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

Annotations already flag destructive=true and idempotent=false, but the description makes the consequence concrete: attendee and guest emails are sent and cannot be unsent, and repeat calls create a second booking. That is exactly the kind of side-effect detail an agent cannot infer from hints alone.

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 short sentences, front-loaded with the core action, then preconditions, then side effects. No sentence is redundant and each adds a distinct operational fact.

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 12-parameter mutation with no output schema, the definition covers the critical unknowns: prerequisite lookups, custom-field wiring, and irreversible notifications. It stops short of describing failure behavior when a slot is taken or how location/language affect the booking, which would have closed 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?

With 50% schema description coverage, the description usefully explains that additionalResponses holds answers keyed by each bookingField's name and that start must come from find_available_slots. It leaves end, notes, guests, location, language, and metadata unaddressed, so half the parameters still rely on bare schema types.

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?

"Book a slot on an event type" gives a specific verb and resource, and the follow-up sentences tie it to find_available_slots and get_event_type, which separates it cleanly from cancel_booking and reschedule_booking.

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?

It prescribes the exact ordering: call find_available_slots first and pass one of those start times, and consult get_event_type for required bookingFields. It also states the limitation (no internal availability check), so the agent knows the precondition is on it.

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