AI agents use place_stop_limit_order to commit financial operations through Alpaca Trading MCP Server — usually the final step of a payment, billing, or trading workflow. A call moves real money.
Despite the empty description, the tool name clearly indicates it places a stop-limit order on a financial trading platform. Sibling tools confirm this is part of a suite of order-placement tools. Placing orders commits real financial transactions and carries critical risk if misused by an AI agent.
From the tool's definition Tool name 'place_stop_limit_order' on a server described as interfacing with 'Alpaca trading API' to 'place trades'; sibling tools include 'place_limit_order', 'place_market_order', 'place_stop_order' — all order-placement tools.
Documented attack patterns abuse exactly the kind of access place_stop_limit_order gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Alpaca Trading MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for place_stop_limit_order:
{
"version": "1",
"default": "deny",
"tools": {
"place_stop_limit_order": {
"deny_if": [
{
"conditions": [],
"on_deny": "Requires human approval."
}
]
}
}
} Any call to place_stop_limit_order is blocked until a human approves it. The rest of the server keeps working.
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place_stop_limit_order. It is categorised as a Financial tool in the Alpaca Trading MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Alpaca Trading MCP Server MCP server in PolicyLayer and add a rule for place_stop_limit_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 Alpaca Trading MCP Server. Nothing to install.
place_stop_limit_order is a Financial 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 place_stop_limit_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 place_stop_limit_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.
place_stop_limit_order is provided by the Alpaca Trading MCP Server MCP server (laukikk/alpaca-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Alpaca Trading MCP Server, 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.
8 Alpaca Trading MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.