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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail beyond that: it 'resolves locations and dates,' limits results to 10 itineraries, and produces an 'interactive comparison with prices, schedules, stops, and booking links.' This goes well beyond what the annotations convey.

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 description is a single, front-loaded sentence with every clause earning its place. It states the core action first, then the key differentiators, then the concrete output. There is no filler, repetition, or unnecessary detail.

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 complex tool with 9 required parameters and a nested trips structure, the description provides the essential high-level behavior: live search, fuzzy input support, a 10-itinerary cap, and what the results contain. The rich input schema and output-schema presence carry the detailed contract, so the description is sufficient for selection and initial invocation, though it could mention example request shapes.

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 only 44%, and the description does not compensate for the undocumented parameters. The phrase 'vague or broad location names and flexible dates' loosely maps to the trips fields, but nothing explains search_type, passengers, cabins, max_price, max_stops, flight_duration, connecting_airports, or bags. With nine required parameters, this is a significant gap.

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 states a specific verb and resource: 'Search live public airfare.' It also adds a distinctive capability—handling 'vague or broad location names and flexible dates'—and clearly describes the output: 'up to 10 itineraries in an interactive comparison with prices, schedules, stops, and booking links.' This makes the tool's purpose unmistakable even without sibling tools.

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 gives clear context for when to use the tool: whenever a user needs live airfare search, especially with fuzzy locations or flexible dates. It does not explicitly state when not to use it or name alternatives, so it misses the top tier, but the absence of sibling tools makes the provided context reasonably complete.

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