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

Despite annotations already declaring the read-only/open-world profile, the description adds substantial behavior beyond them: per-call pricing, the x402/MPP payment channel, that an empty result is still a paid 200, the 10-carrier cap, and data provenance (Motus vs legacy frozen 2026-05-14). This is exactly the kind of non-obvious cost and result semantics an agent needs before invoking.

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?

A single densely-packed paragraph where every clause carries information, with payment terms front-loaded (arguably an odd lead, but high-value). It is efficient, though the long run-on return-field list pushes toward density rather than crisp structure.

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?

An output schema exists, so the description needn't explain returns, yet it still enumerates result fields (status, OOS, authority, insurance, fleet size) somewhat redundantly. Combined with cost and caveat disclosure, the definition is essentially complete for calling, with minor overlap against structured output.

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 67%, and the description clarifies identifier formats (USDOT number, MC/MX/FF docket, exact company name with no partial match) and that identity resolution is FMCSA-sourced. It adds real meaning over the schema, though it does not restate the mutual-exclusivity constraint ('exactly one of') that lives in the schema text.

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 states a specific verb+resource (US motor carrier lookup) and enumerates the exact identifiers accepted (USDOT, MC/MX/FF docket, exact company name) via FMCSA. It is clearly distinguishable from sibling lookups like entity_lookup, license_search, and nonprofit_verify, which target different entity types.

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?

Usage context is implied ('Not a determination: verify with FMCSA before dispatch') but the description never names an alternative tool or states when another sibling should be used instead. The 10-carrier cap and empty-200 behavior hint at intended scope, but there is no explicit when-to-use/when-not guidance against alternatives.

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