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

The description adds substantial behavior beyond the annotations: it uses cached runtime readiness, performs no external health probe, no analysis/payment/tenant lookup, a successful status lookup can still report ready=false, and the snapshot does not guarantee a later call or prove payment settlement. These caveats meaningfully shape an agent's expectations and are not present in the readOnlyHint/idempotentHint/destructiveHint annotations. No contradiction.

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?

Although the description is six sentences, every sentence carries distinct information: purpose, parameter semantics, read-only/free behavior, the ready=false caveat, the staleness caveat, and the sibling alternative. The critical purpose is front-loaded and no sentence is 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?

For a zero-parameter status-check tool with an output schema present, the description covers all the contextual ground an agent needs: what is checked, when to call it, cost/safety implications, failure semantics (ready=false), non-guarantees, and routing to the sibling. Nothing material is missing.

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 tool takes zero parameters and the schema already shows an empty object, but the description reinforces this by stating 'Takes empty arguments {}; no receipt, credentials or payment metadata.' This goes beyond the schema by ruling out implicit or hidden arguments, which is valuable for an agent deciding whether the tool requires setup before invocation.

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 opens with a specific verb and resource: 'Check receipt-service availability, configured USDC price/network, supported inputs, size limits, retention and exact-retry policy.' It explicitly distinguishes this from siblings by naming analyze_receipt (the paid call this status check precedes) and get_receipt_example (the alternative for inspecting a fixed sample). An agent can immediately understand what this tool is and what it is not.

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 states exactly when to use the tool: 'before authorizing a paid analyze_receipt call', and adds the operational guidance 'wait until ready before starting paid work.' It also provides the sibling alternative get_receipt_example for when a fixed sample result is needed instead. The when-to-use and when-not-to-use context is explicit and actionable.

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