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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds useful behavioral context: it returns specific fields, covers over 1 million entities, and notes NLOD 2.0 licensing and no API key requirement. It doesn't mention pagination behavior beyond the schema's page/size parameters, but the annotations carry the main safety burden.

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?

The description is compact and front-loaded with the core purpose. Every sentence adds value: what it searches, how to filter, what it returns, scale, licensing, and access requirements. No fluff or repetition of schema details.

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?

The description is complete for a read-only search tool. It covers purpose, filters, return fields, scale, licensing, and access. The output schema exists, so return values are documented. Minor gap: it doesn't explicitly mention pagination defaults or that results are sorted, but the schema covers page/size and the description is otherwise thorough.

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 the schema already documents all parameters thoroughly. The description adds value by explaining the filter semantics (e.g., municipality 4-digit code, org form examples, NACE code examples) and noting that at least one filter is recommended. This goes beyond the schema's individual parameter descriptions.

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 clearly states the tool searches Norway's official business registry, names the specific filters (name, municipality, org form, NACE code), and lists the return fields. It distinguishes itself from sibling tools like brreg.registry.entity, brreg.registry.roles, and brreg.registry.sub_units by focusing on search across the registry.

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?

The description explains what filters to use and notes that at least one filter is recommended. It doesn't explicitly say when to use this tool versus the sibling brreg tools (entity, roles, sub_units), but the search-focused name and description make the use case clear. It also mentions no API key required, which is useful context.

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