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

No annotations are provided, so the description carries the burden. It discloses that this is a basic ARES register lookup and enumerates the returned fields, giving a clear sense of scope. It does not mention behavior for invalid IDs, missing records, or whether the VAT DIČ is verified, which are useful but secondary details.

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?

The description is two short sentences with no filler. The purpose and input format are front-loaded, and every phrase adds information.

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 read-only lookup, the description covers what the tool does, what it returns, and how to format the input. It does not explain not-found behavior, but that is minor given the tool's simplicity and lack of an output schema.

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?

The schema already documents the single parameter with examples, and the description adds useful format constraints (8 digits for IČO, CZ+10 for DIČ). This goes beyond the schema's basic description and helps agents construct valid inputs.

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 clearly states the tool does a lookup of Czech companies by IČO or DIČ, and it lists the specific data returned. The exact-ID framing distinguishes it from broader search tools, though it does not explicitly name sibling tools for contrast.

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 input requirement 'IČO (8 digits) or DIČ (CZ+10)' strongly implies this tool is for exact identifier lookup. However, it does not explicitly say when to prefer search_company, check_vat, or entity_status, leaving some ambiguity about alternatives.

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