send-transaction · MCP EVM Signer MCP: Risk & Policy

WHAT IT DOES

What send-transaction does on MCP EVM Signer

AI agents use send-transaction to commit financial operations through MCP EVM Signer — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why send-transaction needs a policy

Sending ETH is an irreversible financial transaction that moves real monetary value. Misuse by an AI agent could result in permanent loss of funds. This clearly falls under the Financial category, which is the most severe applicable category.

From the tool's definition "Send ETH to an address" — directly transfers Ethereum (a financial asset) from a managed wallet to another address.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send-transaction Approval-gated

Any call to send-transaction 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-transaction": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

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

FAQ

Questions about send-transaction

What does the send-transaction tool do? +

Send ETH to an address. It is categorised as a Financial tool in the MCP EVM Signer MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on send-transaction? +

Register the MCP EVM Signer MCP server in PolicyLayer and add a rule for send-transaction: 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 MCP EVM Signer. Nothing to install.

What risk level is send-transaction? +

send-transaction 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-transaction? +

Yes. Add a rate_limit block to the send-transaction 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-transaction completely? +

Set action: deny in the PolicyLayer policy for send-transaction. 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-transaction? +

send-transaction is provided by the MCP EVM Signer MCP server (zhangzhongnan928/mcp-evm-signer). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.