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

Annotations already cover safety (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description adds two useful traits — data source ('public register', 'with provenance') and cost ('Free') — but says nothing about behavior when regNo is unknown or invalid, whether results can be stale, or what 'provenance' concretely contains.

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 front-loaded sentence that identifies the resource and its fields, then appends cost. No filler, nothing an agent has to scan past.

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 two-parameter read-only lookup with no output schema, the field enumeration effectively tells the agent what comes back, and the annotations cover the safety profile. Missing only error/not-found behavior to be fully complete.

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% and both parameters carry descriptions including the IČO/CUI mapping and the country enum, so the schema does the heavy lifting. The description adds nothing about the parameters themselves, which is acceptable at full coverage but earns only the baseline.

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?

The description names the resource concretely ('basic company card from the public register') and enumerates the fields it returns (name, legal form, status, seat, main activity, VAT flag), which lets an agent distinguish it from get_financials and get_risk. It never states the verb ('returns') explicitly and doesn't name siblings, so it stops short of a 5.

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?

Usage is only implied: 'basic' and 'Free' suggest this is the cheap first-look tool before deeper lookups like get_financials or get_risk, but no when-to-use/when-not or alternative is named. An agent can infer the role but must guess the routing rules.

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