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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), yet the description adds real behavior: the cost is 1 credit and it is described as the cheapest call, and it explains the ophoert/ophoersDato trap for closed sole proprietorships. It stops short of error or rate-limit behavior, so it is strong rather than exhaustive.

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?

It is longer than typical but front-loads the return contents, then the interpretation caveat, then the routing and cost. Nearly every sentence carries decision-relevant information; the closing cost/get_company sentences are dense but not redundant.

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 must describe return values and does: name entries and status entries with from/to dates, founding date, company form, plus the ophoert/ophoersDato fields. Nothing an agent needs to call it or read the result correctly 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 coverage is 100% and there is a single CVR parameter, so baseline is 3. The description still adds meaning: the lookup key is the CVR, CVR survives a rename so old and current names are the same legal entity, and it redirects to search_companies 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?

States a precise verb-and-resource: every name and every status a Danish company has carried, with date ranges, founding date and company form. It explicitly distinguishes itself from the sibling get_company ('returns the whole profile') and names the CVR key, so an agent can route without opening a schema.

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?

Gives concrete when-to-use rules: use search_companies first when you only have a name, and use get_company instead when the user wants more than name/status history. It also warns which field answers the 'is it closed' question ('ophoert', not 'status' alone), which is guidance an agent cannot infer elsewhere.

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