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

The annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true and idempotentHint=false; the description adds genuine context beyond them: the data is weekly open data (freshness), each call costs $0.01 via x402 USDC or a card key, first 25 free, failed calls free, and the explicit warning that repeats are not free — which explains the non-idempotent, billed nature of the call. It does not state rate limits or what a failed/empty lookup returns, so it falls just short of full disclosure.

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-loads identifiers and returned fields before the use case, pricing, and safety caveat, and every clause carries information. It is dense — a single long block mixing scope, fields, pricing, and annotations — but no sentence is pure 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 carries the return-value burden itself and does so by listing the substantive fields (names, legal form, registration date, status, bankruptcy/liquidation, VAT/F-tax/employer activity, SNI, address). Combined with freshness (weekly), cost model, and a safety statement, an agent has everything needed to decide and call correctly.

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%, so all five parameters (city, name, limit, orgnr, checkVat) are already documented in the input schema. The description only adds an example value (orgnr=556703-7485) and repeats the two identifier formats the schema already specifies, so the marginal value beyond structured data is small. Baseline 3 is appropriate.

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 specific verb+resource: retrieves a Swedish company from Bolagsverket/SCB by organisationsnummer or name, and enumerates the returned facts (legal form, status, bankruptcy, SNI, address). The 'Swedish' jurisdiction qualifier plus the register names distinguish it from the other national company tools in the sibling list (fi_company, no_company, company_lookup) without ambiguity.

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 a concrete when-to-use ('verify a Swedish customer or supplier before invoicing') and an explicit scope exclusion ('Register facts only, not a credit report'), which prevents the agent from over-reading the result as a creditworthiness signal. It stops short of naming an alternative tool for credit checks or for non-Swedish entities, so the routing guidance is clear but not fully closed.

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