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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), and the description layers on non-obvious behavior: in-season plans sort first, and each summary carries dayCount/stopCount. The version caveat ('before 2026-09-28 stopCount held the day count') is the kind of data-format quirk an agent could never infer from schema or annotations.

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 usage trigger, then scope, then ordering, then return-shape caveats, then exclusions. Every sentence carries distinct information; nothing is repeated from the schema or annotations.

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 an output schema present, the description needn't document return values, and it still flags the one field whose historical meaning changed. Combined with annotations covering safety and idempotency, an agent has everything needed to select and call this tool correctly.

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 both parameters (city, audience) are fully documented there with format examples and an enum, so the baseline is 3. The description restates the browse dimensions ('by city and audience only') but adds no syntax or format detail beyond the schema.

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 opens with a specific verb and resource ('browse WonderKit's public multi-day itineraries and place guides') plus its scope ('for all cities or one city and audience'). It also distinguishes itself from the ranking sibling by noting it 'does not rank by a free-text description', so an agent can separate it from search_itineraries and get_itinerary without opening a 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?

It gives an explicit trigger ('Use this when someone wants to browse...') and clear exclusions ('does not rank by a free-text description', 'Does not book or edit a trip'), which routes the agent away from search_itineraries and the booking/planning siblings. It stops short of naming those alternatives outright, leaving a small step of inference.

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