Cancel Rental

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

Annotations already declare destructiveHint=true and idempotentHint=true, so the description adds context beyond that: full refund, time window, and SMS condition. It does not contradict any annotation. The added specificity about refund and eligibility is valuable, though it doesn't mention failure modes or exact return shape, which is minor given the simple operation.

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 three sentences, front-loaded with the core action and outcome, then adds eligibility constraints. Every sentence carries essential information, and there is no fluff. It is concise and well-structured.

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 mutation tool without an output schema, the description provides enough context: what it does, when it's valid, and what the result is (full refund). The annotations cover the destructive nature. No critical information is missing for an agent to invoke it 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?

The schema has one parameter (rental_id) with a clear description, and schema coverage is 100%. The tool description adds no additional parameter-specific detail, such as format or validation. Per the rubric, with high schema coverage, a 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?

The description clearly states the action (cancel), the resource (a rental), and the outcome (full refund). It also includes specific eligibility conditions, distinguishing it from sibling tools like cancel_order or cancel_all_orders by focusing on rentals. This is a specific, unambiguous purpose statement.

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 explicitly states when to use the tool (within 20 minutes, before SMS received) and when not to use it (past that window, it runs to expiry). It also notes it works for either tier, giving clear context. No alternative tools are named, but the when/when-not guidance is sufficient.

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