Single tool 'analyze_face' has a clear, descriptive docstring (Korean, ~180 chars) and explicit input schema with types and descriptions. However, the output schema is only partially documented in the docstring, no formal JSON Schema definition is visible in the code. Parameter descriptions are present but lack format constraints (e.g., accepted image formats, base64 encoding details). Error handling returns structured dicts but lacks actionable recovery guidance. The tool is read-only and well-intentioned, but schema incompleteness and missing output type definitions prevent a higher score.

• Add formal JSON Schema for the output object, including all nested fields under 'features' with types (float, int, object) and value ranges (e.g., symmetry: 0.0 - 1.0, confidence: 'high'|'low').
• Enhance the 'image' parameter description with explicit constraints: 'Accepted formats: JPEG, PNG. Max size: 10 MB. Encoding: local file path (max 4096 chars), data:image/...;base64,... URI, or raw base64 string.'
• Add recovery guidance to error responses. E.g., 'Image decode failed. Ensure the file is a valid JPEG/PNG or the base64 string is properly formatted.'
• Declare tool annotations in the schema: readOnlyHint=true and idempotentHint=true to signal safety properties to agents.
• Document the 'features' sub-object structure in the docstring with field names, types, and interpretation hints (e.g., 'samjeong: dict with upper/middle/lower stop ratios (0.0 - 1.0)').