The server defines one tool (search_photos) with reasonable structure. The tool has a descriptive name starting with a verb ('search_'), a clear description, comprehensive input schema with type constraints and enums, and an output schema. However, there are critical issues: (1) the description is in English but input/output parameter descriptions are in Chinese, creating a mixed-language interface that LLMs may struggle with; (2) parameter descriptions in the input schema use example values (e.g., '例如：\'山峰\'、\'日落\'') rather than formal constraints, violating the pattern:tool-description guidance to avoid example values in descriptions; (3) the API key is hardcoded as a default constant in config.go (defaultKey = 'RgkH0m_iWfVsoSuLheI46BAYy1Ig1Ab3vvElYAESZ34'), which is a critical security vulnerability; (4) error handling in HandleSearchPhotos is minimal, no guidance on recovery strategies for common failures like API quota exceeded or network timeouts; (5) the output schema lacks a total/total_pages field that the API returns, limiting pagination support awareness. The schema structure itself is well-formed with proper type definitions, required fields, and enum constraints for order_by and orientation, which are strengths.

• Move the Unsplash API key to environment-variable-only injection; remove the hardcoded defaultKey. Require UNSPLASH_ACCESS_KEY to be explicitly set by the operator.
• Rewrite all parameter descriptions in English (the server's primary language). Replace example values with formal constraints: 'query: Search keyword (required)' instead of 'query: 搜索关键词(例如：\'山峰\'、\'日落\')'; use 'per_page: Number of results per page (1-30, default 5)' instead of '每页返回的照片数量(最多 30 张)'.
• Add pagination metadata to the output schema: include 'total' and 'total_pages' fields from the API response so the LLM knows how many results are available and can plan multi-page queries.
• Enhance error handling: return structured error responses that tell the LLM what to do. E.g., for 401 errors: 'Unauthorized: API key invalid or expired. Set UNSPLASH_ACCESS_KEY environment variable.' For 429: 'Rate limited. Wait 1 hour before retrying.' For 0 results: 'No photos found. Try a different query or adjust filters (color, orientation).'
• Document rate limiting behavior and request timeout (currently hardcoded to 10s in config.go) in the tool description so the LLM knows when to back off.
• Add tool annotations (readOnlyHint: true) since search_photos only reads data and never modifies state.
• Consider adding a second tool (get_photo_details) to fetch metadata on a specific photo_id if deeper integration is needed, but only if the Unsplash API supports it.