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: it discloses the paid model and that exact-key misses are free, warns that all carrier_status values are returned and must be checked, explains the insurance_cancel_pending snapshot semantics and that days_to_cancel_effective counts from record_as_of, and flags the removed contact fields. This is unusually rich operational context.

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 purpose is front-loaded and nearly every sentence carries signal, but the removal history ('removed 2026-09-19, see schemas.CarrierProfile') and repeated insurance caveats add length. Dense and justified overall, with minor trimming 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?

For a six-parameter tool with no annotations and no output schema, the description covers payment, status semantics, cancel-field behavior, and per-claim return values. It relies on a schema reference for the full profile shape rather than enumerating the return payload, leaving a small gap.

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 0%, so the description must compensate, and it does: claimed_name is matched against legal_name OR dba_name, the address fields match physical_address and any subset may be supplied, and it explains the name_match/physical_address_match booleans and the null-for-unsupplied rule. This fully documents the ambiguous parameters.

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 opening sentence states a specific verb (look up), a singular resource (a carrier's current profile), and the exact key (USDOT number), which cleanly separates it from the plural sibling search_carriers. An agent can identify the tool's job without reading the schema.

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?

It gives strong context for the claimed_* fields (identity confirmation / catching double-brokering) but never states when to choose this tool over siblings like check_carrier_identity or screen_carrier_identity. Usage is implied rather than explicitly routed, so it lands at minimum-viable-plus.

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