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

With no annotations, the description fully discloses behavior: it probes the live endpoint for an x402 challenge, parses the agent's openapi.json, verifies price matching, and checks ledger response keys against a match_score threshold. It also clearly states zero cost and unpaid probes, so agents understand there is no payment side effect.

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 but every clause adds operational detail: the three proof sides, verdict values, input behavior, and cost. It is front-loaded with the key differentiator ('FREE' three-side proof) and contains no 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 tool with one optional parameter and an output schema present, the description covers input behavior, return verdicts, and cost implications. An agent has everything needed to invoke it correctly.

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?

Despite 0% schema description coverage, the single slug parameter is fully explained: pass an agent slug to prove one agent, or leave it empty for the full board with a summary. A concrete example is included.

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 states a specific deliverable: a three-side capability proof for AgentPayStore marketplace listings, with LIVE, SPEC, and LEDGER checks explicitly defined. This clearly distinguishes it from sibling payment-proof and x402 tools by resource type and scope.

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?

It gives clear context for when to use the tool—free proof of AgentPayStore listings, with an optional slug to prove one agent or empty input for the full board. It does not explicitly name alternatives or state when not to use it, but the use case is well scoped.

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