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

With no annotations, the description carries the burden for behavioral disclosure. It adds useful context: results are 'real, probed resource[s]' with a 'measured 402 Score' and the tool is 'Free.' However, it does not disclose potential limitations such as pagination, rate limits, or authentication requirements. It is a search operation, so mutation is not a concern, but the description could offer more on what happens during execution or response handling.

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 two sentences, with the first sentence stating the core purpose and the second adding quality and cost. It is front-loaded, concise, and every sentence adds value without redundancy.

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 simple search tool, the description provides adequate context: it specifies the source (Market402 verified index), the query type (capability), and result characteristics (real, probed, with 402 Score). It lacks an explicit output schema or return format description, but the absence of an output schema and the simplicity of a search operation make this acceptable. The description could mention pagination or error behavior, but it is reasonably complete for the tool's complexity.

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 0%, so the description must compensate. It explains the 'q' parameter by indicating it takes capabilities ('by capability') and gives examples ('ocr', 'market-data'). However, it does not explain the 'limit' parameter beyond its schema default. The description adds meaningful semantics for the primary parameter but is incomplete for the full parameter set.

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 the tool's function: 'Search the Market402 verified index of the whole x402 economy by capability.' It uses a specific verb ('Search') and a specific resource ('Market402 verified index'), with examples ('ocr', 'market-data') that make the purpose immediately clear. This distinguishes it from sibling tools, which are all specific extraction or enrichment operations.

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 implies the tool is for discovering resources by capability, which is a distinct use case from the sibling tools that perform targeted extraction or parsing. However, it does not explicitly mention when not to use this tool or name alternative tools. The context is clear enough for an agent to infer appropriate usage, but exclusions are absent.

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