mssql_skill

Overview

This skill executes safe, read-only SQL queries against one or more Microsoft SQL Server databases. It auto-selects the best connection based on human-friendly database descriptions and enforces strict safeguards to prevent writes, timeouts, and large-memory results. Use it to explore schemas, list tables, and run SELECT queries for analysis.

How this skill works

The skill reads a connections.json file that lists named database connections with descriptions for intelligent auto-selection. It validates incoming queries to allow only read-only statements (SELECT, WITH, SHOW, EXPLAIN, SP_HELP), blocks multi-statement and write operations, and applies limits (TOP N) and row/column caps for safety. It uses pymssql with TLS and connection/query timeouts and returns trimmed, readable query results.

When to use it

• Query Microsoft SQL Server (MSSQL) databases in read-only mode
• Explore schema, list tables, or inspect column definitions
• Run SELECT queries for reporting, troubleshooting, or ad-hoc analysis
• Check database contents without risking writes or schema changes
• Work across multiple named database connections with intelligent selection

Best practices

• Store connections.json securely and set file permissions to 600 to protect credentials
• Provide clear, concise description fields for each connection to enable accurate auto-selection
• Use the --tables and --schema commands first to inspect structure before querying
• Apply the --limit flag or rely on automatic TOP N insertion for large tables
• Use a db_datareader or similarly limited user account on the server for defense-in-depth

Example use cases

• List configured databases and choose one by description when intent is ambiguous
• Show tables or full schema for a database to discover column names before building queries
• Run SELECT TOP N queries to sample recent orders, users, or transactions for debugging
• Extract metrics or ad-hoc reports with safe limits and column width truncation for readable output
• Verify specific records or counts without risking any INSERT/UPDATE/DELETE activity