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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered and the description needn't repeat it. What the description adds is the shape of the answer — per-country company types and document naming conventions — which genuinely helps an agent decide whether this answers the user's question. It says nothing about coverage gaps (e.g. what happens if a country is unsupported), which would be the useful extra for a closed-world lookup.

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, no filler, and the return-content sentence leads before the usage cue. The middle clause about registries is slightly dense but every part of it maps to something the tool returns, so little is wasted.

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?

There is no output schema, so the description must carry the return contract, and it does so at a high level but not exhaustively — it never mentions the country-code format, country coverage, or the failure mode for an unrecognised country. For a simple one-parameter lookup that is close to adequate, but the input-format omission is a real gap.

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 0% and the single required parameter is constrained by a regex (^[A-Z]{2}$) that is nowhere explained. The description says only 'a business in a country', which does not tell the agent that an ISO 3166-1 alpha-2 uppercase code is required — the exact thing most likely to cause a failed call. With low schema coverage the description should have compensated and does not.

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 concrete resource (business sign-up requirements per country) and even enumerates the payload: recognised company types and the registry's names for standard documents. That is far more specific than a restatement of the title. It stops short of a 5 because it never contrasts itself with the closest siblings, get_supported_countries and list_legal_documents, which an agent could plausibly confuse it with.

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 when a business owner asks what they need to get started" gives a real, actionable trigger tied to a user intent rather than a vague 'use for retrieving data'. No exclusion or negative case is stated (e.g. when to prefer list_legal_documents), which keeps it below 5.

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