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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds the return field details and the Kitsu source, but it doesn't disclose error handling, rate limits, or any fetch-specific pitfalls. This is minimal extra behavioral information.

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?

One sentence that is front-loaded with the action and resource, followed by a concise list of return fields. No redundancy.

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 read-only fetch tool, the description covers what is fetched, by what identifier, and what is returned. Combined with the output schema and annotations, it forms a complete picture.

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?

With 0% schema coverage, the description provides critical semantics: the id is a Kitsu numeric ID. This fully compensates for the schema's lack of parameter description.

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 ('Fetch') and resource ('Kitsu anime entry'), and lists the returned fields. It clearly differentiates from sibling tools like search_anime and top_anime by specifying a numeric ID lookup.

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 usage when a numeric Kitsu anime ID is known, which suggests it is for direct lookups rather than search. It does not explicitly name alternatives or exclusions, but the context is clear enough for an agent to choose it over search_anime.

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