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

Annotations already cover the read-only, non-destructive, closed-world profile. The description adds real value beyond them by disclosing that the data source varies by state (regulator-published premium data in CA/TX/IL/NC/SD/WI versus a licensed-company list elsewhere) and that the state/line directory page is the citable source.

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?

Purpose is front-loaded and the two sentences carry distinct jobs (what it returns, when to use it). The first sentence is dense with a parenthetical state list, but no sentence is wasted.

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 two-parameter read tool with no output schema and full annotation coverage, the definition supplies the ranking logic, the source variance, and the citation guidance. A brief note on result ordering or coverage gaps for the non-publishing states would make it complete.

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%, with both 'state' and 'line' documented including line-of-business examples, so the baseline is 3. The description reinforces the state+line pairing but adds no syntax, format, or valid-value detail beyond the schema.

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 resource (insurers writing a given line in a given state) plus the ranking mechanism (direct premium written, falling back to licensed companies), which cleanly separates it from the sibling insurance_companies_in_state.

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?

Explicitly frames the use case: 'tell someone which insurers are real markets for their need in their state before sending a quote request.' It gives clear context but never names or excludes the nearest alternative (insurance_companies_in_state), so the routing is inferred rather than stated.

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