Start the purchase flow for a domain via Stripe's Machine Payments Protocol (MPP). MPP lets autonomous agents pay with fiat (cards, Link) or stablecoins via Shared Payment Tokens, with no browser checkout. Two-step flow: Step 1: Call this tool to get an order_id and pay_url. Step 2: Make an HTTP ...
Risk signalsHigh parameter count (11 properties)
Part of the Instadomain server.
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AI agents invoke buy_domain_mpp 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_mpp 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_mpp": {
"limits": [
{
"counter": "buy_domain_mpp_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_mpp 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 a domain via Stripe's Machine Payments Protocol (MPP). MPP lets autonomous agents pay with fiat (cards, Link) or stablecoins via Shared Payment Tokens, with no browser checkout. Two-step flow: Step 1: Call this tool to get an order_id and pay_url. Step 2: Make an HTTP GET request to the pay_url with an MPP-enabled HTTP client. The server responds with HTTP 402 + WWW-Authenticate; the client creates a Shared Payment Token and retries with an Authorization header. The server charges the SPT through Stripe and kicks off domain registration. After payment, call get_domain_status(order_id) to poll until complete. Requires: An MPP-compatible client configured to mint SPTs against the server's advertised Stripe Business Network profile. 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. phone: Phone number in format +1.5551234567. org_name: Organization name (optional). Returns: Dict with order_id, pay_url (full URL), price_cents, price_display, network_id, and payment_method_types.. 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_mpp: 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_mpp 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_mpp 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_mpp. 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_mpp 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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