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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the description's contribution is what the aggregation returns and that it deliberately omits contact details. It stops short of noting data-freshness, coverage limits, or how percentage denominators are computed.

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, front-loaded with the resource and metric list, then the usage example. Nothing is repeated from the title or schema and no sentence is filler.

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 return-value burden and does so by enumerating every reported metric and the exclusion of contact fields. Combined with annotations covering safety and the fully documented schema, an agent has everything needed to select and call it.

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%: the trade field already points to list_trades slugs and the location field already specifies US/Canada/Australia. The description's Ohio/plumbers example implicitly maps to the two parameters but adds no syntax, format, or matching behavior beyond the schema, so 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 and resource ('Aggregate statistics for an industry in a place') and enumerates exactly what is computed: counts, average rating, review totals, and per-field coverage percentages. The line 'No contact details' plus the market-sizing framing separates it from the sibling list/search tools that return records.

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 an explicit when-to-use condition with a concrete example ('how many plumbers are there in Ohio'), which anchors the tool to market-sizing questions. It does not name the alternative siblings (e.g., get_list_details) or state when-not to use it, so routing is implied rather than prescribed.

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