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

The description adds substantial behavioral context beyond the annotations: it discloses the ranking criteria (returning paying wallets, 402 response, price, uptime), the result fields (price, networks, method, re-check links), and the cost behavior ('No match is never charged'). This is exactly the kind of detail an agent needs to understand the tool's behavior.

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 a single, front-loaded paragraph that covers purpose, ranking, result contents, and cost. It is slightly dense but every sentence contributes useful information; no obvious 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 read-only search tool with no output schema but rich annotations and full parameter descriptions, the description provides everything needed: what it returns, how it ranks, what each result contains, and the 'no match' cost caveat. An agent can call it correctly without further docs.

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 100%, so all parameters are already documented. The description does not add any parameter-specific meaning beyond what the schema provides (e.g., it doesn't explain 'sort' or 'include_down' further). With schema doing the heavy lifting, the baseline 3 is appropriate.

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 it returns x402 endpoints based on a plain-language need, with verb 'get' and resource 'x402 endpoints'. It does not explicitly differentiate from siblings, but none of the sibling tools are directly comparable, so the purpose is still unambiguous.

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: 'Say what you need in plain words … and get the x402 endpoints that do it.' It implies when to use the tool, but it does not state any exclusions or point to alternatives, which prevents a 5.

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