blocks all write operations (INSERT, UPDATE, DELETE, DROP, etc.) for safety.

SKILL.md

3.7 KB, 791 tokens by cl100k_base, as published. Nobody here has run it

PostgreSQL Read-Only Query Skill

Execute safe, read-only queries against configured PostgreSQL databases.

Requirements

Python 3.8+
psycopg2-binary: pip install -r requirements.txt

Setup

Create connections.json in the skill directory or ~/.config/claude/postgres-connections.json.

Security: Set file permissions to 600 since it contains credentials:

chmod 600 connections.json

{
  "databases": [
    {
      "name": "production",
      "description": "Main app database - users, orders, transactions",
      "host": "db.example.com",
      "port": 5432,
      "database": "app_prod",
      "user": "readonly_user",
      "password": "your-password",
      "sslmode": "require"
    }
  ]
}

Config Fields

Field	Required	Description
name	Yes	Identifier for the database (case-insensitive)
description	Yes	What data this database contains (used for auto-selection)
host	Yes	Database hostname
port	No	Port number (default: 5432)
database	Yes	Database name
user	Yes	Username
password	Yes	Password
sslmode	No	SSL mode: disable, allow, prefer (default), require, verify-ca, verify-full

Usage

List configured databases

python3 scripts/query.py --list

Query a database

python3 scripts/query.py --db production --query "SELECT * FROM users LIMIT 10"

List tables

python3 scripts/query.py --db production --tables

Show schema

python3 scripts/query.py --db production --schema

Limit results

python3 scripts/query.py --db production --query "SELECT * FROM orders" --limit 100

Database Selection

Match user intent to database description:

User asks about	Look for description containing
users, accounts	users, accounts, customers
orders, sales	orders, transactions, sales
analytics, metrics	analytics, metrics, reports
logs, events	logs, events, audit

If unclear, run --list and ask user which database.

Safety Features

Read-only session: Connection uses PostgreSQL readonly=True mode (primary protection)
Query validation: Only SELECT, SHOW, EXPLAIN, WITH queries allowed
Single statement: Multiple statements per query rejected
SSL support: Configurable SSL mode for encrypted connections
Query timeout: 30-second statement timeout enforced
Memory protection: Max 10,000 rows per query to prevent OOM
Column width cap: 100 char max per column for readable output
Credential sanitization: Error messages don't leak passwords

Troubleshooting

Error	Solution
Config not found	Create `connections.json` in skill directory
Authentication failed	Check username/password in config
Connection timeout	Verify host/port, check firewall/VPN
SSL error	Try `"sslmode": "disable"` for local databases
Permission warning	Run `chmod 600 connections.json`

Exit Codes

0: Success
1: Error (config missing, auth failed, invalid query, database error)

Workflow

Run --list to show available databases
Match user intent to database description
Run --tables or --schema to explore structure
Execute query with appropriate LIMIT

What ships with it: 6 files

12.4 KB alongside SKILL.md, 1 of them executable

.claude-plugin/

plugin.json171 B

scripts/

query.pyruns9.2 KB

Gives 0 of the 12 instructions most databases sql skills give in 791 tokens

Counted across 589 of the 662 authors here whose files we hold, read 2026-08-07

Use parameterized queriesin 37 of 589, across 34 files
Use timestamptz for timestampsin 30 of 589, across 14 files
Index foreign keysin 29 of 589, across 18 files
Create indexes concurrentlyin 29 of 589, across 24 files
Use numeric type for moneyin 25 of 589, across 8 files
Use cursor pagination instead of offsetin 24 of 589, across 17 files
Select only required columnsin 24 of 589, across 20 files
Add indexes manually on foreign key columnsin 22 of 589, across 12 files
Normalize to third normal formin 19 of 589, across 10 files
Configure connection poolingin 19 of 589, across 17 files
Put equality columns before range columns in indexesin 18 of 589, across 10 files
Read individual rule files for detailed explanationsin 18 of 589, across 4 files

Said here and by no other author read

Restrict file permissions on the credentials file

Grouped from the skills themselves: near-identical wordings counted once, and counted by distinct author, so one author publishing three of these counts once. Length counted with cl100k_base; the agent that loads this file may tokenize it differently.