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

Annotations only give readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds real value beyond that: the bag is irreversible (cannot be removed or moved to another passenger), a processing fee may apply, confirmation is on by default but toggleable, and it requires 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?

The purchase action and its irreversibility are front-loaded, and most sentences carry weight. The confirmation-default and API-key sentences read as slightly generic platform boilerplate, but they still convey actionable constraints.

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 write tool with no output schema, the description covers the flow, the irreversible side effect, fee caveat, confirmation policy, and auth requirement. It omits any indication of the response, though no output schema exists to rely on, keeping this just short of complete.

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 schema already documents that trip_id is a booking number from list_trips and bag_option_id comes from get_baggage_options. The description reinforces the sourcing but adds no syntax or formatting detail beyond the schema, so 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 ('Adds one bag option to the booking') and explicitly ties it to the sibling tool get_baggage_options. An agent can distinguish this from kiwi-com_get_baggage_options 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?

Makes the workflow explicit: buy from get_baggage_options at the price shown there, and confirm with the user before each call since it reaches other people. It does not spell out when NOT to use it or list other alternatives, so it falls short of a 5.

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