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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds two things the annotations cannot: results are cached up to 10 minutes (so data may be stale) and the response is structured as raw checks followed by reasons and a signal summary. That is genuine added context for an agent reasoning about freshness.

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?

Three short sentences: cost/availability first, then what the response contains, then the caching caveat and the no-input constraint. Every clause carries information and the most decision-relevant facts are front-loaded.

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?

With no output schema, the description usefully enumerates the returned check fields and the reasons/summary layer, and it discloses caching and the absence of inputs. What remains unstated is auth or rate-limit requirements and an explicit routing hint versus payradar, which keeps it short of 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?

There are zero parameters, so the baseline is 4, and the description correctly confirms 'No inputs' so the agent knows no configuration or endpoint argument is accepted. Nothing further is needed for an empty object 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 names a concrete deliverable: a full Pay Radar example run against Agent Weather's own /v1/pulse/facilitator endpoint, enumerating the checks it performs (reachable, latency, tls, x402 shape, asset, payTo). The word 'example' plus the fixed endpoint distinguish it from the sibling payradar tool, though the description never names that sibling outright.

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?

'Free' and 'No inputs' imply this is a zero-config trial call, which is useful selection context, but there is no explicit statement of when to pick this over payradar or paycheck_demo. The agent must infer that this is for evaluating the response shape rather than checking its own endpoint.

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