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

Annotations already declare readOnlyHint=true, openWorldHint=true, destructiveHint=false. The description adds valuable context beyond those: that staff slots follow the member's working hours (not business hours) and exclude their appointments and events. It also names the auth requirement (Cotlet API key with app access).

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, each carrying information: scope, staff behavior exception, downstream usage, and auth. Front-loaded with the core purpose. Could be slightly tighter but nothing is redundant.

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?

No output schema exists, so the description carries the return-value burden: it states it returns open start times. Combined with the staff/business-hours nuance and auth note, an agent has what it needs. Missing only notes on time-zone handling or slot granularity.

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 coverage is 100%, so the schema documents service_id, date, and staff_id with descriptions. The description reinforces the one-service/one-day scope and mentions the staff working-hours behavior, but adds no syntax or format detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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: returns open start times for one service on one day, computed from working hours and existing bookings. It differentiates from sibling setmore_list_appointments by clarifying these are open (bookable) times, not booked appointments.

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?

Explicitly says to pass a start from this list to create_appointment or reschedule_appointment, giving downstream context. However, it does not name alternatives like list_appointments or block_time, nor does it say when NOT to use this tool.

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