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

Annotations cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower, yet the description still adds real behavioral detail: the 25-mile radius, that counts are computed within that radius, that verified entries carry a date checked, and that results are sorted verified-first. Not stated is pagination or result caps for the list.

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 core operation is front-loaded effectively in the opening clause, but the description then inlines the entire 40-value service enum, which is redundant with the schema and bloats the text. The example-query sentence earns its place; the enum dump does not.

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?

With no output schema, the description carries the burden of explaining returns and does so well: business count, verified count with date, most-named brands, and a verified-first list. An agent knows what it will get back, though pagination/limits on the list remain unspecified.

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% and the service enum is fully self-documenting, so baseline 3 applies. The description clarifies that 'service' accepts any town-page service and that the radius is fixed at 25 miles, but it also re-lists all ~40 enum values verbatim, which adds no meaning the schema does not already carry.

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 states a specific verb+resource — count businesses of one service within 25 miles, count verified ones, surface top brands, and return a list — which is a distinctly richer operation than a plain lookup. However, it never names or contrasts against the sibling find_pros, whose 'list of pros' output overlaps with this tool's final element, so sibling differentiation is left to inference.

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 concrete routing cues via example questions ('who fixes appliances in Covington, LA?') and a clear selection condition — use this 'when no ZIP is known'. That is a genuine when-to-use signal, but it stops short of naming the ZIP-based alternative or stating when to prefer find_pros instead.

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