Check if a single domain is available for registration. Designed for parallel execution - launch multiple haiku agents to check many domains at once.
AI agents call check_domain to retrieve information from Domain MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool performs a read-only lookup against domain registrar availability data. It retrieves information (domain availability status) with no side effects, no modifications to data, and no commitments. While the server enables domain registration and other write/destructive actions, this specific tool is limited to checking/querying. The mention of 'parallel execution' reinforces its lightweight, query-only nature.
From the tool's definition Tool description states it 'Check[s] if a single domain is available for registration' - a pure query operation that retrieves availability status without modifying any data, creating side effects, or committing obligations.
Documented attack patterns abuse exactly the kind of access check_domain gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Domain MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for check_domain:
{
"version": "1",
"default": "deny",
"tools": {
"check_domain": {}
}
}check_domain is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Check if a single domain is available for registration. Designed for parallel execution - launch multiple haiku agents to check many domains at once. It is categorised as a Read tool in the Domain MCP MCP Server, which means it retrieves data without modifying state.
Register the Domain MCP server in PolicyLayer and add a rule for check_domain: 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 Domain MCP. Nothing to install.
check_domain 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 check_domain 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 check_domain. 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.
check_domain is provided by the Domain MCP server (joachimbrindeau/domain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Domain MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
3 Domain MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.