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

Beyond the destructiveHint=true annotation, the description discloses a meaningful side effect: releasing the stock reservation. This tells the agent exactly what changes, adding value without contradicting 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?

One sentence, front-loaded with the action verb, and zero filler. Every word contributes: the operation, the target object, its state, and the resulting side effect.

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 single-parameter destructive tool with annotations already declaring destructiveness, the description is complete. It names the operation, the precondition, and the business impact (stock release), requiring no further info to call 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 100%, so the single parameter is already well-documented. The tool description adds no new parameter-level meaning beyond restating that the intent is pending and to be canceled.

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 a specific verb ('Cancel') and resource ('pending purchase intent'), clearly distinguishing it from sibling tools like purchase_confirm_intent or purchase_create_intent. It states the precise action and the object's state.

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 qualifier 'pending' implies when the tool should be used, but there is no explicit guidance about alternatives or when not to use it. No mention of confirming intents or handling already-confirmed intents; usage context is present but implicit.

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