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

With no annotations, the description carries the full burden and does well: it discloses the $0.003 USDC per-call price, the x402/Base payment mechanism, ranking methodology (proven demand, 30-day unique payers, repeat calls, scanner filtering), and that results include the cheapest proven alternative. It does not explicitly state read-only behavior, but this is strongly implied by 'Find' and there is no hint of mutation.

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 three tightly packed sentences: purpose first, return/ranking details second, payment information last. Every sentence adds value without repetition or 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 paid discovery tool with no annotations and no output schema, the description supplies the critical missing context: cost, payment chain, ranking methodology, and the nature of returned results. It could be slightly more complete by explicitly confirming the operation is read-only or describing the response shape, but overall it is sufficient to call the tool 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?

Schema description coverage is 100%, so the schema already explains q, limit, and minPayers. The description adds useful context about what 'proven demand' and '30-day unique payers' mean, which indirectly clarifies minPayers, but it does not directly explain parameter usage beyond what the schema provides.

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 verb and resource ('Find the best x402 endpoints') and scopes it to 'a task'. It is clearly different from sibling tools like tokenrisk_check or guard_check, though it does not explicitly name alternatives such as intel_benchmark.

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?

Usage is implied by 'for a task' and the ranking criteria, but there is no explicit when-to-use guidance or any statement about when not to use this versus siblings. An agent must infer the selection context.

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