blackwall-x402-guardrail

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

With no annotations provided, the description carries full weight. It openly discloses critical behaviors: no custody, signed receipt, fee threshold, and data sources. It does not describe challenges in detail, but the transparency is strong for a lightweight 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 compact, deliverable, and front-loaded with the core verdict concept. It wastes no words and packs in essential details (receipt, free threshold, no custody) in two concise sentences.

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?

The tool has 8 parameters and no output schema, but the description covers the return value (verdict and receipt) and the key behavioral context (free under $10, otherwise challenge). Some return-format specifics are missing, but what's provided is sufficient for safe usage.

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 covers 100% of parameters, setting baseline at 3. The description adds meaning by explaining how parameters feed into the verdict (settlement reputation, price-anomaly) and the threshold behavior, which helps interpret values like amount and context beyond the schema 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 defines the tool as a payment forecast returning a GO/HOLD/STOP verdict based on reputation, price anomaly, and sanctions. It specifies the resource (payment decision) and the output (verdict with signed receipt), going far beyond the name 'forecast_payment'.

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 provides a clear 'when' by noting it's a pre-signature verdict, and a clear 'what-not' with 'Verdict only; never takes custody.' However, no explicit alternatives are mentioned (sibling tools is empty), so it stops short of a full 5.

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