serverless-mcp demonstrates solid definition quality with well-structured tool schemas and clear descriptions. All 7 tools have descriptions (10-150 chars baseline = 194 chars avg in production; these average ~95 chars, within good range). Input schemas are present and typed for all tools. However, there are gaps in parameter-level documentation, output schema documentation, and error handling guidance. The server follows tool naming conventions (verb_noun pattern: get_*, all action verbs). Parameter descriptions exist but some lack constraint details (e.g., dimensionKey enum is well-documented, but filter objects lack structure). No tool annotations are present (readOnlyHint, destructiveHint, idempotentHint). Tools are well-composed with clear single responsibilities.

• Add explicit output schema definitions for each tool, documenting all returned fields, their types, and when they are present. Example: 'Returns: {today: string (ISO 8601), current_month: string, current_year: number, note: string}'
• Replace generic 'filter' object parameters with typed objects. Define Filter as a schema with specific field types (e.g., filter: {dimension: {key: string, values: [string]}, costCategory: {key: string, values: [string]}}). This enables validation and clearer LLM guidance.
• Add tool annotations: set readOnlyHint=true for all 7 tools in the tool definition metadata. This signals to clients and LLMs that these tools are safe to retry and cannot cause side effects.
• Enhance error messages with recovery guidance. Example: 'Failed to get dimension values: [error]. Verify dimensionKey is valid (SERVICE, REGION, INSTANCE_TYPE, etc.) or try searching with a different date range.' Reference the valid enum for dimensionKey in the error.
• Document pagination support in get_dimension_values and get_tag_values. Add NextPageToken parameter to both tool definitions if large result sets are expected. Document the pagination contract in tool descriptions.
• Consider splitting 'get_cost_and_usage_comparisons' into 'compare_cost_and_usage' or creating a higher-level tool for period-over-period analysis. The current name is clear but suggests bundled functionality.
• Add parameter constraints to 'context' enum in get_dimension_values in the parameter description to reinforce valid values beyond the schema.

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

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