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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely new behavior: results are grouped by country, the trade is normalized to English in the default listing, and country-filtered results switch to local trade wording with site names. That shape change per filter is real information the annotations cannot convey. Return format beyond this (field names, ordering) is not described, and there is no output schema.

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?

Three tight sentences with the core behavior front-loaded, followed by per-parameter guidance and a downstream-usage note. No filler, no redundancy with the title or annotations, and every clause carries actionable content.

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 two-optional-parameter read tool with no output schema, the description supplies enough: what is listed, how it is grouped, how each filter changes results, and how the output feeds other tools. What remains unstated is whether results are paginated or bounded and the exact per-site fields, which matters slightly given no output schema exists.

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%, so the baseline is 3, but the description goes beyond it by explaining the behavioral consequence of each parameter: country yields a single country with site names and the local trade word, trade performs a search. This tells an agent that the two parameters change not just filtering but output shape, which the schema alone does not reveal.

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 with scope: lists sites, one per trade-and-country pair, grouped by country, with the trade rendered in English. That is far more precise than the title restatement. It does not, however, name or distinguish itself from the siblings find_providers and get_service_info, so an agent must infer the boundary.

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 clear conditional guidance for both optional parameters: pass country for a single country with local trade wording, pass trade to search by trade. It also supplies workflow context with 'Use the site in the other tools,' establishing this as a prerequisite lookup step. It stops short of naming the alternative sibling tools or stating when not to use it.

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