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

Annotations already mark readOnlyHint=true and idempotentHint=true, and the description adds valuable behavioral context: multi-provider sourcing (Duffel + Travelpayouts), indicative pricing with a booking link, empty-list behavior for no routes, and the ground-transport exclusion. No contradictions with 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?

The description is well-structured and front-loaded with the core action, then details the return payload, provider coverage, usage guidance, and limitations. Every sentence adds information; no redundancy or fluff.

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?

Without an output schema, the description enumerates the returned fields, making the response format predictable. It covers use cases, alternatives, limitations, pricing caveats, and empty-list behavior, making it sufficiently complete for a search tool with a rich input schema.

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 the baseline is 3. The description does not add parameter-level detail beyond the schema; it mentions 'two places' and 'requested currency', but currency is not a schema parameter and no parameter semantics are clarified beyond what the schema already provides.

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 clearly states the tool 'Searches flights between two places' and enumerates the specific output fields (carrier, price, cabin class, duration, stops, times, deep-link). It explicitly distinguishes from sibling tools by directing users to departi_search_accommodation and departi_search_experiences for other needs.

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?

Provides explicit when-to-use guidance ('Use for "how do I get from A to B by air"'), names alternative tools for accommodation and experiences, and states a clear exclusion ('Ground/rail/bus is not offered through this tool'). This fully instructs the agent on tool selection.

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