Get Pexels Photo

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

Annotations already provide readOnlyHint and openWorldHint, but the description adds value by disclosing the response structure (src field with named pre-sized URLs) and offering guidance on choosing the closest fit. This goes beyond the annotations and gives actionable behavioral context.

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?

The description is concise, with two short sentences that front-load the purpose and then provide practical guidance on URL selection. No wasted words or redundant fluff.

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?

For a simple single-parameter read-only tool, the description adequately covers return content, usage tip, and safety (via annotations). Although no output schema exists, the description highlights key response aspects like src sizes and courtesy credit, making it complete for the task.

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 fully documents the single id parameter with type, bounds, and a clear description, so coverage is 100%. The description only restates 'numeric ID' and does not add new parameter semantics. The baseline of 3 applies due to complete schema coverage.

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 clearly states the tool retrieves a single Pexels photo by its numeric ID, with specific return details (pre-sized URLs, courtesy credit). It is distinct from sibling search/curated/list tools, which focus on multiple results or collections.

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 implies use when you already have a specific photo ID and need full details. It does not explicitly mention alternatives or when-not-to-use, but the singular 'get by ID' scope makes the context clear. Without explicit exclusions, it falls short of a 5.

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