Start the purchase flow for an available domain via Stripe checkout. IMPORTANT: Before calling this tool, you MUST first call check_domain to get the price, then clearly show the user the price and get their explicit confirmation before proceeding. Never call buy_domain without the user seeing an...
Risk signalsHigh parameter count (11 properties)
Part of the Instadomain server.
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AI agents invoke buy_domain to trigger processes or run actions in Instadomain. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
buy_domain can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"buy_domain": {
"limits": [
{
"counter": "buy_domain_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full Instadomain policy for all 12 tools.
These attack patterns abuse exactly the kind of access buy_domain gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Start the purchase flow for an available domain via Stripe checkout. IMPORTANT: Before calling this tool, you MUST first call check_domain to get the price, then clearly show the user the price and get their explicit confirmation before proceeding. Never call buy_domain without the user seeing and approving the price first. The registrant contact details are required because the domain will be registered in the buyer's name (they become the legal owner). WHOIS privacy is enabled by default, so these details are not publicly visible. Creates a Stripe checkout session. IMPORTANT: After this tool returns, you MUST open the checkout_url by running the shell command open "<checkout_url>" (macOS/Linux) so the payment page launches automatically in the user's default browser. Do NOT paste the URL as a link. Tell the user the page has been opened and they can complete payment there. Args: domain: The domain to purchase (e.g. "coolstartup.com"). first_name: Registrant's first name. last_name: Registrant's last name. email: Registrant's email address. address1: Registrant's street address. city: Registrant's city. state: Registrant's state or province. postal_code: Registrant's postal/zip code. country: 2-letter ISO country code (e.g. "US", "GB", "DE"). phone: Phone number in format +1.5551234567. org_name: Organization name (optional, leave empty for individuals). Returns: Dict with order_id, checkout_url, price_cents, and price_display.. It is categorised as a Execute tool in the Instadomain MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Instadomain MCP server in PolicyLayer and add a rule for buy_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 Instadomain. Nothing to install.
buy_domain is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the buy_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 buy_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.
buy_domain is provided by the Instadomain MCP server (https://instadomain.fly.dev/mcp/). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 12 Instadomain tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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