postgres

1---
2name: postgres
3description: "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."
4license: Apache-2.0
5metadata:
6  author: sanjay3290
7  version: "1.0"
8---
9 
10# PostgreSQL Read-Only Query Skill
11 
12Execute safe, read-only queries against configured PostgreSQL databases.
13 
14## Requirements
15 
16- Python 3.8+
17- psycopg2-binary: `pip install -r requirements.txt`
18 
19## Setup
20 
21Create `connections.json` in the skill directory or `~/.config/claude/postgres-connections.json`.
22 
23**Security**: Set file permissions to `600` since it contains credentials:
24```bash
25chmod 600 connections.json
26```
27 
28```json
29{
30  "databases": [
31    {
32      "name": "production",
33      "description": "Main app database - users, orders, transactions",
34      "host": "db.example.com",
35      "port": 5432,
36      "database": "app_prod",
37      "user": "readonly_user",
38      "password": "your-password",
39      "sslmode": "require"
40    }
41  ]
42}
43```
44 
45### Config Fields
46 
47| Field | Required | Description |
48|-------|----------|-------------|
49| name | Yes | Identifier for the database (case-insensitive) |
50| description | Yes | What data this database contains (used for auto-selection) |
51| host | Yes | Database hostname |
52| port | No | Port number (default: 5432) |
53| database | Yes | Database name |
54| user | Yes | Username |
55| password | Yes | Password |
56| sslmode | No | SSL mode: disable, allow, prefer (default), require, verify-ca, verify-full |
57 
58## Usage
59 
60### List configured databases
61```bash
62python3 scripts/query.py --list
63```
64 
65### Query a database
66```bash
67python3 scripts/query.py --db production --query "SELECT * FROM users LIMIT 10"
68```
69 
70### List tables
71```bash
72python3 scripts/query.py --db production --tables
73```
74 
75### Show schema
76```bash
77python3 scripts/query.py --db production --schema
78```
79 
80### Limit results
81```bash
82python3 scripts/query.py --db production --query "SELECT * FROM orders" --limit 100
83```
84 
85## Database Selection
86 
87Match user intent to database `description`:
88 
89| User asks about | Look for description containing |
90|-----------------|--------------------------------|
91| users, accounts | users, accounts, customers |
92| orders, sales | orders, transactions, sales |
93| analytics, metrics | analytics, metrics, reports |
94| logs, events | logs, events, audit |
95 
96If unclear, run `--list` and ask user which database.
97 
98## Safety Features
99 
100- **Read-only session**: Connection uses PostgreSQL `readonly=True` mode (primary protection)
101- **Query validation**: Only SELECT, SHOW, EXPLAIN, WITH queries allowed
102- **Single statement**: Multiple statements per query rejected
103- **SSL support**: Configurable SSL mode for encrypted connections
104- **Query timeout**: 30-second statement timeout enforced
105- **Memory protection**: Max 10,000 rows per query to prevent OOM
106- **Column width cap**: 100 char max per column for readable output
107- **Credential sanitization**: Error messages don't leak passwords
108 
109## Troubleshooting
110 
111| Error | Solution |
112|-------|----------|
113| Config not found | Create `connections.json` in skill directory |
114| Authentication failed | Check username/password in config |
115| Connection timeout | Verify host/port, check firewall/VPN |
116| SSL error | Try `"sslmode": "disable"` for local databases |
117| Permission warning | Run `chmod 600 connections.json` |
118 
119## Exit Codes
120 
121- **0**: Success
122- **1**: Error (config missing, auth failed, invalid query, database error)
123 
124## Workflow
125 
1261. Run `--list` to show available databases
1272. Match user intent to database description
1283. Run `--tables` or `--schema` to explore structure
1294. Execute query with appropriate LIMIT
130