approve_liquidator_token · Justlend MCP: Risk & Policy

WHAT IT DOES

What approve_liquidator_token does on Justlend

AI agents use approve_liquidator_token to create or update resources in Justlend — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Justlend environment.

WHY IT NEEDS A POLICY

Why approve_liquidator_token needs a policy

This tool approves token spending, which is a Write operation—it modifies the state of token allowances reversibly. While approval itself is not destructive, the high severity reflects that misconfiguration could enable unauthorized liquidation or fund transfers. The tool is contextual to financial activities (lending/liquidation) but the direct action is token authorization, not fund movement itself.

From the tool's definition Tool name 'approve_liquidator_token' and description 'Approve loan token spending for the Moolah public liquidator contract' indicate this creates or modifies token spending allowances on behalf of the user, a reversible authorization.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

approve_liquidator_token Rate-limited

approve_liquidator_token stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "approve_liquidator_token": {
      "limits": [
        {
          "counter": "approve_liquidator_token_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about approve_liquidator_token

What does the approve_liquidator_token tool do? +

Approve loan token spending for the Moolah public liquidator contract. It is categorised as a Write tool in the Justlend MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on approve_liquidator_token? +

Register the Justlend MCP server in PolicyLayer and add a rule for approve_liquidator_token: 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 Justlend. Nothing to install.

What risk level is approve_liquidator_token? +

approve_liquidator_token is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit approve_liquidator_token? +

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

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

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