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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely behavioral detail beyond them: the counting is scoped to a 25-mile radius around each town, results are sorted most-first, and the trade defaults rather than being required. It does not say how the coverage boundary ("the directory covers") affects results.

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 sentences, zero filler, with the substantive scoping (state, trade count, radius, ordering) front-loaded and the routing guidance second. Slightly dense as a single opening sentence, but nothing needs cutting.

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 does the work of sketching return values — town plus business count, sorted descending. For a 3-parameter read-only tool with full schema coverage that is sufficient, though it leaves the response shape (field names, whether zero-count towns appear) implicit.

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%, so state, trade, and limit are already documented including their defaults. The description restates the trade default and repeats the 25-mile notion rather than adding format or edge-case semantics. Baseline 3 applies when the schema carries the parameter burden.

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 names a specific resource (towns in one U.S. state) and qualifies it with the directory's coverage, a trade filter with a stated default (appliance repair), a 25-mile radius, and descending ordering. An agent can distinguish this from get_town_summary or find_pros without inspecting 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?

"Use it to pick a town for find_pros or get_town_summary" gives explicit downstream routing, making this a discovery entry point feeding two named siblings. It stops short of saying when *not* to use it, or what to do if the state has no covered towns.

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