lookup_by_ico
Get a single Czech company record by its IČO (8-digit Business ID). Returns official name, registered address, legal form, VAT ID (DIČ), founding date, and trade license activities. Returns null if IČO is not found in ARES.
This record as markdown: /tools/dev-cz-agents-ares/lookup-by-ico.md
What lookup_by_ico does on Ares
AI agents call lookup_by_ico 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 |
|---|---|---|---|
ico | string | Yes | Czech IČO — 7 or 8 digits. Examples: "11122234", "87654326". Auto-validated with MOD11 checksum. |
Parameters from the server's own tool schema.
Why lookup_by_ico is rated Low
This tool performs a straightforward lookup query against a public business register database. It retrieves publicly available company information by a known identifier (IČO) and does not modify, delete, execute code, or trigger external operations.
From the tool's definition Tool description explicitly states 'Get a single Czech company record' and 'Returns official name, registered address, legal form, VAT ID, founding date, and trade license activities.' The verb 'Get' and the return-only nature with 'Returns null if IČO is not…
Attacks that exploit this kind of access
The rule that runs lookup_by_ico 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 lookup_by_ico, this is the rule to start with:
lookup_by_ico 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 lookup_by_ico call is checked against it from then on.
Questions about lookup_by_ico
Get a single Czech company record by its IČO (8-digit Business ID). Returns official name, registered address, legal form, VAT ID (DIČ), founding date, and trade license activities. Returns null if IČO is not found in ARES. It is categorised as a Read tool in the Ares MCP Server, which means it retrieves data without modifying state.
lookup_by_ico accepts 1 parameter: ico. Required: ico. 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 lookup_by_ico: 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.
lookup_by_ico 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 lookup_by_ico 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 lookup_by_ico. 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.
lookup_by_ico 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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