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

Annotations already declare it is a non-destructive write in an open world; the description adds the key side effect that a successful booking fires the existing Cal.com webhook and creates the lead in Pool Founder. That downstream consequence is not derivable from annotations or schema. It omits idempotency behavior and what happens on failure or double-booking.

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 tight sentences: purpose first, then prerequisites/required inputs, then the downstream effect. No filler and no repetition that isn't load-bearing for invocation.

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 write tool with no output schema, the description covers the trigger condition, required inputs, and the resulting lead creation, which is what an agent most needs. It could still say what the tool returns on success (confirmation id, booked time) to close the remaining gap.

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 all seven parameters are already documented, including the 'start' constraint. The description repeats the four required fields and the exact-start requirement without adding new syntax, format, or default information beyond the schema (timeZone default, phone formatting, notes are all schema-only). Baseline 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 ('Book'), resource ('Pool Pro Florida appointment'), and provider ('through Cal.com'), plus the precondition that the customer has already selected a time. An agent can distinguish this from get_available_times and create_lead without opening 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?

Explicitly says when to call it ('after the customer has selected an available time') and ties the required 'start' value to the get_available_times output, which is strong context. It stops short of naming create_lead as an alternative or explicitly telling the agent not to call it, though the webhook note implies the lead is created automatically.

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