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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds genuinely new context: the call is free, it returns a download link and a ready card, and it should not be polled. It does not describe what a not-ready response looks like, which keeps it from a 5.

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?

Four short sentences, front-loaded with the purpose and followed by cost, parameter handling and loop guidance, with no filler. The opening sentence is slightly awkward grammatically ('Whether an ebook... is ready'), which is the only blemish.

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?

There is no output schema, so the description rightly states the return payload (download link and ready card). Combined with cost and non-polling guidance, an agent has enough to call this correctly; only the shape of an unsuccessful/not-ready result is left unspecified.

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 description coverage is 0%, so the description must carry the semantics, and it does explain the key ambiguity of job_id (omit it to get the most recent of that kind). The product parameter's four valid values are restated from the enum and add no meaning beyond the schema, so the compensation is partial rather than complete.

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 names a specific check operation over a specific set of resources (ebook, planner, spreadsheet, website) and states what the caller gets back (readiness status, download link, ready card). It implicitly separates itself from check_video/check_animation/check_social_post by naming the product kinds it handles, though it never names those siblings explicitly.

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?

Explicitly says when to call ('when the user asks'), how to call it correctly ('call once... not in a loop'), and how to handle the optional parameter ('leave job_id out for their most recent one of that kind'). The anti-polling instruction is exactly the kind of guidance an agent needs and would otherwise have to guess.

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