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

The description discloses the cost ('x402-paid, $0.05') and the return categories (verified / needs_review / rejected / insufficient_evidence), which adds value beyond the annotations. Annotations already indicate idempotent and non-destructive behavior, so the description doesn't need to repeat those. It doesn't detail billing side effects beyond cost, but given the annotations cover safety, this is sufficient.

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 two sentences, front-loaded with the core purpose and cost, followed by a compact list of verification targets and outcome categories. Every phrase conveys relevant information, and there is no redundancy or filler. It is dense but well-organized for quick scanning.

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?

The description covers the core function, the types of artifacts, the checks performed, and the expected outcome values. An output schema exists, so the description doesn't need to explain return values in depth. Given the tool's complexity (12 parameters, nested objects), the description is sufficient for an agent to understand when and why to invoke it, though it doesn't elaborate on policy construction—which is covered by the schema.

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%, so the parameters are fully documented in the schema. The description adds context about artifact types (x402_challenge, x402_receipt, etc.), which aligns with the 'artifacts' parameter but doesn't introduce new meaning beyond the schema. The baseline of 3 is appropriate since the schema carries the parameter-level detail.

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 clearly states the tool's purpose: 'verify an agent-commerce evidence bundle before trusting a paid result'. It names a specific verb (verify) and resource (evidence bundle), lists concrete artifacts (x402 challenge/receipt/policy-decision/service-response), and mentions specific checks (endpoint/price binding, freshness, hashes), making it distinct from generic verification tools.

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 'before trusting a paid result' provides clear context on when to use the tool. It does not explicitly mention alternatives or exclusions, but the context is specific enough to guide an agent. No explicit comparison to sibling tools like assurance_verify, so it misses the 'when not to use' aspect, but the usage context is clear.

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