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

Annotations already indicate destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the cancellation behavior is expected. The description adds valuable context beyond annotations: the ride must not have started, and confirmation with the user is required before invoking the tool.

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?

Three short sentences, each carrying distinct information: what the tool cancels, the precondition, the confirmation requirement, and the required inputs. No filler or repetition of the tool name or title.

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 two-parameter cancellation tool with destructive and idempotent annotations already supplied, the description covers the necessary invocation details: target ride, precondition, confirmation step, and required inputs. It does not describe the result/response format, but no output schema exists and the action is straightforwardly conveyed by the verb.

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 coverage is 0%, so the description must compensate. It identifies both required parameters and adds meaning to rider_phone as 'the rider phone used to book.' However, it does not elaborate on ride_id or provide format/usage details beyond what the schema's min/max lengths already state.

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 states a specific action ('Cancels'), a specific resource ('a BinaSmart ride'), and a clear precondition ('has not started yet'). This distinguishes it from sibling tools like request_ride, quote_ride, and get_ride_status without needing to inspect their schemas.

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 gives clear usage context: only cancel rides that have not started, and confirm with the user first. It does not explicitly name alternative tools or state when not to use it, but the precondition and confirmation requirement provide solid operational guidance.

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