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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds that results carry return-trip EUR prices, the usual route price, a booking link, and a last-checked freshness timestamp, but with an output schema already present this return-content detail is largely redundant, and no rate limits or freshness caveats beyond 'last checked' are given.

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?

Two sentences, zero waste: purpose and scope first, return-content summary second. Front-loaded and appropriately sized for a search 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 an output schema handling return values, 100% schema coverage on all 7 params, and annotations covering safety, the description supplies enough to call the tool correctly. The only shortfall is the missing contrast with the two sibling tools, which an agent would need to resolve selection.

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 every parameter is already documented in the schema including the origin default of LUX and the 'any' option. The description only echoes the Luxembourg default and adds no syntax or constraint meaning 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 (Search) and resource (flight deals) plus scope: Luxembourg by default or nearby airports. This is clear and actionable, but it never names or contrasts with the siblings get_deal and list_destinations, so the agent must infer the boundary between searching vs fetching a single deal vs listing destinations.

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?

The description implies when to use it by describing 'current flight deals' from a default origin, but there is no explicit when-to-use, when-not-to-use, or alternative-tool guidance. Given get_deal and list_destinations sit alongside it, the absence of routing cues is a real gap.

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