Rejestr VAT

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

With no annotations, the description must fully convey behavioral traits. It only states basic actions (check status, validate checksum) but omits details such as whether the operation is read-only, if it makes any external calls, or any side effects. The term 'mock' suggests it's a simulation, but this is not explicitly explained.

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 extremely concise, consisting of a single sentence that efficiently communicates the tool's core functionality. No unnecessary words or verbose phrasing detract from its clarity.

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?

The tool has one parameter and no output schema. While the description covers the operation, it fails to specify the output format or return values, which are essential for a complete understanding. The agent is left guessing what the response contains, making the description incomplete.

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 provides no descriptions for the 'nip' parameter (0% coverage). The description adds minimal semantic value by mentioning NIP checksum control, implying the parameter is validated. However, it lacks format details, examples, or constraints that would fully compensate for the schema gap.

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's purpose: checking the VAT status of a contractor ('Status kontrahenta w rejestrze podatników VAT') and validating the NIP checksum ('kontrola sumy kontrolnej NIP'). This provides a specific verb and resource, and despite the lack of sibling tools, the purpose is 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?

No usage guidelines are provided. The description does not indicate when to use this tool versus alternatives, nor does it mention prerequisites or exclusions. This leaves the agent without context on appropriate usage scenarios.

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