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

With no annotations, the description carries the full burden and does so well: it discloses the billing model, the exact error/not_found conditions, and the data-completeness caveats (legacy archive frozen 2026-05-14, status_source legacy_li, unlisted MOTUS changes, no independent broker count). It also explicitly frames output as a record, not a rating or recommendation.

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-loaded with the core question, then structured into input rules, return fields, and a trust caveat. It is dense and long, but each block (billing, returns, reliability) carries information an agent needs, with only minor verbosity.

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?

With no output schema, the description enumerates the returned fields in detail (authority flag, docket status/continuity, bond BMC-84/85 coverage metrics, event history, revocation/suspension flags, identity linkage) and adds reliability caveats. Nothing needed to interpret or trust the result is missing.

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 0% and the two parameters are mutually exclusive optional fields, so the description must compensate. It does: it specifies the accepted MC formats (MC123456, MC-123456, 123456), requires exactly one identifier, and defines the free not_found/error outcomes, though the usdot_number format is left implicit.

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 and resource: it answers whether a broker holds active broker authority and reports what FMCSA's record says around it. This is clearly distinguishable from sibling identity/safety tools (check_carrier_identity, get_safety_history) by its broker-authority focus.

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?

Gives clear input rules (exactly one of mc_number or usdot_number) and cost semantics (paid and always billed on a resolved carrier; free not_found; free error), which tells the agent when a call is worthwhile. It does not, however, name sibling alternatives or explicitly say when to prefer another tool over this one.

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