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

The description goes beyond the annotations (readOnlyHint=true) by detailing what it does NOT do: 'No wallet connection, external fetch, signature verification or settlement,' and notes that other profiles are untested. This adds significant behavioral context that an agent would need to avoid misuse. There is no contradiction: readOnlyHint aligns with the inspection-only nature.

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 concise and efficient: three sentences that front-load the primary function ('Free inspection...') and immediately clarify exclusions. Every sentence adds value: the first defines the action, the second clarifies scope and constraints, the third lists what is not done. No fluff or repetition.

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 that there is no output schema, the description explains the input structure (via schema) and the purpose clearly. For a read-only inspection tool with schema coverage, it does not need to explain return values, but it could have mentioned expected output format (e.g., validation result). However, since the tool is largely self-contained and safe, it is complete enough for correct invocation.

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 input schema already has detailed descriptions for both parameters ('expected' and 'challenge') and covers all parameters (100% coverage). The description adds meaning by clarifying the constraints (network, asset, etc.) and the read-only nature, but the schema itself is strong. Since coverage is 100%, the baseline is 3, and the description does not add substantial parameter-specific detail beyond what the schema provides.

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 a specific verb ('free inspection'), the resource ('supplied x402 v1/v2 payment terms'), and what it does (checks against the SDK schema and optional constraints). It distinguishes itself from siblings by specifying it is a read-only inspection, not a payment action, and notes that other profiles are untested.

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 implies when to use this tool: for read-only validation of payment terms without wallet connection or settlement. It lists constraints (network, asset, recipient, atomic budget) that guide usage. However, it does not explicitly state when not to use it or mention alternatives like 'test_payment' for actual payment testing, but the context is clear enough for an agent to infer.

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