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

The description discloses a significant behavioral trait: the call costs $0.005 USDC and x402-aware clients can settle payment inside the tool call. This directly contradicts the readOnlyHint=true annotation, since settling USDC on Base or Solana is a state-changing side effect. The description and annotation conflict, so this dimension must score 1.

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 only three sentences and front-loads the price and core purpose before mentioning output and settlement. Every sentence carries useful information, though the first sentence is grammatically awkward ('Paid $0.005 USDC on Base or Solana selection...'), preventing a top score.

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 paid tool with no output schema, the description provides some necessary context: cost, input requirements, output type, and settlement mechanism. However, it does not explain what the 'compact execution-ready contract' contains, what the user needs to do to pay if not using an x402-aware client, or what happens if payment fails. This leaves meaningful gaps for an agent invoking the tool.

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 0%, so the description must compensate for the parameters. It does map both required params: specUrl is 'one public JSON OpenAPI spec' and goal is 'a stated goal'. However, it does not explain what makes a good goal, whether the spec URL must be publicly fetchable, or any additional constraints, so the parameter guidance is only partially helpful.

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 what the tool does: select the best operation from a public JSON OpenAPI spec for a stated goal. The resource is specific (one OpenAPI spec) and the verb/objective is explicit (selection of best operation), which also distinguishes it from all sibling tools, none of which target OpenAPI operation selection.

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 use case is implied: call this when you have a stated goal and a public JSON OpenAPI spec, and need the best operation selected. However, there is no explicit when-to-use versus alternatives, nor any exclusion criteria or mention of what to do if the spec is private or not JSON.

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