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

Annotations already mark it read-only/idempotent/open-world; the description adds 'public' and 'reference only', clarifying that returned prices may not be live paywall values. This enriches the annotations with behavioral context, though it still omits output shape.

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?

Single sentence, front-loaded with the operation, then scoped with 'reference only' and the 402 caveat. No 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?

Given the zero-parameter signature and rich annotations, the description covers the tool's purpose and its key limitation. It could specify the exact return shape, but for a public reference-price lookup the essentials are present.

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?

With zero parameters and an empty input schema, there are no parameter semantic gaps for the description to fill. The baseline 4 applies.

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?

States precise verb 'Get' and resource 'public x402 list prices for lookup and scores', immediately distinguishing this reference-price tool from sibling query tools like connect_lookup and connect_scores_batch. The phrase 'reference only' adds scope clarity.

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?

Explicitly warns that live paywall amounts are not returned here ('live paywall amounts are in 402 responses'), telling the agent when not to rely on this tool. It does not explicitly name alternative tools, but the 402-response pointer gives clear routing context.

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