Requires checkout:write scope. Change the quantity of a line item in an open cart, or remove it entirely. Set quantity to 0 to remove the item. Get the item_id from get_cart or the cart field in the add_to_cart response. Returns the updated cart state. The per-item quantity ceiling applies here t...
Part of the Kifly — Agentic Commerce & Payments server.
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AI agents use update_cart_item 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 update_cart_item 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": {
"update_cart_item": {
"limits": [
{
"counter": "update_cart_item_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 update_cart_item 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. Change the quantity of a line item in an open cart, or remove it entirely. Set quantity to 0 to remove the item. Get the item_id from get_cart or the cart field in the add_to_cart response. Returns the updated cart state. The per-item quantity ceiling applies here too — call get_platform_limits to check the current limit. Exceeding it returns 400 QUANTITY_EXCEEDS_LIMIT.. 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 update_cart_item: 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.
update_cart_item 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 update_cart_item 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 update_cart_item. 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.
update_cart_item 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.
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