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

No annotations are present, so the description carries the burden—and it does well. It discloses that this is a live FMCSA lookup, that the tool returns an x402 URL rather than performing payment directly, that the cost is $0.1 USDC on Base, and that calling the tool itself is free. It could add details like response content or failure modes, but the core behavior is transparent.

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 compact and information-dense, covering purpose, use case, cost, and return flow in a few sentences. The opening phrase repeats the title somewhat, but the rest adds real value. It is front-loaded and easy to scan.

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 one-parameter tool with no output schema, the description is nearly complete: it explains what the tool does, who uses it, why, what it costs, and what it returns. It does not fully specify the output structure or define 'plain flags,' but those gaps are minor for agent selection and invocation.

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 the only parameter 'mc' already has a clear description: 'MC/docket number (required).' The description repeats 'MC/docket number' but adds no extra format guidance such as whether the number needs leading letters or digits only. Since the schema fully documents the parameter, a baseline 3 is appropriate.

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 uses a specific verb ('check') and resource ('US freight broker authority'), states the exact regulatory source (FMCSA), and clarifies the purpose with 'Is this broker real and allowed to arrange freight?' It distinguishes itself from the sibling check_carrier_authority by explicitly targeting brokers rather than carriers.

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?

The description gives clear context: 'The check a carrier or factoring agent runs before accepting a load from an unknown broker.' It does not explicitly name alternatives or say when not to use this tool, but the intended scenario is clear enough for an agent to route appropriately.

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