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

Annotations already declare readOnly/non-destructive, so the description wisely focuses elsewhere: it lists the exact status states, notes whether the file is ready for download, and discloses the guest-vs-API-key limits. The auth note is real context, though it is somewhat generic to the whole server rather than this call.

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 first three sentences are well front-loaded and earn their place, but the trailing sentence about stdio API keys, guest uploads, 100 MB, and selling is off-topic for a status-check tool and dilutes focus.

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 an output schema present, return values need no explanation, and usage guidance plus status enumeration cover the call correctly. The only noise is the tangential credential/marketplace remark, which adds confusion rather than completeness.

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% and the single uploadId parameter is fully documented in the schema, so the description adds nothing about parameter syntax. Baseline 3 applies.

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?

States a specific verb (check) and resource (processing status of a previously uploaded file), and immediately enumerates the status values returned. It is clearly distinguishable from siblings like list_storage, get_download_url, and transfer.

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 it is rarely needed because 'transfer' handles polling automatically, and narrows use to timed-out uploads or manual inspection. Both the when-to-use and the better alternative are named.

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