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

The description explicitly mentions x402 settlement and a $0.05 per-call cost, and the parameter description instructs the caller to retry with a payment proof. This implies a financial side effect, which contradicts the readOnlyHint=true annotation. This is an annotation contradiction.

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 one compact sentence with the cost and core routing behavior front-loaded. The parenthetical 'MSS v2 Sovereign Router' adds some product specificity but is not fully explained, so it is not perfectly efficient.

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 description and parameter note explain the payment flow but do not clarify what request is being routed, what a successful call returns, or how the tool selects among registered providers. Without an output schema, these gaps make the actual invocation semantics underspecified.

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%, and the single payment parameter already has a rich description explaining EIP-3009 and the two-step payment flow. The main description adds little beyond the schema's own parameter semantics.

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 concrete action, 'Route across registered model providers,' and references the x402 settlement protocol, which gives a clear sense of what the tool does. It does not explicitly differentiate route from sibling tools like providers, and the 'MSS v2 Sovereign Router' phrase is unexplained jargon, so it falls short of a 5.

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 about when to use this tool versus its alternatives, such as providers or score. The payment-parameter description explains a retry flow, but that is procedural rather than a when-to-use-vs-sibling comparison.

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