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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety posture is covered by structured data. The description adds that responses include page and total metadata, which is mild but useful context. It says nothing about rate limits, auth requirements, or data freshness beyond what annotations already cover.

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?

Two sentences, zero padding: the purpose and result scope come first and the sibling routing follows. Every clause earns its place.

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?

An output schema exists, so return values need no explanation, and the description correctly notes page/total metadata. It covers the core call and two alternatives, but leaves the manga_rankings overlap unaddressed and references a filter that the schema does not actually expose.

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 coverage is 100%, so the schema already documents all 8 parameters and the description carries no extra syntax burden. However, it claims 'media-type and minimum-score filters' when the schema exposes no minimum-score parameter (and media-type only loosely maps to 'format'), which slightly muddies rather than clarifies the parameters.

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 states a specific verb and resource ('Fetch ranked anime titles') and scopes the result as an ordered ranking with optional filters. It distinguishes itself from anime_search and anime_airing_schedule, though it never acknowledges manga_rankings, which shares the same shape and could be confused with it.

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?

It explicitly routes the agent away with 'Use anime_search for a title query or anime_airing_schedule for upcoming broadcasts', giving concrete alternatives with conditions. It falls short of a 5 because it offers no guidance on when a ranking call is NOT appropriate and ignores the closest sibling (manga_rankings).

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