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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds one genuinely useful behavioral fact — that the download URL is absolute and temporary (i.e., expires) — but says nothing about job states, retention, or polling cadence, so it only partially lightens the annotation burden.

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 short sentences, no padding, with the core purpose front-loaded and the download-URL note following. Nothing here could be cut without losing information.

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 needn't be restated, and annotations cover the safety profile. However, for a polling tool the description should mention how to obtain job_id and what intermediate (non-completed) states look like — those gaps remain for the agent.

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% for the single job_id parameter, and the description does not explain where the job_id comes from, its format, or how it relates to the conversion request. With one undocumented required parameter, the description needed to compensate and does not.

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?

"Check a XLSX.now conversion job" gives a specific verb and resource, and the tool is clearly a status poller rather than a converter or listing tool. It stops short of explicitly contrasting itself with convert_image_url or list_converters, but an agent can still place it correctly among the siblings.

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 wording implies the tool is called on an existing job, but it never states when to call it (after submitting a conversion), whether to poll or wait, or what to do if the job is still running. Usage is inferable from the name and the word "completed," not stated.

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