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

Annotations already declare destructive=true, idempotent=false, and readOnly=false, but the description adds genuinely useful context beyond them: the cancellation deadline governs the action and a late cancel may count as used, which tells the agent the operation has real consequences. It does not cover error behavior (e.g., no matching booking) but the deadline/consequence detail is a meaningful value-add.

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 tight, front-loaded sentences with no waste. The scope is stated first and the deadline caveat follows, so an agent gets the essential information immediately.

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 destructive cancel tool with annotations that already convey the safety profile and a fully documented schema, the description covers the operation and its key consequence (late-cancel penalty). No output schema is needed and nothing critical to correct invocation is missing.

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 all four parameters (gym, date, locale, class_id) including enums and cross-references to my_gyms/my_schedule. The description adds no parameter-level meaning beyond that, so the 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?

States a specific verb (Cancels) and resource (the signed-in member's booking or waitlist spot) with clear scope. It implicitly reads as the inverse of book_class but never names or explicitly contrasts with any sibling tool.

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 by the purpose and the note that the cancellation deadline applies, but there is no explicit when-to-use guidance, no mention of prerequisites (e.g., an existing booking must exist), and no routing to siblings like my_bookings to confirm a booking first.

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