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

With no annotations, the description carries full burden. It discloses latency (<200ms), checks performed (OFAC, mixer, overspend), and pricing. It lacks details on side effects, error handling, or response format, but covers key behavioral traits for a risk screening tool.

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 somewhat verbose, including pricing and marketing language (e.g., 'hosted spending guard an offline SDK cannot give'). It is front-loaded with core purpose but could be more concise.

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?

No output schema is provided, and the description only mentions the return type (ALLOW/REVIEW/BLOCK) without detailing response structure or error behavior. For a tool with 4 parameters, more completeness about output and edge cases would be beneficial.

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 schema already documents each parameter. The description reinforces the purpose of parameters (e.g., 'expected_price' for overspend detection) but adds minimal new semantic meaning beyond the schema.

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 function: a pre-payment risk firewall that validates recipient, amount, and chain before sending an x402 payment, returning ALLOW/REVIEW/BLOCK. It lists specific checks like OFAC blocklist and overspend prevention, making the purpose highly specific and distinct.

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 instructs to use this tool before sending an x402 payment. It mentions preventing overpaying or paying bad addresses but does not explicitly contrast with sibling tools or provide when-not-to-use scenarios. However, the sibling list shows no direct alternative, so the guidance is adequate.

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