Single tool with adequate naming and schema, but description lacks LLM-optimization guidance. Parameter descriptions are present but generic. No error handling guidance, no output schema documentation, and no indication of pagination support despite returning lists. Tool name 'search_photos' correctly uses verb_noun pattern. Input schema is complete with types and defaults, but output is documented only in the docstring, not as a structured schema definition visible to the MCP protocol layer.

• Define and expose a formal output schema (e.g., via tool metadata or response type annotation) documenting UnsplashPhoto fields: id (string), description (string|null), urls (object with keys: raw, full, regular, small, thumb), width (integer), height (integer). This enables LLMs to chain results into downstream tools.
• Replace color and orientation parameter descriptions with enum constraints. Instead of 'Color filter (black_and_white, black, white, ...)', use a JSON Schema enum: ["black_and_white", "black", "white", ...]. This prevents hallucinated values.
• Add error handling with actionable recovery messages. Catch HTTPStatusError and return structured errors: 'Authentication failed (401). Verify UNSPLASH_ACCESS_KEY is set and valid.' or 'Rate limit exceeded. Retry after 60 seconds.' This guides LLM retry logic.
• Include pagination metadata in response: add 'total' (total matching photos) and 'has_more' (boolean) fields to indicate whether additional pages exist. Document in tool description: 'Returns up to per_page results. Use page parameter to fetch subsequent pages.'
• Enhance tool description with WHEN guidance: 'Use this tool to find images by keyword, color, or orientation. Useful for visual research, content curation, or illustration sourcing. Requires UNSPLASH_ACCESS_KEY environment variable.'