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

Annotations already cover read-only, idempotent, open-world behavior, and the description goes beyond them by disclosing the data provenance and the paid-call model (0.005 USDC per successful call via x402 on Base, errors free). That pricing/auth detail is exactly the kind of context an agent cannot get from annotations or schema.

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 compact sentences: the resource plus returned fields first, then the cost model. No filler, no restatement of the tool name, and the most decision-relevant facts are front-loaded.

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 one-parameter lookup with no output schema, the description compensates by enumerating the returned fields and the cost of a call. It is essentially complete; only the missing sibling routing keeps it from a 5.

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 pattern, mod-11 check, and 9-digit format are all documented in the schema itself. The description adds nothing about the orgnr parameter, so the schema-driven baseline of 3 applies.

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 concrete verb+resource ('One Norwegian legal entity from Brønnøysundregistrene') and enumerates the returned facets (status, form, NACE industry, address, employees, VAT). This clearly distinguishes it from siblings like get_finnish_company and search_companies, which cover different registers or list-style queries.

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 single-entity framing plus the required 9-digit orgnr implies a point-lookup use case versus the search_* siblings, but the description never says when to use this over search_companies or get_company_awards/tenders. Usage is inferable but not stated.

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