set_network · Justlend MCP: Risk & Policy

WHAT IT DOES

What set_network does on Justlend

AI agents use set_network 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 set_network needs a policy

This tool creates or modifies a global state setting (the default network) that persists and influences all downstream JustLend operations. While reversible (the network can be changed again), it is a Write operation because it alters stored configuration. It is not Execute because it does not run arbitrary code or trigger external operations—it merely sets a parameter.

From the tool's definition Tool description states it 'Set[s] the global default network used by all JustLend operations unless explicitly overridden.' This modifies a configuration setting that affects subsequent operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_network Rate-limited

set_network 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": {
    "set_network": {
      "limits": [
        {
          "counter": "set_network_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 set_network

What does the set_network tool do? +

Set the global default network used by all JustLend operations unless explicitly overridden. 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 set_network? +

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

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

Can I rate-limit set_network? +

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

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

set_network 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.