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

Annotations only declare destructiveHint=true; the description adds genuinely useful implementation context — that it internally GETs the current booking and PUTs the full booking back with only your changes applied. This read-modify-write semantics is exactly what prevents an agent from assuming partial-field PUTs and clobbering data. It stops short of stating permission requirements or what happens to fields left unspecified.

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 verb and the mutable surface, followed by the one behavioral detail that matters (merge semantics). No filler or restatement of the name.

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 tool with no output schema and only a destructiveHint annotation, the description supplies the essential mental model (merge-then-PUT, reschedule alternatives). Minor gaps remain around notifyUsers/notifyCustomer defaults and error/irreversibility behavior, but nothing that would cause a misinvocation.

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 already 83%, so the baseline is 3, but the description adds real meaning: it groups eventId vs startTime/endTime as the two alternative reschedule routes and frames peopleNumbers/options/resources as replacement-style changes. This routing information is not derivable from the flat schema.

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 ('Change an existing booking') plus the categories of change (reschedule, participant counts, options, resources, external reference), and the reschedule routes are named explicitly. An agent can distinguish this from bookeo_create_booking and bookeo_cancel_booking without opening either 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?

The description implies the context (modifying an existing booking, reschedule via eventId or startTime/endTime) but never states when to use this versus siblings like bookeo_create_hold or bookeo_cancel_booking, nor any preconditions such as needing the booking to be in a mutable state. Usage is inferable but not spelled out.

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