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

Annotations already cover readOnly/openWorld/non-destructive. The description adds valuable non-annotation context: live federal data, plain risk flags, the $0.1 USDC fee on Base, the x402 payment flow (402 → PAYMENT-SIGNATURE → delivery), and clarifies the tool itself is free while payment occurs downstream. That payment mechanics disclosure is genuinely useful, though retry/timeout behavior is not covered.

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-loads purpose, then data fields, then the audience/use case, then pricing and payment flow. Dense but each sentence carries information. Slightly overloaded by the payment-flow sentence, which is layered but relevant.

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?

For a read-only, no-output-schema lookup, the description covers purpose, returned data, trigger context, and the payment/consumption flow — the missing piece an agent would otherwise be confused about (that the tool returns a payable URL rather than the data itself). Complete for its complexity.

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 describes both mc and dot as alternative identifiers, so the schema carries this. The description adds no parameter detail beyond what the schema states. Baseline 3.

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 (federal record lookup), a specific resource (US motor carrier via FMCSA), and enumerates the returned fields (legal name, operating status, authority, safety rating, fleet size, crash/inspection summary). It's clearly distinguishable from the nearest sibling check_broker_authority (broker vs carrier) and check_carrier_basics.

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?

Names the trigger context explicitly: 'the check a freight-broker or dispatch agent runs before tendering a load.' It doesn't say when not to use it or name check_carrier_basics/check_broker_authority as alternatives, but the use case is concrete.

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