claim_rewards · Justlend MCP: Risk & Policy

WHAT IT DOES

What claim_rewards does on Justlend

AI agents use claim_rewards 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 claim_rewards needs a policy

Claiming rewards triggers a financial transaction on the TRON blockchain that transfers tokens (JustLend mining rewards) to the configured wallet. This constitutes moving financial assets, placing it in the Financial category. Misuse could result in unauthorized token transfers or front-running of reward claims, hence high severity.

From the tool's definition Claim accrued JustLend mining rewards for the configured wallet

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

claim_rewards Approval-gated

Any call to claim_rewards 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": {
    "claim_rewards": {
      "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 claim_rewards

What does the claim_rewards tool do? +

Claim accrued JustLend mining rewards for the configured wallet. 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 claim_rewards? +

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

claim_rewards 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 claim_rewards? +

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

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

claim_rewards 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.