Search stock photos

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

Annotations already declare readOnlyHint=true and destructiveHint=false, which the description does not contradict. The description adds valuable context beyond annotations: it explicitly requires environment variables (UNSPLASH_ACCESS_KEY or PEXELS_API_KEY) and mentions that results are candidate URLs that must be attributed and passed to create_media. This reveals external dependency and usage behavior not present in annotations.

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 three sentences with zero filler. Each sentence serves a purpose: stating the function, explaining the integration path, and noting the prerequisite. The most important information is front-loaded. It is a model of conciseness and structure.

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?

Given the tool's complexity (external providers, attribution requirement, API key dependency), the description covers the essential operational aspects: what it returns (URLs and attribution), how to chain results into create_media, and required environment setup. While it doesn't describe errors or pagination behavior, those are not critical for basic usage and are implied by the schema. The description is complete enough for an agent to invoke it successfully.

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?

Schema description coverage is 100%, so every parameter (query, per_page, provider, orientation) is already documented with descriptions and enums. The tool description does not add any additional meaning to parameters; it focuses on workflow and prerequisites. Given the high schema coverage, a baseline of 3 is appropriate, and the description does not elevate it further.

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 uses a specific verb ('Search') and names the specific resource and providers ('Unsplash or Pexels'), and clearly states the output ('candidate image URLs with their required attribution'). It differentiates from sibling search tools like search_plugins by focusing on stock photos and even references create_media for integration, making its purpose unmistakable.

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 clear context on how to use the tool (search for photos, then pass the result to create_media), which is a usage guideline. It does not explicitly state when not to use it or name alternatives (e.g., for existing media use list_media), but the context makes the intended workflow clear. The guidance is not misleading; it just lacks explicit exclusions.

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