price_flight

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

With no annotations, the description carries the full burden and discloses important behavioral traits: the call costs $0.003 paid via x402, and it returns the merchant's artifact and payment receipt. 'Confirm' and 'before booking' imply no booking side effect. It does not explain hold times or failure refunds, but the core cost and return behavior are transparent.

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 three sentences, with the core purpose front-loaded. Every sentence earns its place: purpose, cost/payment method, and return values. No filler or redundant restatement of the tool name.

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 two-parameter tool with no output schema, the description adequately explains the return values (merchant artifact and payment receipt) and adds essential context (cost and payment rail). It could mention what happens if the offer is no longer available, but overall it provides enough to understand the tool's role in the flight-booking workflow.

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 baseline is 3. The description adds no information about the parameters beyond what the schema already provides (offerId from search_flights, rail override). The schema's own descriptions are sufficient, so the description neither hurts nor meaningfully enhances parameter understanding.

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 uses a specific verb ('Confirm') and clearly identifies the resource ('live price and availability of a specific flight offer') and the context ('before booking'). It is immediately distinguishable from sibling tools like search_flights, which finds offers rather than confirming a chosen one.

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 phrase 'before booking' clearly indicates when the tool should be used, and the instruction to use an 'offerId from search_flights' implies the preceding step. However, it does not explicitly name alternatives or state when not to use it, so it stops short of full usage differentiation.

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