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

Annotations already declare the operation as read-only, idempotent, non-destructive, and open-world. The description adds useful behavioral context by emphasizing 'live', indicating that results reflect current external contract state and readiness rather than cached or static data. It does not contradict the annotations and gives the agent a better sense of what the tool actually does.

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, focused sentence with no filler. It front-loads the core behavior ('Check live x402 contract') and then lists the key result areas concisely, making it easy for an agent to parse quickly.

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 no-input, read-only tool, the description covers the main purpose and key evidence categories. It could add more detail about return format or what 'readiness' specifically entails, but given the low complexity and strong annotations, it is nearly complete.

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 input schema has zero parameters, so there is no parameter documentation burden on the description. With 100% schema coverage and no required inputs, the description has nothing to add about parameter semantics; the baseline of 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?

The description names a specific verb ('check') and a specific resource/domain ('live x402 contract, readiness, and settlement evidence'), which clearly distinguishes it from sibling tools like check_history, check_status, and verify_provider. It goes beyond the tautological title 'Check Payment' and tells the agent exactly what aspect of payment is being inspected.

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 when to use the tool: whenever the agent needs live payment contract, readiness, or settlement evidence. However, it does not explicitly state when not to use it or point to a specific alternative, so the usage guidance is implied rather than explicit.

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