Verify with a signed receipt (paid)

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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing price ($0.01), payment rail (x402, USDC on Base), the required environment credential (KYA_PRIVATE_KEY), the absence of the free daily limit, and the extra signed receipt in the response. These are exactly the cost, auth, and rate-limit facts an agent needs before invoking a paid endpoint.

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?

One dense sentence with the cost and payment prerequisites front-loaded and the differentiation from kya_verify second. No filler and nothing that fails to earn 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?

For a one-parameter verification tool it covers cost, prerequisite env var, rate-limit contrast, and the added return artifact (signed receipt), which substitutes for the missing output schema at a high level. It does not describe receipt format or payment-failure behavior, leaving a small gap.

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% for the single credential_id parameter, including format, pattern, and header context, so the schema already carries the semantics. The description adds no parameter detail beyond that, which is the baseline-3 case for a fully documented single param.

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+resource (verification via kya_verify_paid) and immediately differentiates from its closest sibling: 'Same answer as kya_verify, without the free daily limit, plus a signed receipt.' An agent can tell exactly what it gets versus the free variant without opening the schema.

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 phrase 'without the free daily limit' implies the selection condition (use when the free tier is exhausted or when a receipt is needed), and it explicitly names the alternative kya_verify. It stops short of an explicit 'use this when / not when' statement, so it is clear context rather than full routing guidance.

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