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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description still adds real context beyond that: it explains what the extras range represents, that unpriced extras and unchosen admin/card fees may appear, and that some costs rise at the airport.

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?

Front-loads the core purpose, then explains the fare-conditional behavior and the extras model in three dense sentences. Every sentence carries content, though the third sentence is somewhat list-heavy and could be tightened.

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 10-parameter domain tool with an output schema, the description supplies enough behavioral framing (what is returned, what may or may not be priced) for correct invocation. The one real gap is the absence of routing against the similar sibling `airline_fees`.

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 70%, and the description meaningfully groups the choice parameters (cabin bag, checked bag by kg, seat, priority, infants) as things the traveler selects for their party and trip, and clarifies `fare` as the whole-party total from an external search. It adds interpretation beyond the field-level descriptions, though it stays silent on `trip` and `currency`.

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 resource (true cost of a flight on one airline) and implies the computation is fare + extras. It is understandable on its own, but it never differentiates itself from the sibling `airline_fees`, which its mention of 'admin, card %' fees partially overlaps with, leaving the reader to infer the boundary.

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 describes the conditional behavior of `fare` (include it to get fare + extras, omit it to get extras alone), which is useful, but that is parameter behavior rather than when-to-use guidance. No sibling alternative is named and no explicit 'use this when / not when' routing is provided.

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