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

Annotations already cover read-only/idempotent/open-world safety, and the description adds value beyond them: the API-key setup requirement, the return payload contents, and the fact that it runs immediately without approval in the Royally environment. It does not cover pagination limits, rate limits, or empty-result behavior.

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?

Purpose is front-loaded and each sentence covers scope, return values, downstream usage, and prerequisites. The final "Through Royally: its server marks it read-only..." sentence is awkwardly worded but still conveys useful execution context.

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?

With no output schema, the description usefully lists returned fields (URLs, thumbnails, dimensions, attribution) and names the auth prerequisite. It is complete enough to invoke correctly, missing only pagination/empty-result expectations.

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% and enum values are documented, so the schema already carries the parameter burden. The description only reinforces the provider-connection default implicitly via the API-key note, adding little new parameter meaning.

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?

States a specific verb ("Searches") and names the exact resource domain (Unsplash, Pexels, Pixabay) plus what it returns. An agent can distinguish it from siblings like list-media or get-media without opening the schema.

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?

Explicitly routes the returned URLs to the downstream tools sideload-image or add-stock-image, and states the API-key prerequisite. It stops short of naming when NOT to use it, but the context for calling it is unambiguous.

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