Cancel Subscription Purchase

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

With no annotations, the description carries the full burden of disclosing behavior, but it only says 'cancel' without explaining whether this stops renewals, refunds money, revokes access, or is reversible. The schema's cancellation_type field hints at behavior, but the description itself adds no transparency.

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 text is short and free of fluff, but it is under-specified rather than usefully concise. It repeats the title and lacks the scoping, behavioral, or usage detail that would earn a higher score.

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?

The parameter schema and output schema cover some mechanical details, but the tool is one of several similar subscription-purchase mutations. The description gives no information about effect, cancellation types, or when to choose this over revoke/defer/refund, making it incomplete for correct tool selection.

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%, and the schema already documents package_name, purchase_token, and cancellation_type with default values. The description adds no additional parameter meaning, so the baseline of 3 is appropriate.

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 the core action ('Cancel a subscription purchase') and names a clear resource, but it is vague about what 'cancel' means in this API and does not differentiate from sibling tools like revoke_subscription_purchase or defer_subscription_purchase. It essentially restates the title without adding operational detail.

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?

Provides no guidance on when to use this tool versus the many overlapping subscription-related siblings. There are no conditions, prerequisites, or exclusions stated.

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