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

Beyond the readOnly/openWorld annotations, the description discloses a rich behavioral profile: it is free, performs no wallet connection, no external fetch, no signature verification, and no settlement, and it is limited to exact EVM profile checks. This is precisely the kind of side-effect disclosure an agent needs.

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 dense sentences, front-loaded with the core action and cost ('Free inspection') and followed by exclusions. No filler, though the negative-capability sentence is a long list that could be tightened.

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 nested-object, zero-required-param tool, the description covers safety and scope well, and no output schema exists to offload return-value documentation. It does not state what a check returns (e.g., pass/fail or diagnostics), which is a minor remaining gap given the inspection framing.

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%, so the two parameters and the nested 'expected' fields are already fully documented. The description echoes the constraint concepts (network, asset, recipient, atomic budget) but adds no format or syntax detail beyond the schema, so the baseline 3 applies.

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 names a specific verb and resource: inspecting supplied x402 v1/v2 payment terms against the SDK schema and optional constraints. It is clearly a validation/check operation, distinct from the payment-making siblings. It stops short of explicitly naming a sibling like compare_payment_terms, so it is clear but not sibling-differentiating.

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?

It scopes usage with 'Exact EVM profile checks only' and 'Other profiles are explicitly untested,' which tells the agent when the tool is inapplicable. However, it gives no positive routing guidance against alternatives such as compare_payment_terms or test_payment, so usage is only implied.

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