search_flights

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

With no annotations, the description transparently discloses the paid nature of the call ($0.005 per call), payment method (USDC over x402), and that it returns the merchant's artifact and payment receipt. This provides key behavioral context beyond what schema offers, though it lacks details on authentication or error handling.

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 two sentences, front-loaded with the core purpose, then adds cost and return information. Every word earns its place, making it highly concise and well-structured.

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?

Given the tool's complexity (paid API, 7 parameters, no output schema), the description adequately covers return values by specifying the type of data returned (priced offers with airline, times, stops, fare basis) and the additional artifact/receipt. It lacks details on pagination or round-trip behavior, but schema covers the optional returnDate.

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?

The input schema has 100% coverage with descriptions for all parameters, so the baseline is 3. The description adds no extra parameter semantics 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 airports on a date, which is a specific verb+resource+scope. It distinguishes from siblings like price_flight by mentioning it returns priced offers with airline, times, stops, and fare basis, indicating a broader search function.

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 usage for flight searching but does not explicitly state when to use this tool versus alternatives like price_flight. No exclusions or alternative recommendations are provided, so usage guidance is only implied.

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