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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the destructive nature is known. The description adds the claim 'at any time,' implying no restriction, but doesn't disclose post-cancellation effects, reversibility, or idempotency. Minimal extra value beyond annotations.

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?

The description is very short and front-loaded with the purpose. However, the second clause 'Your are free to cancel...' is grammatically flawed ('Your' instead of 'You') and adds little substance, slightly reducing efficiency.

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 four parameters, no output schema, and a destructive operation, a one-line description is insufficient. It does not explain the body parameter, prerequisites (e.g., instance state), or expected result, leaving significant gaps for an agent to invoke correctly.

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%, and the description only references 'by id' (instanceId). It fails to explain the required cancelInstanceBody (containing cancelDate) or x-request-id. The description does not compensate for the low schema coverage.

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?

The description uses the verb 'Cancel' with the resource 'specific instance by id', clearly distinguishing from other cancellation tools (cancelDomain, CancelObjectStorage). It unambiguously states the action and target.

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?

'You are free to cancel a previously created instance at any time' provides clear context that cancellation is permitted without temporal restrictions. It doesn't explicitly exclude alternatives (e.g., stop/shutdown) or mention prerequisites, but the context is sufficient for most usage cases.

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