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

No annotations are provided, so the description carries the full burden. It openly discloses the unpaid probe methodology, that it reflects an outside buyer view, that it says nothing about seller revenue, and that it is free and unauthenticated. This is thorough and honest behavioral disclosure.

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 somewhat long but information-dense and front-loaded with the core promise. Each paragraph earns its place: output, usage timing, parameter, and access caveats. A little marketing phrasing could be trimmed, but the structure supports agent decision-making.

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, the description is complete: it covers purpose, output fields, when to use it, parameter behavior, authentication requirements, and limitations. An agent has enough context to invoke it appropriately.

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 explain min_score, and it does: 'min_score filters to endpoints at or above a score.' It connects min_score to the 0-100 buyer-readiness score, though it does not explicitly state a valid numeric range for the parameter itself.

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, action-oriented framing: 'Find x402 endpoints you can actually pay right now' and lists the concrete returned fields (price, network, payTo, buyer-readiness score, buyer_notes). It is clearly distinct from siblings like check_x402_endpoint because it addresses the whole market rather than a single endpoint.

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 description gives a clear usage context: 'Use it before spending a research budget on a directory' and explains why most listed endpoints are no longer live. It does not explicitly name alternatives or state when not to use it, so it stops just short of full when/when-not guidance.

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