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

Annotations already declare this as a safe read operation, but the description adds important behavior beyond them: it costs 2 credits, tier-restricted plans are refused at no cost with tier_restricted naming the unlocking plan, and the caller should relay that rather than report absent data.

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 front-loaded with what the tool returns, then immediately covers lookup prerequisites, cost, cheaper alternatives, and refusal behavior. Every sentence adds actionable information with no wasted text.

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 single-parameter read tool with no output schema and annotations that already cover safety, the description supplies the remaining important context: cost, alternative tool routing, and tier-restriction handling. Nothing essential for correct invocation is missing.

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% and the single CVR parameter is already well documented with its 8-digit pattern. The description adds useful lookup semantics by stating that the tool is looked up by CVR number and that search_companies should be used first when only a name is known.

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 states a specific resource and result: companies owned by one Danish company, including the ownership band for each. It distinguishes itself from siblings by naming search_companies for name-only lookups and get_company for multi-section needs.

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?

It gives explicit when-to-use guidance: look up by CVR, use search_companies first when only a name is available, and use get_company with `sections` when the caller needs the profile or multiple sections. These alternatives and conditions are stated directly.

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