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

The annotations declare destructiveHint=true, and the description usefully scopes that destruction — only 'a file that fails the check is deleted' — which is real context beyond the annotation. It also confirms idempotent-style behavior implicitly. It stops short of describing error semantics (does a failed check raise or return a status?) or what happens to the upload_id afterward, so it is strong but not exhaustive.

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 compact sentences, front-loaded with what is checked and what is returned, followed by the deletion caveat and the optionality note. Every sentence carries distinct information; nothing is padding.

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, the description compensates by naming the returned fields (media type, size, dimensions, duration, asset_url). Combined with the optionality and deletion notes, an agent has everything needed to call this correctly and interpret the result.

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% for the single parameter (upload_id, with a description pointing back to create_upload_url), so the schema already carries the semantics. The description adds no syntax or format detail beyond it, making the baseline 3 correct.

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 states a specific verb and resource ('Checks an upload started with create_upload_url') and enumerates exactly what is verified — arrival, size limit, declared type — plus what it reports. It is clearly distinguishable from siblings like create_upload_url and upload_media_data.

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 gives the ordering precondition (must follow create_upload_url), the purpose (obtain asset_url for generation tools), and explicit when-not guidance: 'Generation tools run the same check themselves, so this call is optional.' An agent can decide whether to call it without inference.

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