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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description's closing 'Read-only' adds nothing. It does contribute real behavioral context beyond the annotations: that results are 'approved' dealers and that absent coverage the fallback is direct shipping, which affects how an agent interprets an empty result.

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?

Two tight, front-loaded sentences that earn their place; the scope and optional state filter lead. The trailing 'Read-only' clause is redundant with the annotations, a minor waste.

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 simple read-only lookup with one optional parameter, full schema coverage, and clear annotations, the description covers purpose, scope, and fallback behavior. With no output schema, it could say more about what a dealer record contains, but that gap is small.

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 optional parameter is fully documented (two-letter code or name, omit for all). The description adds only the nuance that a state match can be by 'located in or serving' it, which the schema does not state — a marginal but genuine addition. Baseline 3 applies.

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+resource (find approved Duffer dealers) and qualifies the resource precisely: shops that sell, offer local pickup, or install, optionally restricted to one US state. No sibling tool overlaps this lookup, so disambiguation is inherent.

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 useful operational context — the 'no dealer nearby' case routes to direct sales shipping to every state — but never states when to call this versus siblings or when to omit vs. supply state beyond what the schema already says ('Omit for every dealer'). Usage is implied rather than directed.

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