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

readOnlyHint=true already tells the agent this is a non-destructive read, so the safety profile is covered. The description adds only the REST endpoint provenance, which is consistent with the read-only annotation but discloses nothing new about rate limits, auth requirements, or whether the returned dates are filtered by existing bookings.

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 compact sentences with zero filler, and the operation scope is front-loaded ahead of the endpoint reference. Nothing is repeated and no sentence is wasted.

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 read-only helper with a fully documented 4-parameter schema and annotations covering safety, the description is essentially sufficient. It could say slightly more about the return shape (e.g. a list of YYYY-MM-DD strings) since no output schema exists, but the phrase 'List dates' largely covers it.

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 month, timezone, calendarID, and appointmentTypeID are all fully documented in the schema itself. The description restates the appointment-type and month concepts but adds no format, default, or interaction semantics beyond what the schema already provides.

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 (List), resource (dates), and two scoping constraints (in a month, for an appointment type), plus the underlying REST endpoint GET /availability/dates. The resource noun 'dates' inherently separates it from acuity_availability_times and acuity_availability_classes without needing to name them.

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 resource and scope ('in a month', 'for an appointment type'), so an agent can infer when this applies versus the times/classes variants. However, there is no explicit when-to-use guidance, no prerequisites, and no statement of when to prefer acuity_availability_times instead.

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