Cancel contract product

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

Annotations already indicate destructiveHint=true and readOnlyHint=false. The description adds context by explicitly stating 'DESTRUCTIVE: cancels a live service' and detailing refund modes, reinforcing the destructive nature and elaborating on behavior beyond the annotation. No contradiction with 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 concise and well-structured: the first sentence states the core action, and the second explains refund modes and adds a destructive warning. Every sentence carries meaningful information with no waste.

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 tool with annotations and schema, the description covers the essential purpose, refund control, and the destructive nature. It does not mention refund_source or cancellation_reason (though the schema covers them), nor post-cancellation effects, but overall it is sufficiently complete for an agent to understand the tool's role.

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 80%, so baseline is 3. The description explains refund_mode values (0/1/2) which the schema already covers, and does not add new meaning for contract_id, contract_product_id, refund_source, or cancellation_reason. It provides no additional parameter semantics beyond the schema.

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 clearly states it cancels a single service on a contract, with refund control. The phrase 'single service' distinguishes it from the sibling `cancel_contract`, which cancels the whole contract, so the purpose is specific and unambiguous.

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 implies when to use it: canceling a single service on a contract, and the refund mode details provide options. However, it does not explicitly mention alternatives or when not to use it (e.g., for full contract cancellation), so it lacks clear exclusions but provides enough contextual guidance.

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