Get Rakuten Ichiba Bestseller Ranking

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the description does not need to repeat safety. It adds that the tool returns a ranking list with specific fields, but does not describe additional behavioral traits like pagination limits or response size. The description is consistent with 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 concise with two English sentences and a Japanese translation. It front-loads the action and result, with no wasted words. Every sentence adds value.

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 simplicity of the tool (read-only, filtering, pagination via page parameter), the description covers the main purpose, return data, and prerequisite. The lack of output schema is mitigated by the description listing returned fields. Minor omission: no mention of pagination beyond the page parameter in the schema.

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%, with each parameter having a description. The tool description mentions filtering by genre, period, age, and sex, which matches the parameters, but does not add meaning beyond what is already in the schema. Baseline 3 is appropriate.

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 clearly states the tool retrieves the Rakuten Ichiba bestseller ranking, with options for overall or filtered by genre, period, age, and gender. It also lists the returned data (rank, price, review stats, purchase URL). This distinguishes it from sibling tools like ichiba_item_search and ichiba_genre_search.

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 usage context by mentioning the ability to filter and by pointing to ichiba_genre_search for finding genre IDs. However, it does not explicitly state when not to use this tool or contrast with alternatives like ichiba_item_search for non-ranking queries.

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