AI agents call schwab_cancel_order to permanently remove resources in Open Stocks MCP — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Canceling an order is an irreversible action that terminates a pending financial transaction. Once canceled, the order state cannot be restored without manual intervention by the user. This is a destructive operation on financial data.
From the tool's definition Tool name 'schwab_cancel_order' and description 'Cancel a specific Schwab order' indicate irreversible cancellation of a financial order.
Documented attack patterns abuse exactly the kind of access schwab_cancel_order gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Open Stocks MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for schwab_cancel_order:
{
"version": "1",
"default": "deny",
"hide": [
"schwab_cancel_order"
]
}schwab_cancel_order disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
Free to start. No card required.
Cancel a specific Schwab order. It is categorised as a Destructive tool in the Open Stocks MCP MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Open Stocks MCP server in PolicyLayer and add a rule for schwab_cancel_order: 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 Open Stocks MCP. Nothing to install.
schwab_cancel_order is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the schwab_cancel_order 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 schwab_cancel_order. 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.
schwab_cancel_order is provided by the Open Stocks MCP server (open-agent-tools/open-stocks-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Open Stocks 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.
152 Open Stocks MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.