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

Goes well beyond the readOnly/openWorld/destructive annotations by disclosing cost ($0.03 USDC on Base), the payment protocol (x402: 402 → PAYMENT-SIGNATURE → delivery), and clarifying that invoking the tool itself is free while payment occurs against the returned URL. That economic and side-effect context is exactly what annotations cannot convey and prevents an agent from treating this as a free direct data call.

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?

Front-loaded with the definition and field list, then pricing and protocol mechanics. Dense but nearly every clause carries information; the em-dash field enumeration is efficient. The payment flow sentence could be tightened but nothing is filler.

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 exists, so the description correctly carries the return burden by listing the fields and clarifying that the immediate return is an x402 URL rather than the carrier record itself. Failure modes (invalid MC/DOT, carrier not found) are unaddressed, which is the main remaining gap.

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 both parameters (mc, dot) are documented as interchangeable identifiers with the 'this or dot required' constraint already stated in the schema. The description adds nothing about identifier formats or precedence, so the 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 and resource ('Live federal FMCSA record for a US motor carrier') and enumerates the returned fields — legal name, operating status, authority, safety rating, fleet size, crash/inspection summary, risk flags. An agent knows exactly what it gets. It does not, however, distinguish itself from close siblings check_carrier_basics or vet_load, leaving overlap unresolved.

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?

Provides a usage trigger — 'the check a freight-broker or dispatch agent runs before tendering a load' — which is real context. But it names no alternatives (check_carrier_basics, check_broker_authority, vet_load) and gives no exclusion or prerequisite guidance, so the agent must infer which of several near-identical vetting tools to pick.

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