Requires checkout:write scope. Requires set_shipping_address to have been called first. Returns 400 invalid_shipping if no address is on the cart, or 400 delivery_unavailable if the buyer's address is outside the seller's coverage. Cart total must not exceed the platform cap (kifly://platform/lim...
Part of the Kifly — Agentic Commerce & Payments server.
Free to start. No card required.
AI agents use checkout to create or modify resources in Kifly — Agentic Commerce & Payments. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call checkout repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Kifly — Agentic Commerce & Payments.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"checkout": {
"limits": [
{
"counter": "checkout_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Kifly — Agentic Commerce & Payments policy for all 18 tools.
These attack patterns abuse exactly the kind of access checkout gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Requires checkout:write scope. Requires set_shipping_address to have been called first. Returns 400 invalid_shipping if no address is on the cart, or 400 delivery_unavailable if the buyer's address is outside the seller's coverage. Cart total must not exceed the platform cap (kifly://platform/limits). On success: returns payment_url (Stripe link), session_id for order_status, and amount breakdown. To pre-fill the buyer's email on the payment page, pass email — ask the buyer for it in plain language ('what email should the receipt go to?'). Never ask the buyer to paste a token. buyer_token_status in the response reports whether an (internal) token was applied: 'resolved' / 'invalid' / 'none' — an invalid token is NOT an error response. On 502/503 errors, check retryable: true in the body — those are transient upstream faults; wait retry_after_seconds then retry once.. It is categorised as a Write tool in the Kifly — Agentic Commerce & Payments MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Kifly — Agentic Commerce & Payments MCP server in PolicyLayer and add a rule for checkout: 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 Kifly — Agentic Commerce & Payments. Nothing to install.
checkout is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the checkout 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 checkout. 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.
checkout is provided by the Kifly — Agentic Commerce & Payments MCP server (https://kifly.ai/api/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 18 Kifly — Agentic Commerce & Payments tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.