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

Annotations already cover readOnly/idempotent/non-destructive/openWorld, and the description still adds real context: it consumes a monthly quota, requires an authenticated geoa account, and is strictly company-level with no person data. The only gap is what happens on a failed match or partial registry hit.

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?

Two dense sentences that front-load the action and the data source, then append the quota/auth/scope constraints. Every clause earns its place; only the 'etc.' after the registry list is slightly loose.

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 usefully enumerates the returned fields (name, company number, industry code, legal form, status) and discloses the quota, auth and company-only constraints. It stops short of describing behavior when no registry match is found, which is the remaining gap for a lookup tool.

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%, with every parameter documented including the country default (dk) and that company_name improves matching, so the schema carries the load. The description adds nothing about parameter format or behavior beyond what is already there — baseline 3.

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?

A specific verb ('Enrich') plus resource ('a company domain') plus the source of the data (Nordic Data: CVR/Brønnøysund/Bolagsverket) and the exact fields returned. That clearly separates it from siblings like geoa_radar_find_prospects (discovery) and geoa_radar_score_prospects (scoring) without opening either 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?

It states what you must supply (a domain) and the cost of using it ('counts against the plan's monthly lookup quota') plus the auth prerequisite, which is genuinely decision-relevant. But it never names an alternative tool or a when-not condition, so the agent has to infer that this is the lookup step after prospect discovery rather than being told.

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