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

Annotations already mark the tool as read-only and open-world, and the description adds meaningful context: it is free, reads from a live manifest, and returns endpoint metadata. No contradiction with annotations is present.

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 compact, front-loaded with the most important facts (free, what it lists), and has no wasted words. 'Call first' is placed at the end yet still clearly actionable.

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 read-only catalog with no output schema, the description covers price, source, returned fields, and usage order. The primary call path is clear. The only notable omission is the semantics of the optional 'filter' parameter, but that does not prevent a correct unfiltered invocation.

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?

The only parameter, 'filter', has no schema description and is not mentioned in the tool description. With 0% schema description coverage, the description needed to explain what filtering applies to or what format is expected, but it does not. The parameter name provides a weak hint, but this is a real gap.

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 clear action ('List') and a precise resource: every Genesis402 endpoint with price, title, path, and parameters from the live x402 manifest. It also distinguishes the tool from its siblings by framing it as the catalog that precedes individual endpoint calls. The 'Call first' instruction reinforces its unique role.

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 explicitly says 'Call first', giving agents clear temporal guidance to invoke this tool before other Genesis402 endpoints. It does not explicitly enumerate when not to use it or name alternatives, but for a catalog tool 'Call first' is a strong and sufficient usage signal.

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