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

Annotations already declare readOnlyHint, openWorldHint and destructiveHint=false, so safety is covered; the description still adds real operational context: fresh-nightly sync, 24-month window, active-only filtering, 1 credit per page on every plan, and that 'total' avoids paging. Return field caveats (kommunekode can be null, postnummer is the reliable location field) are genuine behavioral disclosures beyond annotations.

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?

Front-loaded with the definition and the 24-month window before any field notes, and nearly every clause carries decision-relevant information. It is dense and slightly crowded in the middle (industry/legal-form/location notes packed into one run), but no sentence is filler.

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 still tells the agent what a row contains, how results are ordered, that 'total' is the full match count, minimum cost implications, and where to go for fields not present. For a 9-parameter, open-ended list tool this leaves nothing an agent needs unknown before calling.

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%, so the baseline is met by the schema alone; the description nonetheless adds non-obvious meaning, notably that 'virksomhedsform' is the full legal-form name while 'virksomhedstype' is CVR's short code, and that location should key off postnummer rather than kommunekode. It does not restate syntax or format constraints already in the schema, which is 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?

Names a specific resource and scope: 'active companies founded within the last 24 months, newest founding date first', plus the fields returned and the nightly CVR sync. Explicitly distinguishes itself from search_companies ('to find one particular company by name or CVR number') 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?

States when to use it (browsing new registrations, 'which companies were founded', counting via 'total') and when not to, naming three alternatives: search_companies for a specific company, get_contact_details and get_financials for address/contact/accounts. Exclusion of inactive companies is also stated.

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