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

Annotations already carry readOnlyHint and openWorldHint, so the safety profile is covered; the description adds genuine extra context by stating the output ordering (recommendation count) and warning that results may include non-manga media types. It does not mention rate limits or pagination behavior, but the added result-composition caveat is valuable for interpreting output.

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 filler. The what/ordering is front-loaded and the sibling routing follows, which is exactly the order an agent needs.

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 supplies purpose, alternatives, and a result-composition caveat. Slightly incomplete only in that it omits any lead-in guidance for where the required id comes from, though manga_search is named.

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 id, page, and per_page are already documented in the schema; the description only echoes the 'one manga title' scoping. Baseline 3 is appropriate when the schema does the parameter heavy lifting.

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 (fetch) plus the exact resource (titles AniList users recommend alongside one manga title) and the ordering rule (recommendation count). It also names the sibling tools it is NOT, so an agent can separate it from manga_search, manga_title, and anime_title_recommendations without opening any 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?

Routes the agent explicitly: manga_search to resolve an id, manga_title for details, anime_title_recommendations when the source title is an anime. That covers the main alternatives, though it never states the precondition directly ('use this once you already have a manga id') or any when-not-to-use case.

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