validate_polish_regonCheck if a Polish REGON business registry number (9 or 14 digits) is valid. Returns validity status, the number, and its length.
Validate a Polish REGON (business registry number — 9 or 14 digits).
Returns {'valid': bool, 'regon': str, 'length': int}.
| Name | Required | Description | Default |
|---|---|---|---|
| regon | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden. It discloses the return shape ('valid', 'regon', 'length'), signals a safe read-only validation operation, and specifies the accepted 9 or 14 digit format. It does not mention checksum behavior or error handling for malformed input, but for a simple validator this is a minor gap.
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?
Two short sentences with no filler. The action and target are front-loaded, and the return format is stated compactly. Every phrase earns its place.
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 simple single-parameter validation tool with an output schema, the description is nearly complete. It covers what is validated, the accepted length, and the return keys. Missing details like checksum validation or behavior on invalid formats are useful but not critical for invoking the tool 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 coverage is 0%, so the description must compensate for the bare string parameter. It does so by explaining REGON is a 9 or 14 digit business registry number, which gives the agent concrete format expectations beyond the schema. It does not discuss normalization or edge cases, but the single parameter is adequately clarified.
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 a specific verb ('Validate') and resource ('Polish REGON — 9 or 14 digits'), clearly distinguishing it from siblings like validate_polish_nip. The parenthetical format detail makes the tool's exact purpose immediately recognizable.
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 clearly implies when to use this tool: whenever a Polish REGON number needs validation. It does not explicitly name alternatives or exclusions, but the resource-specific wording provides sufficient context for an agent to select it over NIP or invoice validation tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.