repay · Justlend MCP: Risk & Policy

WHAT IT DOES

What repay does on Justlend

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

WHY IT NEEDS A POLICY

Why repay needs a policy

This tool moves crypto assets on a DeFi lending protocol (JustLend DAO on TRON) to repay debt obligations. It commits financial transactions on-chain, transferring tokens back to the lending market. This directly involves financial operations — repaying borrowed funds — which falls under the Financial category. Misuse could result in unintended asset transfers or manipulation of a user's lending position.

From the tool's definition Repay borrowed assets to a JustLend market

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

repay Approval-gated

Any call to repay 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": {
    "repay": {
      "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 Justlend, so you can run agents against it safely.

FAQ

Questions about repay

What does the repay tool do? +

Repay borrowed assets to a JustLend market. It is categorised as a Financial tool in the Justlend MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on repay? +

Register the Justlend MCP server in PolicyLayer and add a rule for repay: 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 repay? +

repay 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 repay? +

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

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

repay 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.