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

With no annotations, the description carries the transparency burden. It discloses that the tool is free, that it is a preview/assessment step before purchase, and enumerates the returned data categories. It does not explicitly state read-only behavior or potential error conditions, but the 'before purchasing' phrasing strongly implies a non-destructive, informational operation.

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 a single, dense sentence that front-loads the core purpose and enumerates useful output fields and use cases. Every clause earns its place, with no redundant or filler content.

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?

Given the simple one-parameter input and no output schema, the description sufficiently describes both the input context and return contents (USDOT, FMCSA name, class, counts, geo coverage). It also explains the business purpose, making it complete for an agent to select and invoke the tool appropriately.

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?

There is one parameter, `usdot`, and the schema already provides a clear description and example ('USDOT number, e.g. 054283') with 100% coverage. The tool description mentions USDOT as part of the output but adds no additional semantic meaning to the parameter beyond what the schema already supplies.

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 clearly identifies the tool as returning a commercial-carrier sighting profile with specific data fields (USDOT, carrier name, class, counts, geo coverage). It distinguishes itself from sibling tools by noting it is a free 'before purchasing' evaluation, which separates it from likely full-data tools like get_spotter_carrier.

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 explicitly states when to use the tool: before purchasing a carrier's sighting bundle, and for carrier_identity_verification or cargo_fraud_investigation. It provides clear context but does not mention when not to use it or explicitly name alternative tools, so it stops short of a 5.

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