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

With no annotations, the description carries the behavioral burden well: it discloses that the operation is unsigned, sends exactly the on-chain ETH price, and routes funds to the project treasury with no promise about their use. It also warns that aircraft cannot be parked in a garage, though it does not cover approval or failure mechanics.

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 dense and front-loaded, with the core action stated first. Every sentence adds useful routing, financial, or behavioral context without filler.

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 no-annotation, no-output-schema prepare tool, it covers the essential context: unsigned transaction, exact ETH amount, treasury destination, aircraft limitations, and the sibling alternative. The schema already handles wallet semantics like balance and allowance reads.

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 both parameters are already documented. The description reinforces the model restriction and points to vehicle_shop for ethPrice, but it adds little parameter-level detail beyond the schema.

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 and resource: prepare an unsigned aircraft purchase for ETH. It names the allowed models and explicitly distinguishes itself from prepare_vehicle_buy, which handles ground vehicles.

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?

Gives explicit routing: aircraft models 4 or 5 use this tool, while ground vehicles models 1 to 3 must use prepare_vehicle_buy. It also clarifies that ground vehicles are not sold for ETH, removing ambiguity.

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