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

Annotations declare destructiveHint=true, but the description adds the crucial detail that the change cannot be undone through the API and that a new booking is the recovery path. That operational consequence goes meaningfully beyond the annotation, though it says nothing about auth scope or side effects on notifications/billing.

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 sentences plus the endpoint mapping; the irreversibility warning is front-loaded where it matters. Every clause earns its place with no filler.

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 two-parameter mutation with no output schema, the description covers the essential risk and recovery path, and the annotations carry the safety profile. It could still mention what the response confirms, but nothing an agent needs to invoke it correctly 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 both parameters are already documented by the schema. The description only notes that the reason is optional, which is already evident from the required list — baseline 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?

States a specific verb (cancel) and resource (appointment), and the sibling set (create/get/update/list appointments) makes the distinct action unambiguous. An agent can tell exactly which operation this is without opening 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?

Cleanly states the operating context: cancellation is irreversible and a replacement must be booked, so the agent knows when this tool is appropriate. It stops short of naming alternatives (e.g., update_appointment for rescheduling) or when not to cancel, so it is clear context rather than full routing guidance.

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