send_stx · Stacks AI MCP Server MCP: Risk & Policy

WHAT IT DOES

What send_stx does on Stacks AI MCP Server

AI agents use send_stx to commit financial operations through Stacks AI MCP Server — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why send_stx needs a policy

This tool moves STX cryptocurrency tokens from one address to another, constituting a direct financial transfer on the blockchain. Such transfers are irreversible once confirmed on-chain. Misuse by an AI agent could result in loss of funds with no recourse, making this critical severity under the Financial category.

From the tool's definition 'Send STX tokens to another address' — directly transfers cryptocurrency assets to an external address

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_stx Approval-gated

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

View as policy code

policy.json

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

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Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Stacks AI MCP Server, so you can run agents against it safely.

FAQ

Questions about send_stx

What does the send_stx tool do? +

Send STX tokens to another address. It is categorised as a Financial tool in the Stacks AI MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on send_stx? +

Register the Stacks AI MCP Server MCP server in PolicyLayer and add a rule for send_stx: 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 Stacks AI MCP Server. Nothing to install.

What risk level is send_stx? +

send_stx 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 send_stx? +

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

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

send_stx is provided by the Stacks AI MCP Server MCP server (stack-ai-mcp/stacks-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.