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

Annotations already cover readOnly, non-destructive, and closed-world, so the marginal value here is real: the description discloses that results are unpaged and therefore potentially large, describes the per-record payload, and warns that tags reflect store/press/GameGene labels rather than creator self-description. That provenance caveat is substantive behavioral context an agent could not get from structured fields.

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?

Front-loaded with the purpose, then payload shape, then the optional filter, then the semantic caveat and the paging note — a sensible order with no filler. It is dense but every sentence carries information; only the tag-provenance remark is slightly wordy.

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 and no schema descriptions, the description does the necessary work: it explains the return payload, the filter semantics, and the absence of pagination. The only remaining gap is guidance on result volume or how to narrow when the full dump is too large, which matters for a 'return everything' tool.

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 0% — the tags property has no description at all — so the description must carry the meaning, and it does: it gives concrete example values (['survivors-like'], ['horror']) and specifies OR matching ('そのどれかが付いた作品だけ'). It does not restate the schema's maxItems=10 / maxLength=40 bounds, so the size constraint remains only in the schema.

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 first sentence names a specific verb and resource ('GameGene が記録している作品を全件返す'), and the description then enumerates exactly what each record carries (題・ジャンル・年, gene slugs, tags). It distinguishes itself from the singular gamegene_game by emphasizing '全件' and from gamegene_genes by describing the pairing, though it never names gamegene_search as the filtered alternative.

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 clearly states the two usage modes: no argument for the complete dump, and a tags array for filtering. It also tells the agent why to pick this over paging-based siblings ('ページングしない'), but it does not explicitly exclude or route to gamegene_search / gamegene_popular / gamegene_recent when a narrower query is intended.

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