Two well-defined tools with complete input schemas, clear descriptions in Japanese, and proper parameter typing. Both tools are read-only, offline postal/address lookups with sensible defaults (limit clamped 1 - 200, default 50). Descriptions are concise (120 - 180 chars) and explain use cases. However, output schemas are not formally documented in the code, only inferred from JSON.stringify() calls. Parameter descriptions are present but minimal (e.g., 'limit' lacks range/default clarity in schema). Error messages are actionable but responses are unstructured JSON strings rather than typed objects. No tool annotations (readOnlyHint, idempotentHint) despite both tools being read-only and idempotent.

• Add formal output schema documentation to both tools. Define the structure of 'records' array (fields: zipcode, prefecture, city, town, etc.) and top-level response fields.
• Enhance 'limit' parameter description: '返却件数の上限(1 - 200、既定50)' to make bounds explicit in the description text.
• Add tool annotations: set readOnlyHint: true and idempotentHint: true on both tools to signal safe retry behavior.
• Implement structured error responses with error codes (e.g., 'INVALID_ZIPCODE', 'EMPTY_QUERY') and classification hints (retryable: false, userFixable: true) instead of JSON-stringified messages.
• Remove example values from parameter descriptions; replace with format constraints (e.g., 'zipcode: 3 - 7 digits, hyphens and full-width digits accepted') or a regex pattern in the schema.