cancel_subscription

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It discloses the major side effect of stopping future charges, which is more than a tautological restatement. However, it does not mention reversibility, impact on the current billing period, permissions, or error behavior, so transparency is partial.

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 with no filler. The action is stated first, followed by the key consequence. Every word earns its place.

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 simple one-parameter mutation with no output schema, the description provides enough information to select and invoke the tool correctly. It does not describe the return value or post-cancel subscription state, but these are not essential for correct invocation. Slight deduction for not explicitly routing away from payment-focused siblings.

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?

The sole parameter is fully documented in the schema as 'Subscription ID to cancel', and the description reinforces the by-ID behavior. Since schema description coverage is 100%, the description does not need to add further parameter meaning; it simply meets the baseline.

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?

Clearly identifies the operation (cancel), the target resource (subscription), the scope (active), and the identifier mechanism (by ID). The final clause 'Stops all future charges' adds a concrete consequence that distinguishes this from sibling tools like update_subscription, refund_payment, and void_payment.

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 description states the prerequisite ('active subscription') and the key outcome ('stops all future charges'), giving an agent clear context for when to use it. It does not explicitly name alternatives or exclusions, but the active-subscription qualifier and future-charges wording imply the appropriate use case.

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