Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

There are no annotations, so the description carries the behavioral disclosure burden. It reveals a key behavior: search results do NOT include a download link, and the follow-up tool is required. It does not mention authentication, rate limits, pagination behavior, or result ordering, but the disclosed limitation plus metadata mention give moderate transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the action and results, with the critical limitation clearly flagged via [CRITICAL]. Every sentence adds value, and formatting improves scannability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has 4 parameters, no output schema, and no annotations. The description conveys the response is a list with metadata (width, height, aspect ratio) and a missing download link, plus the required next step. It could enumerate the exact return fields or pagination defaults, but it is substantial for a stock-photo search tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema has 100% parameter description coverage, including enums for 'size' and 'orientation'. The description adds no parameter-specific detail beyond the schema, so it sits at the schema-covered baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb ('Search for stock photos on Pexels') and clearly states it retrieves a list matching a query. It distinguishes from the sibling 'get_videos' by topic, and the workflow involving 'get_media_detail' is identified. This is a clear, focused purpose statement.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit context: use this tool to search stock photos, then pass the selected 'id' to 'get_media_detail' for the download link. It does not explicitly exclude video searches or compare to 'get_videos', but the mention of the alternative retrieval tool serves as solid usage guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.