freeze_account

THE RISK

Critical Risk

Why freeze_account needs a policy

Freezing a trading account is a severe financial action that prevents any trades from being executed and potentially locks access to funds. This directly impacts financial operations and cannot be easily reversed without explicit unfreeze action. The blast radius is critical as it could halt all trading activity for an account.

From the tool's definition 'Freeze a trading account' - freezing a trading account halts all trading activity and access to funds

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

POLICY

How to control freeze_account

PolicyLayer is an MCP gateway — it sits between your AI agents and Paper MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for freeze_account:

policy.json

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

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

Create a free account and register Paper 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.

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EXPLORE

Related tools and policies

More Paper MCP Server tools

Financial upgrade_to_margin Upgrade portfolio to margin account Financial create_batch_orders Create multiple orders at once Financial create_order Create a new trading order Destructive cancel_all_account_orders Cancel all orders for an account Destructive cancel_order Cancel an existing order Destructive reset_portfolio Reset portfolio to initial state Write create_portfolio Create a new portfolio Write update_account Update account details

All 23 Paper MCP Server tools →

Financial tools on other servers

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Go deeper

Critical-risk tools in Paper 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 freeze_account

What does the freeze_account tool do? +

Freeze a trading account. It is categorised as a Financial tool in the Paper MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on freeze_account? +

Register the Paper MCP Server MCP server in PolicyLayer and add a rule for freeze_account: 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 Paper MCP Server. Nothing to install.

What risk level is freeze_account? +

freeze_account 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 freeze_account? +

Yes. Add a rate_limit block to the freeze_account 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 freeze_account completely? +

Set action: deny in the PolicyLayer policy for freeze_account. 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 freeze_account? +

freeze_account is provided by the Paper MCP Server MCP server (paperinvest/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Paper MCP Server tool call.

Start from Paper MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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