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

Annotations already declare non-read-only, non-idempotent, non-destructive behavior, so the safety profile is covered. The description usefully adds the return payload (trusted type, size, media duration), but it does not explain what happens on a repeat call even though idempotentHint=false makes that a real concern, nor any auth/error conditions.

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, zero filler, with the precondition front-loaded before the return description. 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?

For a one-param mutation tool with annotations and no output schema, the description covers the trigger and return values reasonably well. The gap is the undocumented fileKey parameter, which is the one thing an agent must supply, so it is not fully complete.

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?

With a single parameter at 0% schema description coverage, the description must explain fileKey and it does not name it at all. Only the indirect phrase "after the PUT succeeded" hints at where the key comes from; the format and source are left to inference.

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+resource (complete/finish an upload) and adds a precondition ("after the PUT succeeded") that pins the exact lifecycle stage. It does not explicitly name the paired sibling prepare_upload, but the name and phrasing make the pairing obvious enough to distinguish it from the other tools.

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?

"Finish an upload after the PUT succeeded" gives a clear trigger condition for when to call it, which is more than most definitions offer. There is no explicit when-not or named alternative, but the precondition carries the routing decision.

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