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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's job is to add context, which it does: public data only, public-sector customers/suppliers drawn specifically from SK/CZ contract registers, financials ordered newest first, and explicit exclusion of people/contact data. It does not say what happens on an unknown slug/domain or which key wins if both are supplied.

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?

A single sentence front-loads purpose and keying strategy before the field enumeration, so an agent can stop reading early if it only needs the trigger condition. The field list is dense but each item conveys what data is retrievable, though the colon-chained construction is heavy for one sentence.

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 correctly carries the burden of describing returns, and it does so thoroughly, including sources and register provenance. The remaining gaps are edge-case behavior (not-found handling, dual-key precedence, whether results are cached or rate limited), which are minor for a read-only single-record lookup.

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 both parameters are already fully documented with examples, making the baseline 3 appropriate. The description adds only the provenance hint that the slug can be obtained from search_signals, and leaves the precedence between slug and domain when both are passed unexplained.

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 and resource ('Public Evolc profile of one company') and scopes it to a single-entity lookup keyed by slug or domain, which cleanly separates it from the sibling search_* tools that return result sets. The enumerated field list makes the returned content unambiguous.

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 tells the agent where the slug comes from ('from search_signals') and that a website domain is an acceptable alternative key, which is a concrete usage path. It also bounds the use case with 'No people or contact details', though it never states when not to use it or what to do when neither key is available.

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