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

Annotations only declare readOnlyHint=true, and the description usefully adds the paid-call price ($0.004 via x402), the transport (POST to a specific endpoint), and the shape of what comes back. It does not cover failure modes, payment/auth flow, or rate limits, so it adds value without fully discharging the behavioral burden.

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?

Two compact sentences carry purpose, price, endpoint, and the return fields with no filler. The endpoint URL is long but is genuinely load-bearing information for invoking the paid service.

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?

With no output schema, the description compensates by enumerating the result fields (verdict, score, categories, matched spans, obfuscation tricks, recommendation). It stops short of explaining error handling or what happens when payment is not prearranged, which matters for a paid remote call.

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% and there is a single required parameter whose meaning is already documented as 'Agent-bound text to classify'. The description's 'POST {text}' restates the parameter without adding format, length, or content guidance.

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: a prompt-injection check that classifies agent-bound text. It is clearly distinguishable from siblings like url-safety and x402-health by subject matter, though it never explicitly contrasts itself with them.

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?

There is no guidance on when to run this check versus url-safety, or on preconditions such as needing an x402 payment setup. The agent must infer usage entirely from the name and the schema's 'Agent-bound text to classify' note.

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