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

Reveals a behavioral trait the annotations cannot convey: it makes outbound unpaid requests to candidate services, explaining why idempotentHint is false, and it asserts 'Never pays them,' confirming the read-only/no-spend profile. Pricing ($0.01 USDC) and free-trial status are also disclosed. Lacks detail on failure handling if few candidates answer.

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?

Front-loads the core differentiator in the first clause and keeps the pricing note brief. The tagline 'Plain-English job in, working services out' is slightly promotional but compact and does convey input/output shape.

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 6-parameter search tool with an output schema, the description covers purpose, verification behavior, cost, and availability, so an agent has what it needs. Return-value details are rightly deferred to the existing output 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 all six parameters (q, limit, network, maxPrice, minPayers, includeNovelty) are already documented in the schema. The description adds no additional parameter meaning beyond confirming it takes a plain-English job in, so baseline 3 applies.

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?

Names the sibling it derives from (x402/find) and states the specific differentiator: re-checking each top candidate with a live unpaid request and keeping only valid x402 price quotes. An agent can distinguish it from x402-find, x402-recommend, and x402-check without opening any schema.

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 contrast with /x402/find implies when to use this variant (you need currently-live, verified services rather than a cached shortlist), but it does not spell out an explicit when-not or a cost/latency tradeoff against the cheaper alternative. Clear context, no explicit exclusions.

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