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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds substantive context beyond that: which live data is pulled (operating authority, insurance on file, safety rating when available), that Canada returns guidance rather than a lookup, and that the output includes the official record URL for confirmation. It stops short of noting behavior for unmatched records or rate limits.

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 core purpose is front-loaded in the first clause, followed by jurisdiction specifics and a short usage sentence. The middle sentence is dense but each element (US sources, UK source, Canada fallback, return value) carries needed information; only minor tightening is possible.

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 carries the return-value burden and does so by naming the official record URL and the fields surfaced. Coverage of all three markets plus the pre-deposit usage motive makes it complete for a two-parameter, read-only lookup tool.

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 description coverage is 100%, so the two parameters are already fully documented, including the us/uk/ca enum meaning and the acceptable query identifiers. The description largely restates this scope by jurisdiction and adds little syntactic or edge-case detail, so the baseline of 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?

Names a specific verb and resource ('looks a moving company up in the official register') and scopes it by jurisdiction (FMCSA/USDOT/MC for the US, Companies House for the UK, guidance for Canada). It is clearly distinguishable from siblings like find_movers and get_mover_profile, which deal with discovery and profiles rather than official licence verification.

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 an explicit trigger: 'Use it before anyone pays a deposit or when a quote names a USDOT.' That is real when-to-use guidance tied to a decision point. It does not, however, contrast itself against nearby siblings such as get_mover_profile or find_movers, so the routing is clear but not exhaustive.

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