request_cancellation

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

Goes well beyond the destructiveHint annotation by disclosing the refund consequence ('partial refund if possible'), the two timing behaviors, and the environment prerequisite for enabling destructive calls. This is exactly the operational context an agent needs before invoking an irreversible action.

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 dense sentences with no filler; the destructive warning and env prerequisite are front-loaded rather than buried.

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 destructive, no-output-schema tool, the description covers effect, timing, refund implication, and gating prerequisites. Minor gaps remain (e.g., what confirm/id refer to is left to the schema, and no post-call state is described), but nothing critical is missing.

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 enum values are already documented in the schema, so the description largely restates cancellation_type. Baseline 3 is appropriate; the 'if possible' refund caveat adds only marginal meaning.

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+resource ('Request service cancellation') plus the underlying endpoint (whmcs/request_cancellation), and is clearly distinct from the read-side siblings get_cancellation_requests and delete_cancellation_request.

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 strong preconditions (requires HOSTKEY_ALLOW_DESTRUCTIVE=1) and explains the semantics of each cancellation_type, which tells the agent when each mode applies. It does not, however, explicitly route the agent away from related siblings like delete_cancellation_request.

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