Stoolap MCP provides 12 well-structured SQL tools with consistent naming (verb_noun pattern: query, execute, begin_transaction, etc.) and clear descriptions (avg ~80 chars, all present). All tools have explicit input schemas with type definitions and parameter descriptions. However, output schemas are not documented, callers cannot predict response structure. Error handling is basic (generic error messages like 'Error: ...' without recovery guidance). No tool annotations (readOnlyHint, destructiveHint) despite clear risk classifications. Parameter descriptions lack format constraints (e.g., savepoint name validation rules). Missing idempotency guidance for transaction tools.

• Document output schemas for all tools. E.g., query returns {rows: Array<Record<string, unknown>>, rowCount: number}; schema returns {tables: Array<{name: string, columns: Array<{name: string, type: string}>}>}.
• Add tool annotations to schema: readOnlyHint=true for query/transaction_query/schema/explain; destructiveHint=true for execute/transaction_execute/commit_transaction; idempotentHint=false for transaction tools.
• Enhance error messages with recovery guidance. E.g., 'no active transaction. Call begin_transaction first.' or 'Invalid savepoint name: must match [a-zA-Z_][a-zA-Z0-9_]* (1-64 chars).'
• Add format constraints to savepoint name parameter: description should include regex pattern and length limits (e.g., 'SQL identifier: 1-64 alphanumeric/underscore chars, starting with letter or underscore').
• Add idempotency notes to transaction tool descriptions. E.g., 'Calling begin_transaction when a transaction is already active returns an error; this is not idempotent. Use rollback_transaction to reset state before retrying.'