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

Annotations already declare destructiveHint=true, so the description supplements the safety profile with concrete consequences: irreversible, frees the place for others, refund minus Stripe's processing fee and BOP's 5.5% + NT$10 fee, and an online cutoff that defaults to 120 minutes before start. These are exactly the irreversibility, cost, and timing facts an agent needs before invoking a destructive mutation, and nothing contradicts the 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?

Three sentences, front-loaded with the core action and eligibility, followed by consequences and constraints; every sentence carries decision-relevant information. It is dense with fee and cutoff detail but none of it is padding.

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 3-parameter destructive mutation with no output schema, the description covers eligibility states, provenance of identifiers, irreversibility, refund economics, and the time window in which online cancellation is possible. An agent has everything needed to call it correctly and warn the customer in advance.

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?

All three parameters are already fully documented in the schema at 100% coverage, including where booking_id and status_token come from, so the description adds no new parameter-level detail. Baseline 3 is appropriate given the schema carries the semantic load.

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 first sentence states a specific verb (cancel) plus the resource and the exact eligible states (confirmed, pending, awaiting_payment), which directly contrasts with the sibling modify_booking and complete_booking. An agent can identify the operation and its accepted inputs without reading the schema.

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?

It gives a clear trigger ('when the customer asks to') and names request_booking as the origin of the booking, plus a precondition drawn from get_business (online_cancellation cutoff, default 120 minutes). It stops short of explicitly routing the agent to modify_booking when the customer wants to change rather than cancel, so alternatives are only partially covered.

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