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

Annotations declare a non-readonly, idempotent, non-destructive write; the description goes well beyond that by explaining partial-update semantics ("what you leave out stays as it was"), the external side effect (the existing link picks up the new names, nothing is resent), and the failure condition once payment has occurred. No contradiction with the declared idempotent/destructive hints — correcting a name is naturally idempotent, which matches.

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?

One tight paragraph, front-loaded with the eligibility condition before the mechanics, and every sentence carries a distinct obligation. The inline example substitutes for several sentences of explanation.

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 still covers outcome behavior (the link reopens with new names) but never says what the call itself returns — e.g. an updated task/booking object — which an agent may need for follow-up steps. Otherwise complete for a mutation on a nested-object schema.

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?

Adds real meaning beyond the 67%-covered schema: a concrete positional payload example, the passport-name formatting rule, and the "give only what changes" contract that makes the array partial rather than a full replacement. It does not discuss leadTraveller at all, so a meaningful third of the parameter surface is left entirely to the schema description.

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?

Specific verb and resource ("correct who is travelling on a booking") plus an explicit precondition ("a booking the traveller has not paid for yet"). It names the fields it touches (name, date of birth), which separates it cleanly from siblings like book_trip, change_package_flight, and resend_link.

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?

Gives both directions of the routing decision: use this before payment is made, and it is "refused once the traveller has paid" — at which point names are changed with the airline via Vuelo support. It also pre-empts the obvious wrong sibling by noting the link already sent reflects the change and nothing is resent.

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