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

Without annotations, the description carries the full burden. It discloses that the tool does not fetch endpoints, returns a structured verdict, and has a cost. It remains silent on error conditions, permissions, and side effects, but covers key behavioral traits sufficiently.

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 information-dense but well-structured, opening with the main purpose. It could be slightly more concise (e.g., 'per-entry scores...' details), but every sentence adds value. Front-loaded with key actions and constraints.

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?

Given 8 parameters and no output schema, the description explains parameter roles but lacks detail on the exact output format (beyond 'per-entry scores...'), error handling, and edge cases. The tool's complexity demands more thorough completeness for optimal agent use.

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 coverage is 100% (baseline 3). The description adds meaning by explaining that `paymentPayload` is an unsigned EIP-3009 authorization, `endpointUrl` is never fetched, and `selectedOptionIndex` scopes the verdict. This goes beyond the schema's generic descriptions.

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 action ('Vet an x402 counterparty before settling USDC'), resource (payment requirements and EIP-3009 authorization), and output (trust verdict). It is distinct from siblings like secure-code-review or secret-scan, which focus on code security, not trust evaluation.

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 specifies the primary use case (before settling USDC) and includes contextual clues like 'security; up to 200c/call' and 'No endpoint fetch'. However, it does not explicitly state when not to use the tool or mention alternative approaches, leaving some room for ambiguity.

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