This MCP server provides 5 read-only database tools with clear naming (all action verbs: execute, get, describe, sample) and reasonable descriptions. All tools have input schemas with type definitions. However, several definition quality gaps limit the score: (1) Parameter descriptions are sparse or generic, 'The SQL query to execute' and 'Schema name (defaults to public/default)' lack actionable detail about format, constraints, or examples. (2) Output schemas are not documented in the provided code; responses are described in tool descriptions but not formalized. (3) Error handling is mentioned for errorReporting=true but no recovery guidance is visible in the tool definitions. (4) Descriptions are brief (13-90 chars), adequate but below the 50-200 char sweet spot for LLM optimization. (5) No pagination or limit enforcement guidance for list/result-returning tools. The strong points: verb-based naming, consistent parameter types (string/number/enum), and security-conscious design (read-only by default, no credentials exposed).

• Add formal output schemas (JSON Schema or TypeScript interfaces) to each tool definition. Example for execute_query: {type: 'object', properties: {rows: {type: 'array', items: {type: 'object'}}, rowCount: {type: 'number'}, columns: {type: 'array', items: {type: 'string'}}}, executionTimeMs: {type: 'number'}}.
• Expand parameter descriptions with constraints, format, and examples. E.g., 'The SQL query to execute. Must be a SELECT statement. Max 5000 chars. Syntax errors return a 400 with the parse error position.' Or: 'The table name (case-sensitive, may include schema prefix like 'public.users'). Views and materialized views are supported.'
• Add result limits and pagination guidance to execute_query and get_schema descriptions. E.g., 'Returns up to <limit> rows (default 20, max 10000). For larger datasets, use LIMIT/OFFSET in the query or call sample_data for a preview.'
• Add error recovery guidance to each tool description. Example: 'If the query returns a syntax error, check your SQL grammar. If permission denied, the database user may lack SELECT rights. Contact your admin.'
• Extend tool descriptions to 75-150 chars, clarifying WHEN to use each tool. E.g., 'Call describe_table to explore schema and constraints before writing a query. Call sample_data for a quick preview of 5-10 rows without full introspection.'
• Add explicit numeric constraints to limit parameter: minimum 1, maximum 10000, with a note that large limits may timeout.
• Clarify which tools support cross-database/cross-schema queries (if applicable). Does 'describe_table' accept 'other_schema.table_name', or just table names in the current schema?

Inferred effective spec: <=2025-11-25.

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