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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is partly covered. The description adds genuinely useful context beyond them: that the uploaded package is deleted and that nothing reached Partner Center, which clarifies the blast radius and reversibility expectations.

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, effect-first, with the reassuring Partner Center note as a brief follow-on. No filler, no repetition of the title, and the destructive effect is front-loaded.

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-parameter mutation with no output schema and annotations covering the safety profile, the description supplies the essential state precondition and outcome. Minor gaps remain (what the caller should do afterward, whether the update can be restarted) but nothing blocks correct invocation.

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?

There is a single parameter with 100% schema description coverage ('The releaseId from start_update'), so the schema carries the semantics. The description adds no format, sourcing, or validation detail about releaseId, making the baseline 3 correct.

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 and resource ('cancels an update') plus the exact effect ('deletes its uploaded package'), so an agent knows precisely what it does. It also implies the precondition state (unsubmitted) which separates it from submit_update, but it never names or contrasts a sibling such as discard_listing_changes.

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?

Gives a clear applicability condition: only updates that 'haven't been submitted' can be discarded. There is no explicit exclusion list or pointer to alternatives (e.g., discard_listing_changes for listing-only changes), so it falls short of full when/when-not routing.

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