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

Goes well beyond the annotations: it discloses soft-delete semantics ('kept with status CANCELED, never deleted'), which clarifies what destructiveHint=true actually means here, and pre-announces the return payload including the patient-notification flag. This is exactly the context an agent needs before invoking a mutation.

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 short clauses, front-loaded with the action and followed by the non-deletion guarantee and the exclusion. No filler, nothing repeated from the title.

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?

An output schema exists, so return values need not be detailed, and the mutation semantics plus the concurrency guard are covered between description and schema. The only gap is that no prerequisites (e.g., permissions or subscription state, given the presence of get_subscription_status) are mentioned for this mutation.

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%, and both parameters (appointmentId, expectedLastEditTime) are already documented in-schema including the optimistic-concurrency refusal behavior. The description adds no meaning beyond that, 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?

States a specific verb+resource (cancel a patient's appointment) and immediately delimits it against reschedule_appointment with 'Not for moving it to another time.' An agent can distinguish it from the similar-sounding sibling without reading any 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?

Gives an explicit trigger ('when someone asks to cancel') and an explicit exclusion ('Not for moving it to another time'), which routes the moving-to-another-time case to reschedule_appointment. Both when-to-use and when-not are present, with the alternative identified functionally.

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