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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds real value beyond them: it enumerates the response contents (prices, durations, airlines, layovers, ranked route-search actions) and discloses child-age provider mapping and the infant lap-versus-seat policy that must be confirmed before booking.

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, front-loaded with purpose and output scope; the age-policy sentence is dense but each clause carries information relevant to correct invocation. No filler or redundancy.

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 no output schema, the description usefully summarizes the return payload, and the 11-parameter surface is fully documented in the schema. Missing only selection guidance against siblings like flight_route_lookup or flight_booking_link.

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 coverage is 100%, so the schema already documents all 11 parameters, including currency fallback ordering and the outbound_end_date calendar behavior. The description restates the child-age mapping that is already in the schema and adds no new parameter syntax or semantics, so the baseline of 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), resource (flight itineraries with prices), and scope (two airports on a date) plus the underlying provider (Google Flights). An agent can distinguish it from route-oriented siblings like flight_route_lookup or status-oriented ones like flight_status_for_segment, though no sibling is named explicitly.

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?

There is no when-to-use statement, no condition selecting this over flight_route_lookup/flight_booking_link, and no exclusions. The only guidance is an age-handling caveat ('confirm before booking'), which is a booking caveat rather than tool-selection guidance.

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