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

With no annotations, the description carries the full burden and does so fairly well: it discloses the output shape (resource URL, method, price, networks, seller, 30-day payers/calls, buyers, wash/quality flags, score, as_of), the fairness rule ("Same rules for every seller"), and the cost of the call itself ($0.009 USDC). It omits auth requirements, rate limits, and latency/pagination behavior, which keeps it short of a 5.

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-loaded with the usage condition, then inputs, then a structured output field list, then a concrete example and price. Dense but nearly every clause carries information; the input list slightly duplicates the schema, which is the only mild waste.

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 discovery tool with no output schema and no annotations, the description compensates well by enumerating the returned fields and disclosing per-call cost. The main residual gap is the unmentioned include_flagged parameter and any note on result freshness or ranking determinism beyond "score" and "index as_of."

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 the schema already documents all five parameters, including include_flagged. The description restates q, max_price, network and limit but adds little syntax or format detail beyond the schema, and it omits include_flagged entirely. Baseline 3 is appropriate when structured fields do the heavy lifting.

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 opens with a specific verb-and-resource pairing: pick/rank paid x402 API endpoints for a task. It is readily distinguishable from siblings like web_metadata or site_profile, which operate in different domains. An agent can tell exactly what this tool returns without reading 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?

"Use when an agent must pick a paid x402 API for a task" states a clear triggering context, and the worked example (?q=base+token+honeypot+check&max_price=0.02) shows a concrete invocation. It does not name explicit alternatives or exclusions, but the sibling set is far enough away that this is a minor gap.

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