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

Annotations only declare destructiveHint=true; the description goes well beyond that by clarifying the cancellation is a soft delete (booking persists, visible via includeCanceled) while seats are freed, and that no cancellation fee is charged. This nuance materially changes how an agent should reason about a "destructive" tool, which is exactly the kind of context annotations cannot convey.

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 front-loaded with the action, with no filler; each adds a distinct fact (soft delete, seat release, no fee). The includeCanceled reference is a slight tangent since it is not a parameter of this tool, but overall it is efficient.

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?

With no output schema, the description carries the burden of explaining effects and does so for the core outcomes (persistence, seat release, fee behavior). Notification and recurring-series behavior are covered in the schema parameter descriptions, so the remaining gaps are minor.

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 six parameters (reason, notifyUsers, notifyCustomer, cancelRemainingSeries, trackInCustomerHistory, bookingNumber) are already documented in the schema. The description adds no parameter-level syntax or semantics beyond that, so the 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 and resource ("Cancel a booking") and even names the underlying API call (DELETE /bookings/{bookingNumber}), so the operation is unambiguous. It does not explicitly contrast with nearby siblings like bookeo_update_booking or bookeo_get_booking, which is the only thing keeping it from 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?

The description explains what cancellation does but never says when to choose it over alternatives (e.g., update_booking for modifications, or a fee-applying path). The note that the cancellation policy is NOT applied hints at a use-case distinction but stops short of naming any alternative or exclusion condition.

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