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

Beyond the annotations (readOnlyHint, idempotentHint), the description discloses additional behavioral traits: it returns a single document with a specific structure, the price is a floor not a flat price, and counts are cached server-side for a few hours from live inventory, explicitly avoiding stale marketing-page data. This adds significant transparency beyond the structured annotations.

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 description is front-loaded with the core purpose, then provides a compact yet detailed breakdown of the return format, field semantics, usage guidance, and caching behavior. Each sentence carries essential information; there is no fluff or redundancy. The structure is logical: what, return shape, field explanations, usage, and freshness.

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 tool with no input parameters and a rich output, the description is exceptionally complete. It covers the exact return structure, field meanings (including the nuance of price_from_cents), how to use it in a buyer journey, and even notes about data freshness. The presence of an output schema (mentioned in signals) is further complemented by the inline return example. Nothing an agent needs to call this correctly is missing.

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?

The tool has zero input parameters, so the baseline is 4. The description does not need to explain parameters, and it correctly focuses on the output structure. Since there are no parameters, the description cannot add value here, but it also does not miss anything.

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 description clearly states the tool's purpose: it returns ready-made lists for every live state × business type, with live counts and a starting price. It differentiates itself from siblings by explicitly contrasting with quote_list (full price ladder) and interpret_list (narrowing). The verb 'list' and resource 'starters' are specific, and the scope is unambiguous.

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?

The description provides explicit usage context: 'Show these to a buyer who has not said what they want yet, then narrow with interpret_list or your own filters and price the result with quote_list.' This tells the agent exactly when to use this tool and how it fits into a workflow, including an alternative (interpret_list for narrowing) and a follow-up (quote_list for pricing).

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