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

Annotations already declare readOnly=false, destructive=false and idempotent=false, so the safety profile is covered; the description usefully adds that verification of bytes actually happens rather than a no-op finalize. It omits what happens on verification failure (error only, or does the upload become unusable/deleted?) and what the non-idempotent flag means for retries, which are the concrete behaviors an agent would want here.

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?

A single well-formed sentence with the verification action front-loaded and the payoff ('ready to bind') at the end, with no filler. It is slightly compressed for a four-parameter mutation tool, but nothing written is wasted.

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-value description is not required, and the annotations cover the safety profile. Still missing for a lifecycle-mutating tool is failure/retry semantics and where this sits relative to create_upload and generation binding, so an agent could call it at the wrong point in the flow.

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% across 4 parameters, so the description carries the full burden. It references 'declared size, type and checksum', but no size or type parameter exists in the schema, while the actual width/height parameters are never explained and upload_id (the only required field) is unmentioned, leaving the required/optional distinction and the meaning of the dimension overrides undocumented.

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?

Uses a specific verb pair ('Verify ... and return') on a specific resource ('upload'), and the outcome ('ready to bind to a generation') makes the step's role clear. It never names the adjacent siblings (create_upload, update_upload, get_upload, delete_upload), so an agent must infer the distinction from the lifecycle wording alone.

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 phrase 'return the upload ready to bind to a generation' implies this is the terminal step of an upload flow that must precede generation binding, which is useful positioning. However, there is no explicit when-to-use statement, no statement of prerequisites (bytes must already be uploaded), and no routing to alternatives such as request_upload_link or get_upload to check status.

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