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

Annotations only declare it as a safe read (readOnlyHint, openWorldHint); the description adds non-obvious behavior no annotation conveys: results are ordered with paid placements first, flagged sponsored: true, and must be rendered as 'Sponsored' with the link passed through verbatim. This is exactly the kind of commercial/results-shaping context that annotations can't express.

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?

Three sentences, front-loaded with what the tool returns, then when to use it, then handling rules. Every sentence carries weight, though the country phrase slightly duplicates the schema.

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 read-only, open-world search with an output schema present, the return shape needn't be explained, and the description still adds the critical commercial-ordering and presentation contract. Nothing an agent needs to call and correctly render this tool is missing.

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 all three parameters (country, from, to) are already fully documented, including the 2-letter-code-or-English-name format. The description's 'for travellers from a country' restates the schema without adding format or edge-case meaning.

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?

It states a specific verb+resource: travel offers (stays, trips) from businesses constrained by a date range and origin country. The scope is sharper than the generic sibling names (find_long_weekends, start_planner), though it never explicitly contrasts itself against them.

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 concrete triggering situation ('when someone has dates for a break and asks where to go or what is on offer'), which is enough for an agent to pick this tool over a planning tool. It stops short of naming an alternative or an exclusion condition.

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