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

No annotations are provided, so the description carries the burden of behavioral disclosure. It describes the output as a 'full safety + contact profile' but does not explicitly state that this is a read-only operation, nor does it mention any side effects, rate limits, or authentication requirements. Given the simplicity of a lookup tool, the description is acceptable but could be more transparent about the read-only nature.

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, clear sentence that front-loads the core functionality ('Full safety + contact profile') and lists key return fields. No unnecessary words.

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 tool has one parameter and no output schema. The description lists what fields are returned (identity, fleet, authority status, etc.) but does not specify the return structure (e.g., JSON object) or whether it returns a single result. Given the context of sibling tools and the lack of output schema, the description is functional but could be more precise about the output format.

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?

The schema covers 100% of parameters (the 'dot' field is described as 'USDOT number'). The description merely restates 'by USDOT number' without adding format, validation rules, or examples. Since baseline is 3 when schema coverage is high, this 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 clearly states the tool's purpose: retrieving a full safety and contact profile for a single carrier by USDOT number. It lists specific fields (identity, fleet, authority status, etc.), and the verb 'lookup' is implied. This differentiates it from siblings like carrier_risk_lookup (risk-focused) and safety_screen (screening), which have narrower scopes.

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 provides no explicit guidance on when to use this tool versus alternatives such as 'carrier_risk_lookup' or 'safety_screen'. It does not mention prerequisites, edge cases, or when not to use it. The only usage hint is that it requires a USDOT number, which is already in the schema.

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