Single tool 'get_ziwei' has well-structured input schema with proper Zod validation, regex patterns, enums, and descriptions in Korean. Tool name starts with verb (get_). Description is detailed (180+ chars) and explains purpose, inputs, and outputs clearly. Input parameters all have type constraints and descriptions. However, output schema is not formally documented, the code shows it returns text + PNG or JSON, but no explicit schema definition is visible. Error handling is minimal (no recovery guidance). Overall solid for a specialized domain tool, but lacks output documentation and error patterns expected in production tools.

• Add explicit output schema documentation: define the structure of text response, PNG metadata, and JSON format (12 palaces, major/minor stars, mutations).
• Wrap tool logic in try-catch; return structured error responses with actionable guidance: 'Invalid birthDate format: expected YYYY-MM-DD (e.g., 2000-08-16)' instead of stack traces.
• Add tool annotations: set readOnlyHint=true and idempotentHint=true in registerTool() to signal deterministic, side-effect-free behavior.
• Migrate from STDIO to HTTP+SSE or Streamable HTTP transport to enable remote client access and hosted deployment.
• Add English descriptions alongside Korean for broader LLM compatibility and international use.