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

Annotations already declare destructiveHint=true, idempotentHint=true, openWorldHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuine value beyond them by disclosing state-dependent behavior and the fact that approved bookings are out of scope here and the response explains the alternative path. It does not detail auth requirements or what the returned payload looks like.

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 tight sentences with the core action front-loaded, followed by the exclusion and a short caution. Every sentence carries weight, though the standalone 'Ask the customer first' is slightly abrupt and the state enumeration could be marginally more compact.

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, open-world two-parameter mutation tool with no output schema, the description covers the essentials: what it cancels, the state conditions, the exclusion, and that the response tells the caller how to proceed for approved bookings. It is close to complete, missing only richer detail on the response payload or auth expectations.

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%, so the schema already documents both `token` and `reference` as coming from book. The description adds no syntax or format detail beyond that, so the baseline 3 applies; the 'made through this door' phrasing is contextual rather than parameter-specific.

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 (cancel) and resource (booking) and goes further by splitting the action into two distinct states: withdrawing a still-waiting request versus cancelling a business-confirmed booking. An agent immediately understands what is being cancelled and under which conditions, with no overlap among the read-oriented siblings (book, find_times, get_booking, get_business).

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 explicit when-to-use conditions (pending request, or a booking the business confirmed at once) and an explicit when-not-to-use exclusion: a business-approved booking must be changed with the business directly. It also adds a procedural prerequisite, 'Ask the customer first', leaving little to inference.

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