Find a paid service

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

The description adds substantial context beyond the annotations: ranking order, the meaning of paid_verified and latest_purchase_delivered, the warning not to pay when the latest purchase did not deliver, sample availability, and the caveat that results are dated evidence rather than guarantees. The annotations already declare read-only and non-destructive behavior, and the description does not contradict them.

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 dense paragraph with the core purpose front-loaded and no filler. Each sentence carries operational value: ranking, result fields, warning about failed paid purchases, relevance behavior, zero-result interpretation, and return detail.

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 an output schema and rich annotations, this definition is complete enough to call correctly. It covers scope, ranking, key result fields, safety warnings, query behavior, and return modes.

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 the schema already documents all eight parameters. The description still adds useful meaning by explaining that query relevance comes from plain-language need descriptions and that detail='full' returns every field, but most individual filter semantics remain in the schema.

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: 'Search paid x402 APIs and datasets by need.' It also describes ranking and result fields, which clearly separates discovery from sibling tools like get_service_details or resolve_endpoint without needing to name them.

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?

It clearly explains the search context, how query text drives relevance, and that zero results means no listing matches. It also implies detail='full' as an alternative to the summary return, but it does not explicitly name sibling tools or state when not to use this tool.

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