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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), and the description adds substantial context beyond them: the 48-hour pre-departure window, the empty-list behavior when the airline has no seat selection, the fallback (airline assigns seat at check-in at no cost), and the auth requirement for a Cotlet API key with app access.

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-loaded with the outcome and scoping constraint, then the practical caveats and auth note. Slightly long, with mild overlap between the opening sentence ('Seats you can pick on one flight...') and the second ('Returns the seat map Kiwi.com shows for one flight'), but nothing is wasted.

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 two-parameter read tool with full schema coverage and clear annotations, the description covers everything an agent needs: what it returns, when the selection window is open, what an empty result means, and the auth prerequisite. No output schema is needed since the return content is described in prose.

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 trip_id ('Booking number from list_trips') and flight_id ('Flight ID from get_trip') are already fully documented in the schema. The description adds no parameter-level detail 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 ('Get seat map' → returns the seat map Kiwi.com shows for one flight of a trip), and scopes it precisely to a single flight. An agent can distinguish it from the write-side sibling kiwi-com_select_seat, which acts on this map, without opening the 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?

Gives real usage context: seat selection is only open up to 48 hours before departure, and if the airline doesn't offer selection the list comes back empty. It never explicitly names an alternative tool or states 'call this before select_seat', so the routing guidance is 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.