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

Annotations only declare readOnlyHint and openWorldHint; the description adds real behavioral context beyond them: a mandatory $0.05 USDC per-call fee via x402 on Base mainnet, the exact failure mode (unpaid call returns a PaymentRequired challenge), and the retry contract (identical call with signed payload in _meta['x402/payment']). This is exactly the kind of cost/error/retry disclosure an agent needs before invoking a paid 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?

Three sentences, front-loaded with what the tool returns, followed by price and the payment retry contract. No filler, though the payment mechanics occupy a substantial share of the text while routing guidance is absent.

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 does enumerate the return content (default credential risk, exposed OT protocols with ports, hardening recommendations), and it fully covers the paid-invocation path. It omits anything about rate limits, result scoping, or failure modes other than payment, but is otherwise complete for a two-parameter lookup.

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 both vendor and model with examples. The description adds only the framing that lookup is by vendor and model, adding no syntax or format detail beyond the schema, so 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?

States a specific verb+resource combination ('Exposure data for OT devices by vendor and model') and scopes it to OT/industrial control devices via the vendor/model lookup, which the bare title alone would not convey. It does not explicitly name the sibling it is not (e.g. getAssetExposure or getVendorRisk), so it falls short of full sibling differentiation.

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?

No when-to-use or when-not-to-use guidance is given relative to the ~38 sibling exposure/risk tools. The only procedural instruction is the payment retry flow, which tells the agent how to pay but not when to choose this tool over getAssetExposure, getRiskExposure, or getVendorRisk.

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