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

With no annotations, the description carries the behavioral burden and does a good job: it lists the checks performed and the allow/review/block verdicts. It does not explicitly state that no payment is executed, but 'pre-payment guard' strongly implies a non-executing safety check.

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 tight sentences with no filler. The core function is front-loaded, the checks are summarized, the output verdict is stated, and the sibling tool reference is placed at the end.

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 7 parameters and no output schema, the description covers the main behavior and the verdict type. It could be more explicit about the return shape or the exact conditions for block, but the essential decision-making context is present and the sibling routing is included.

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 baseline is 3. The description adds semantic grouping: 'EVM payTo format' maps to pay_to, 'Base network' to network, 'amount validity' to amount_usd, and 'recipient/network/price changes' to the expected_* parameters. This clarifies how the optional expected parameters relate to the tool's purpose.

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 states a specific purpose: a pre-payment consistency guard that checks HTTPS destination, EVM payTo format, Base network, amount validity, and changes against caller expectations. It clearly distinguishes itself from vendor_preflight by naming what it does and what it does not cover.

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 explicitly routes agents to vendor_preflight for deep KYB, giving a clear alternative and the condition for choosing it. The 'pre-payment' and 'consistency guard' wording makes the intended use case evident.

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