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

The description states 'Safe to repeat', which asserts retry/idempotency safety, while annotations declare idempotentHint: false — a direct conflict about what happens on a repeated call. The rest of the disclosure (409/422/502 semantics, the old cover being replaced, non-confirmation on 502) is genuinely useful and consistent with destructiveHint: true, but the retry claim is exactly the property the annotation denies, so an agent cannot trust it.

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?

One dense sentence, front-loaded with the workflow position and the action, then the validation performed, then the failure codes. Nothing is wasted, though the semicolon-chained clauses make it slightly hard to scan.

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 still covers the outcome ('publishes it and puts it into its slot', 'replaced' names the removed cover) and the principal error contract. Combined with annotations that already flag the destructive write, an agent has enough to call it correctly, apart from the unresolved retry semantics.

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?

Both parameters have 100% schema coverage and the schema already says where each id comes from (start_cover_upload, list_applications). The description adds no further meaning to applicationId or mediaId, so the schema does the work; baseline 3.

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?

Names a specific verb and resource (checks, publishes, and slots a cover file) and anchors itself in the upload workflow as 'Step 3 of 3, after the PUT'. It is unmistakable next to start_cover_upload, which begins the sequence, and it names the observable result ('replaced' names the cover taken out).

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?

States the prerequisite (must follow the PUT), the failure modes that tell the agent what to do instead (409 when nothing is uploaded, 422 when the file does not fit, with the instruction to 'start a new upload'), and the retry posture ('Safe to repeat'). This is explicit when/when-not guidance rather than an implied use case.

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