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

Annotations already cover read-only/idempotent/open-world, so the bar is lower, and the description adds genuinely useful context beyond them: x402 pricing (0.01 USDC per successful call, free on error) and the caveat that sole proprietorship locations lack name/street address. It stops short of describing pagination limits or response shape.

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: what is returned, the data caveat, then the cost model. The resource definition is front-loaded with no redundant restatement of the title.

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 compensates by enumerating the returned fields, plus pricing and a data-completeness caveat. Pagination behavior is delegated to the schema, leaving only minor gaps such as empty-result handling.

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 orgnr format (9-digit, mod-11) and the page/size defaults are already documented. The description adds no pagination or identifier semantics of its own, making the baseline 3 correct.

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+resource: registered business locations (sub-units/underenheter) of a Norwegian company, and enumerates the returned fields. The 'sub-units, underenheter' framing implicitly separates it from get_company, which returns the parent entity.

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?

Usage is implied by the required orgnr and the resource described, but there is no explicit 'when to use this vs get_company / addresses_near' guidance or stated prerequisites. It never names a sibling tool.

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