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

Annotations state the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=false), and the description adds real context beyond them: the change is asynchronous and patient-mediated (a texted link/button or code), the practice either updates automatically or receives a request, and re-calling returns a live result. That retry/status behavior also explains the non-idempotent annotation. Only auth/permission and failure behavior are left unstated.

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?

Four sentences, front-loaded with the purpose and then the behavioral details, with essentially no filler. It is slightly dense but every sentence carries information an agent needs about how the change actually happens.

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 described, and the description covers the async, patient-driven workflow well for a genuinely complex tool. The gaps are the missing origin/prerequisites for action_id and any failure handling, which keep it from being fully complete.

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 only 40% (date and slot_fingerprint are documented, with helpful cross-references to list_xona_reschedule_times), yet the description itself says nothing about any parameter. With three parameters (kind, action_id, appointment_ref) undocumented in both places, the description fails to compensate for the coverage gap.

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 opening sentence gives a specific verb pair and resource: 'Move or cancel one of the patient's appointments,' which maps cleanly to the cancel/reschedule enum. It is clear enough to act on, but it does not explicitly distinguish itself from adjacent siblings such as list_xona_reschedule_times or the booking-confirmation tools, so it stops short of a 5.

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 (use it when a patient wants an appointment moved or cancelled) and the description sketches the downstream flow, but it never states prerequisites (e.g., where action_id/appointment_ref come from) or when to prefer a sibling tool. There is no explicit when/when-not guidance, so this is minimum-viable rather than strong.

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