SQL Server MCP has well-structured tool definitions with consistent naming (verb_noun pattern: select, insert, update, delete, createTable, etc.) and comprehensive parameter schemas. All 16 tools have descriptions and input schemas with typed parameters. However, descriptions are often generic (e.g., 'Execute a SELECT query') and lack actionable context for LLM selection. Output schemas are not documented, LLMs cannot predict response structure. Error handling guidance is absent. Parameter descriptions lack constraints (e.g., no mention of SQL injection prevention, parameter validation rules, or expected return formats). The executeTransaction tool combines multiple operations but lacks clear guidance on rollback behavior or partial failure handling.

• Document output schemas for all tools. Example: 'select returns {rows: [{col1: string, col2: number}], rowCount: number, executionTime: number}'. Include pagination fields (offset, limit, total) for list tools.
• Expand descriptions to 50-200 chars with actionable context. Example: 'Execute a SELECT query. Call listTables() first to discover available tables. Returns rows as objects with column names as keys. Use parameters to prevent SQL injection.'
• Add error handling guidance to mutation tools (insert, update, delete, createTable, alterTable). Example: 'On constraint violation, call describeTable() to review schema. On permission denied, verify database user role.'
• Document parameter constraints in descriptions. Example: 'sql (string): SQL statement with parameterized placeholders (@param1). Must use named parameters; positional ? not supported. Validate against SQL injection patterns.'
• Clarify executeTransaction rollback semantics. Example: 'If any step fails, all completed steps are rolled back. Idempotent operations (SELECT) are safe to retry; mutations (INSERT/UPDATE/DELETE) may have side effects if retried without rollback verification.'

Inferred effective spec: 2026-07-28+.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry