withdrawFromYearnVault · Katana MCP Server MCP

WHAT IT DOES

What withdrawFromYearnVault does on Katana MCP Server

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

WHY IT NEEDS A POLICY

Why withdrawFromYearnVault needs a policy

This tool directly moves cryptocurrency assets (tokens) from a user's Yearn vault position, constituting a financial operation. While the action is reversible (users could redeposit), it commits a financial transaction and transfers control of assets.

From the tool's definition Tool enables withdrawal of tokens from a Yearn vault, which involves moving digital assets (tokens) out of a DeFi protocol.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

withdrawFromYearnVault Approval-gated

Any call to withdrawFromYearnVault 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": {
    "withdrawFromYearnVault": {
      "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 Katana MCP Server, so you can run agents against it safely.

FAQ

Questions about withdrawFromYearnVault

What does the withdrawFromYearnVault tool do? +

Withdraw tokens from a Yearn vault on Katana chain. It is categorised as a Financial tool in the Katana MCP Server MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on withdrawFromYearnVault? +

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

What risk level is withdrawFromYearnVault? +

withdrawFromYearnVault 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 withdrawFromYearnVault? +

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

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

withdrawFromYearnVault is provided by the Katana MCP Server MCP server (playainetwork/katana_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.