MSSQL Read-Only Query Skill
Execute safe, read-only queries against configured Microsoft SQL Server databases.
Requirements
- Python 3.8+
- pymssql:
pip install -r requirements.txt
Setup
Create connections.json in the skill directory or ~/.config/claude/mssql-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": 1433,
"database": "app_prod",
"user": "readonly_user",
"password": "your-password",
"encrypt": true,
"tds_version": "7.3"
}
]
}
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: 1433) |
| database |
Yes |
Database name |
| user |
Yes |
Username |
| password |
Yes |
Password |
| encrypt |
No |
Enable TLS encryption (default: false) |
| tds_version |
No |
TDS protocol version: 7.0, 7.1, 7.2, 7.3, 7.4 (default: auto) |
Usage
List configured databases
python3 scripts/query.py --list
Query a database
python3 scripts/query.py --db production --query "SELECT TOP 10 * FROM users"
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
Note: MSSQL uses TOP N instead of LIMIT. The --limit flag automatically inserts TOP N after SELECT.
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 enforcement: Query validation blocks write operations (use a
db_datareader role user for server-side protection)
- Query validation: Only SELECT, SHOW, EXPLAIN, WITH, SP_HELP queries allowed
- Single statement: Multiple statements per query rejected
- TLS support: Configurable encryption for secure connections
- Query timeout: 30-second timeout enforced via pymssql
- Connection timeout: 10-second login timeout
- 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 |
| TDS version error |
Try "tds_version": "7.3" or "7.4" |
| Encryption error |
Set "encrypt": true for Azure SQL |
| 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 (auto-converts to TOP N)
1---2name: mssql3description: Execute read-only SQL queries against multiple Microsoft SQL Server databases. Use when: (1) querying MSSQL/SQL Server 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-2.05---6# MSSQL Read-Only Query Skill78Execute safe, read-only queries against configured Microsoft SQL Server databases.910## Requirements1112- Python 3.8+13- pymssql: `pip install -r requirements.txt`1415## Setup1617Create `connections.json` in the skill directory or `~/.config/claude/mssql-connections.json`.1819**Security**: Set file permissions to `600` since it contains credentials:20```bash21chmod 600 connections.json22```2324```json25{26 "databases": [27 {28 "name": "production",29 "description": "Main app database - users, orders, transactions",30 "host": "db.example.com",31 "port": 1433,32 "database": "app_prod",33 "user": "readonly_user",34 "password": "your-password",35 "encrypt": true,36 "tds_version": "7.3"37 }38 ]39}40```4142### Config Fields4344| Field | Required | Description |45|-------|----------|-------------|46| name | Yes | Identifier for the database (case-insensitive) |47| description | Yes | What data this database contains (used for auto-selection) |48| host | Yes | Database hostname |49| port | No | Port number (default: 1433) |50| database | Yes | Database name |51| user | Yes | Username |52| password | Yes | Password |53| encrypt | No | Enable TLS encryption (default: false) |54| tds_version | No | TDS protocol version: 7.0, 7.1, 7.2, 7.3, 7.4 (default: auto) |5556## Usage5758### List configured databases59```bash60python3 scripts/query.py --list61```6263### Query a database64```bash65python3 scripts/query.py --db production --query "SELECT TOP 10 * FROM users"66```6768### List tables69```bash70python3 scripts/query.py --db production --tables71```7273### Show schema74```bash75python3 scripts/query.py --db production --schema76```7778### Limit results79```bash80python3 scripts/query.py --db production --query "SELECT * FROM orders" --limit 10081```8283**Note**: MSSQL uses `TOP N` instead of `LIMIT`. The `--limit` flag automatically inserts `TOP N` after SELECT.8485## Database Selection8687Match user intent to database `description`:8889| 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 |9596If unclear, run `--list` and ask user which database.9798## Safety Features99100- **Read-only enforcement**: Query validation blocks write operations (use a `db_datareader` role user for server-side protection)101- **Query validation**: Only SELECT, SHOW, EXPLAIN, WITH, SP_HELP queries allowed102- **Single statement**: Multiple statements per query rejected103- **TLS support**: Configurable encryption for secure connections104- **Query timeout**: 30-second timeout enforced via pymssql105- **Connection timeout**: 10-second login timeout106- **Memory protection**: Max 10,000 rows per query to prevent OOM107- **Column width cap**: 100 char max per column for readable output108- **Credential sanitization**: Error messages don't leak passwords109110## Troubleshooting111112| Error | Solution |113|-------|----------|114| Config not found | Create `connections.json` in skill directory |115| Authentication failed | Check username/password in config |116| Connection timeout | Verify host/port, check firewall/VPN |117| TDS version error | Try `"tds_version": "7.3"` or `"7.4"` |118| Encryption error | Set `"encrypt": true` for Azure SQL |119| Permission warning | Run `chmod 600 connections.json` |120121## Exit Codes122123- **0**: Success124- **1**: Error (config missing, auth failed, invalid query, database error)125126## Workflow1271281. Run `--list` to show available databases1292. Match user intent to database description1303. Run `--tables` or `--schema` to explore structure1314. Execute query with appropriate `--limit` (auto-converts to TOP N)
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