disconnect

THE RISK

Low Risk

Why disconnect needs a policy

Disconnecting a terminal session terminates the connection but does not delete, modify, or irreversibly destroy data. It is a session management operation. The worst case is disruption of an ongoing task, but no data is written or destroyed. It doesn't cleanly fit Read/Write/Execute/Destructive/Financial, so Other is most appropriate.

From the tool's definition Disconnect the active TN5250 session.

Documented attack patterns abuse exactly the kind of access disconnect gives an agent:

POLICY

How to control disconnect

PolicyLayer is an MCP gateway — it sits between your AI agents and Ibmi, and nothing reaches the server without passing your rules. This is the rule we recommend for disconnect:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "disconnect": {
      "limits": [
        {
          "counter": "disconnect_rate",
          "window": "minute",
          "max": 60,
          "scope": "grant"
        }
      ]
    }
  }
}

disconnect gets a rate cap, and everything else on the server is denied unless you say otherwise.

Create a free account and register Ibmi — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

SET A RULE FOR THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Ibmi tools

Execute connect Connect to an IBM i system via TN5250. Execute send_key Send an attention/function key and wait for the host response. Execute send_keys Type text into the current input field at the cursor position. Execute set_cursor Position the cursor at the specified location. Write upload_file Upload a file from the local system to the IBM i. Read download_file Download a file from the IBM i to the local system. Read read_screen read_screen

All 8 Ibmi tools →

Other tools on other servers

Android Forensics ADB MCP Server generate_app_analysis_report Ethereum Tools add Math MCP Server complex_analysis_suite Crypto_MCP aes_encrypt

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Tool risk categories → How PolicyLayer classifies MCP tools by what they can do.
MCP tool → What an MCP tool is and how clients discover and call it.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about disconnect

What does the disconnect tool do? +

Disconnect the active TN5250 session. It is categorised as a Other tool in the Ibmi MCP Server, which means it performs auxiliary operations.

How do I enforce a policy on disconnect? +

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

What risk level is disconnect? +

disconnect is a Other tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit disconnect? +

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

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

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

Enforce policy on every Ibmi tool call.

Start from Ibmi, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →