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

Annotations already declare readOnly, idempotent and non-destructive, and the description adds real value on top: a ≤12 KB size bound, deterministic output, the provenance guarantee ('missing data is marked, never invented'), and the licencing constraint on natural-person data. It omits latency/rate-limit behaviour, but the safety and data-quality profile is unusually well disclosed.

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?

Three information-dense sentences with the payload contents front-loaded and the identifier/country caveats after. Nearly every clause earns its place, though the long first enumeration is dense enough to slow scanning slightly.

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?

An output schema exists so return formatting need not be explained, yet the description still summarises the brief's sections, covers all three parameters, and states the data-quality guarantee. Nothing an agent needs to call this 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%, so baseline is 3, but the description adds a piece of operative logic the schema does not: the default is the 8-digit IČO shape and `country` is required for everything else, reinforcing the cross-country tie-break risk. The 'Never guess it — ask the user' instruction for `purpose` is genuinely actionable guidance beyond the schema text.

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 ('Compact, deterministic Markdown brief of one company') and enumerates exactly what it contains (identity, address, financials, credit score, NIS2, risk flags, key people). It also positions itself against siblings with 'The best single call for tell me about company X', so an agent can choose it over get_company_details, get_financials or check_compliance 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 context: use it as the single-call overview of one company, pass `country` for anything that is not an 8-digit IČO, and only supply `purpose` when the key holds full FO access. It stops short of naming explicit exclusions or pointing at specific alternatives for narrower needs (e.g. raw financials, network mapping), so it is clear but not fully routing.

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