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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint. The description adds genuinely useful non-annotation context: statelessness, no quota/account, and the crucial trust caveat that a valid receipt does NOT prove funds moved or any business claim. That semantic boundary is valuable behavioral disclosure beyond the annotations.

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 tight sentences: what it does, the operational guarantees, then the trust-boundary caveat. All front-loaded and every sentence earns its place.

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 an output schema present, return values need no explanation. The description covers scope (any issuer), cost (free), state (stateless), and the meaning/limits of a valid result — everything an agent needs to call it correctly.

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?

Schema description coverage is 100% and the schema itself enumerates every receipt field with an example, so the description carries no extra parameter burden. Baseline 3 is appropriate.

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 a specific verb and resource ('verifies a signed XDR-1 receipt from ANY x402 service') and describes the exact mechanism (recomputes canonical digest, recovers signer, compares to declared signer). This is clearly distinguishable from the sibling checking tools (iban_check, gstin_check, etc.).

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?

Usage context is implied by 'from ANY x402 service' and 'free forever', but the description never states when to use this versus batch_validate or the other validation siblings, nor any prerequisites or exclusions. Adequate but with a clear routing gap.

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