Three well-named, read-only tools with clear descriptions (150 - 200 chars each) and complete input schemas. All parameters are typed and described. However, output schemas are not formally documented, only inferred from code. Error handling is minimal (generic error objects). No parameter constraints (enums, ranges) despite opportunities (e.g., limit should have min/max). Missing idempotent/readOnly hints. Descriptions avoid examples but lack dependency guidance (e.g., 'Call get_snp first to verify the SNP exists before querying associations'). Tool composition is sound, each does one thing, names are action-verb clear, and chaining is feasible (rsid flows through all three).

• Add formal output schema documentation to each tool. Example for get_snp: 'Returns {rsid: string, functional_class: string, locations: [{chromosome: string, position: number, region: string}], genes: [{gene: string, distance: number, upstream: boolean, downstream: boolean}]}'.
• Declare numeric parameter constraints in schema: limit as {type: 'number', minimum: 1, maximum: 100} and in description: 'Max results to return (1 - 100, default 20).'
• Enhance error messages with recovery hints. E.g., 'SNP not found. Verify the rsID format (e.g., rs7329174) or call studies_by_trait() to discover SNPs associated with a trait.'
• Add readOnlyHint: true to all three tool definitions to signal to LLMs that these are safe to retry and do not modify state.
• Document pagination behavior: 'Returns up to [limit] results. If total > limit, results are truncated; call again with a different trait/rsID to explore further.' Clarify whether the API supports offset/cursor pagination.