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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful context by enumerating what the lookup surfaces (legal form, industry, address, bankruptcy/winding-up), but says nothing about rate limits, authentication, or result 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?

A single front-loaded sentence with the verb and resource first, followed by lookup keys and output fields. The trailing colon list is slightly ambiguous about whether those are returned fields or searchable fields, but nothing 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?

For a simple, two-parameter, read-only lookup with no output schema, the description covers the purpose, both lookup keys, and the returned data categories. The remaining gap is that it never explains how it differs from find_business, which matters for correct tool selection.

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 both parameters are already documented, including the conditional 'if the organisation number is not known'. The description's 'by organisation number or name' simply mirrors the schema, adding no syntax or format detail beyond it.

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 (looks up) and resource (a Norwegian business in Enhetsregisteret) and names the two accepted lookup keys plus the returned field set. It does not, however, distinguish itself from the sibling find_business, which an agent would need to disambiguate between.

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?

There is no guidance on when to use this tool versus the near-identical sibling find_business, and no prerequisites or exclusions are stated. The only hint is that both an org number and a name can drive the lookup, which is parameter information rather than usage selection.

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