prepareERC20Approval

Prepare an ERC20 token approval transaction for signing. Returns transaction data that can be signed and broadcast.

SERVERMCP Ethers Wallet SOURCEcrazyrabbitltc/mcp-ethers-server

Critical RISK CLASS

Category Financial

Parameters 00 required

Recommended Approval-gatedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/crazyrabbitltc-mcp-ethers-server/prepareerc20approval.md

WHAT IT DOES

What prepareERC20Approval does on MCP Ethers Wallet

AI agents use prepareERC20Approval to commit financial operations through MCP Ethers Wallet, usually the final step of a payment, billing, or trading workflow. A call moves real money.

RISK

Why prepareERC20Approval is rated Critical

ERC20 approvals grant a spender unlimited (or specified) access to a user's tokens. While this tool only 'prepares' the transaction data rather than executing it, the output is ready to be signed and broadcast, making it a direct precursor to a financial operation that could result in token loss if misused. Token approvals are a well-known attack vector in DeFi.

From the tool's definition Prepare an ERC20 token approval transaction for signing. Returns transaction data that can be signed and broadcast.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs prepareERC20Approval safely

PolicyLayer is an MCP gateway: it sits between your AI agents and MCP Ethers Wallet, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For prepareERC20Approval, this is the rule to start with:

prepareERC20Approval Approval-gated

Any call to prepareERC20Approval 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": {
    "prepareERC20Approval": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

GATE THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect MCP Ethers Wallet, apply this rule, and every prepareERC20Approval call is checked against it from then on.

FAQ

Questions about prepareERC20Approval

What does the prepareERC20Approval tool do? +

Prepare an ERC20 token approval transaction for signing. Returns transaction data that can be signed and broadcast. It is categorised as a Financial tool in the MCP Ethers Wallet MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on prepareERC20Approval? +

Register the MCP Ethers Wallet MCP server in PolicyLayer and add a rule for prepareERC20Approval: 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 Ethers Wallet. Nothing to install.

What risk level is prepareERC20Approval? +

prepareERC20Approval 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 prepareERC20Approval? +

Yes. Add a rate_limit block to the prepareERC20Approval 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 prepareERC20Approval completely? +

Set action: deny in the PolicyLayer policy for prepareERC20Approval. 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 prepareERC20Approval? +

prepareERC20Approval is provided by the MCP Ethers Wallet MCP server (crazyrabbitltc/mcp-ethers-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on MCP Ethers Wallet, and thousands of servers like it.

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