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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds real value on top: the gym's cancellation deadline applies and a late cancel may count as used — a consequence an agent would otherwise not know to warn the user about.

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?

Two sentences, no filler. The core action is front-loaded and the deadline caveat follows as the secondary point an agent needs before confirming.

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?

With four fully documented parameters, rich annotations and no output schema, the description covers what an agent needs to invoke it safely. It stops short of stating what the response contains or how to report the outcome to the member.

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 class_id, date, gym and locale are all documented in the schema itself, including where ids come from. The description adds only the implicit scoping to the signed-in member, so the baseline of 3 applies.

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 names a specific verb and resource ("Cancels the signed-in member's booking (or waitlist spot) for a class"), and the parenthetical expands scope to cover waitlist entries, which the name alone would not convey. It is clearly the inverse of book_class, though it never names a sibling explicitly.

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?

Usage is implied rather than stated: the agent can infer this is the tool for undoing a booking, and the deadline note hints at a condition. But there is no explicit guidance such as verifying the booking exists first (my_bookings) or what to do if the deadline has already passed.

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