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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive), so the bar is lower; the description usefully adds the validation semantics (size, hash, type checks) and explains what 'ready' means. It stops short of describing polling behavior or error/failure states, so not 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?

Two sentences, zero padding, with the core meaning (arrival + checks) front-loaded and the downstream usage (upload_reference feeding an upload_id argument) placed second. Every clause earns its place.

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 shapes need not be re-explained, and the description still adds the key semantic link between upload_reference and download-side upload_id. The only real omission is the origin/lifecycle of the input upload_id relative to upload_prepare.

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 upload_id parameter, and the description never explains where that id comes from or its expected form. It does clarify the related upload_reference value, but that is an output, not the input parameter, so compensation for the coverage gap is partial.

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 resource (a prepared upload) and what the tool reports (whether it arrived and passed size/hash/type checks). It connects conceptually to upload_prepare via 'prepared upload' but never names a sibling, so differentiation is implied rather than explicit.

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?

Usage is only implied: an agent infers it should be called after preparing an upload. There is no explicit when-to-use guidance, no statement of what to do on failure, and no routing against the other upload siblings (prepare/request/from_url).

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