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

Annotations already establish the safe read-only profile (readOnlyHint=true, destructiveHint=false), so the bar is lower. The description adds real value beyond them: it discloses an auth requirement (Cotlet API key with app access) and enumerates the returned fields (booking number, route, departure, passenger count, documents_missing), which is what an agent needs since no output schema exists.

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?

The purpose is front-loaded, but the content is repeated almost verbatim: 'booking number, route, dates... whether travel documents are missing' then again 'booking number, route, departure, passenger count and documents_missing'. Two of the four sentences are redundant, wasting space on a short tool.

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 correctly compensates by listing the returned fields, and it surfaces the auth prerequisite. Combined with the annotations covering safety, an agent has enough to invoke it; the only gap is the absence of explicit routing versus kiwi-com_get_trip.

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% and the single 'when' parameter has an enum with its own default documented in-schema. The description adds nothing about the when filter (upcoming/past/all), so the baseline 3 is appropriate when the schema does all the work.

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?

The description states a specific verb and resource ('Trips on your account' / 'Returns the trips on your account') and clarifies scope via 'on your account'. However it never explicitly distinguishes itself from the sibling kiwi-com_get_trip, so an agent must infer the list-vs-single boundary on its own.

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 gives a forward-looking hint ('Use trip_id in every other trip tool') and a prerequisite ('Needs the user's Cotlet API key with access to this app'), which implies usage. But it never says when to use this list tool instead of get_trip, nor any when-not condition, so guidance remains implied rather than explicit.

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