validate_dic
Validate a Czech DIČ (VAT ID). Format check: "CZ" + 8-10 digits. For 8-digit tail (legal entities) also runs MOD11 checksum against the embedded IČO.
This record as markdown: /tools/dev-cz-agents-ares/validate-dic.md
What validate_dic does on Ares
AI agents call validate_dic to retrieve information from Ares without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
dic | string | Yes | Czech DIČ — e.g., "CZ26168685". Whitespace and case tolerated. |
Parameters from the server's own tool schema.
Why validate_dic is rated Low
The validate_dic tool performs input validation only (format checking and checksum verification). It does not retrieve, create, modify, or delete data; it does not execute code or trigger external operations; and it does not involve financial transactions. This is a deterministic validation function that returns pass/fail results, making it a Read operation with minimal security risk.
From the tool's definition Tool description states it 'Validate a Czech DIČ (VAT ID)' with 'Format check' and 'MOD11 checksum' validation—purely a data validation/verification operation with no side effects, data retrieval, or modifications.
Attacks that exploit this kind of access
The rule that runs validate_dic safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Ares, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For validate_dic, this is the rule to start with:
validate_dic is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Ares, apply this rule, and every validate_dic call is checked against it from then on.
Questions about validate_dic
Validate a Czech DIČ (VAT ID). Format check: "CZ" + 8-10 digits. For 8-digit tail (legal entities) also runs MOD11 checksum against the embedded IČO. It is categorised as a Read tool in the Ares MCP Server, which means it retrieves data without modifying state.
validate_dic accepts 1 parameter: dic. Required: dic. The full parameter table on this page comes from the server's own tool schema.
Register the Ares MCP server in PolicyLayer and add a rule for validate_dic: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Ares. Nothing to install.
validate_dic is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the validate_dic rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for validate_dic. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
validate_dic is provided by the Ares MCP server (https://ares.cz-agents.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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