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

Provides real behavioral context beyond the annotations: it sends confirmation emails to both provider and customer (toggleable in Settings > Notifications), it can require per-call confirmation, and it needs the user's Cotlet API key with app access. This meaningfully supplements the generic readOnly/openWorld/destructive flags, though it omits failure behavior.

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?

Purpose is front-loaded, but the confirmation-email behavior is stated twice ('Setmore emails the confirmation unless you turned it off' and the longer 'Setmore sends a booking confirmation email to the provider and the customer unless you turned it off...'), which is redundant and bloats the text.

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 mutation tool with no output schema, the description covers the key non-obvious elements: outbound emails, the confirmation gate, and auth requirements, and the schema fully documents inputs. It is close to complete, missing only things like idempotency or error handling.

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 the required fields and the customer vs customer_id vs staff_id relationships are already documented in the schema. The description adds only a general restatement ('one service with a team member at a start time') without new syntax or format detail, so the schema-coverage 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?

Names a specific verb and resource ('Book a service for a customer') and elaborates the shape of the operation (one service, one team member, a start time, existing or new customer). It does not explicitly differentiate itself from siblings like reschedule_appointment or list_appointments, 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?

States you can book for an existing or a new customer and that confirmation is on by default but can be switched off, which implies usage. However it never names an alternative tool or spells out when this is the right call versus reschedule/cancel, leaving selection to inference.

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