close_position

THE RISK

Critical Risk

Why close_position needs a policy

Closing a position involves selling (or buying to cover) an asset on a live trading platform, directly impacting the user's financial portfolio. This is an irreversible financial action that moves money and realizes gains or losses. It ranks at the highest severity because misuse by an AI agent could cause significant, unrecoverable financial harm.

From the tool's definition 'Close an open position for a specific symbol' — closing a trading position liquidates financial holdings, committing a real financial transaction that cannot be undone once executed.

Documented attack patterns abuse exactly the kind of access close_position gives an agent:

POLICY

How to control close_position

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 close_position:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "close_position": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

Any call to close_position is blocked until a human approves it. The rest of the server keeps working.

Create a free account and register Alpaca Trading MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

GATE THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Alpaca Trading MCP Server tools

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All 8 Alpaca Trading MCP Server tools →

Financial tools on other servers

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Go deeper

Critical-risk tools in Alpaca Trading MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Human-in-the-loop → When a tool call should wait for a person — and when policy can decide alone.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
How to Add Spending Controls to Any MCP Agent →
Rate Limiting MCP Tool Calls: A Practical Guide →

FAQ

Questions about close_position

What does the close_position tool do? +

Close an open position for a specific symbol. 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.

How do I enforce a policy on close_position? +

Register the Alpaca Trading MCP Server MCP server in PolicyLayer and add a rule for close_position: 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.

What risk level is close_position? +

close_position is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit close_position? +

Yes. Add a rate_limit block to the close_position 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.

How do I block close_position completely? +

Set action: deny in the PolicyLayer policy for close_position. 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.

What MCP server provides close_position? +

close_position 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.

Enforce policy on every Alpaca Trading MCP Server tool call.

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.

CHECK YOUR STACK →