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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds real behavioral context: results are limited to carriers already stored, matching is substring on legal/DBA names, and each call costs 1 lookup. It does not describe the result shape or what happens with zero matches, and 'already stored' is in mild tension with openWorldHint=true.

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?

Three short sentences, front-loaded with what the tool does, then the routing rule, then cost. No filler and every clause carries information the agent needs.

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 one-parameter read tool with full schema coverage and no output schema, this is nearly complete: scope, match semantics, result cap and cost are all present. Only the return fields / empty-result behavior are left to inference.

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 100% and the single parameter is required and documented, so the baseline is already met. The description nonetheless adds value the schema lacks: the match is a contains/substring test against legal or DBA names, not just 'company name'.

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 (find) plus resource (carriers already stored by CarrierVet), and narrows the matching rule to legal or DBA name substring search with a 25-result cap. It also names the sibling it is not (lookup_carrier), so the tool is distinguishable without opening any 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?

'Prefer lookup_carrier when you have a USDOT or MC number' gives an explicit alternative and the exact condition that selects it. Adding 'Costs 1 lookup' lets the agent weigh the call against budget, which is usage guidance beyond mere routing.

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