session_set_variable · It2 MCP: Risk & Policy

WHAT IT DOES

What session_set_variable does on It2mcp

AI agents use session_set_variable to create or update resources in It2mcp — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your It2mcp environment.

WHY IT NEEDS A POLICY

Why session_set_variable needs a policy

This tool modifies session state by writing/updating a variable value in an iTerm2 session. It is reversible (variables can be changed again), so it falls under Write rather than Destructive. Misuse could alter session behavior or expose sensitive configuration, warranting medium severity.

From the tool's definition Set the value of an iTerm2 session variable

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

session_set_variable Rate-limited

session_set_variable 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": {
    "session_set_variable": {
      "limits": [
        {
          "counter": "session_set_variable_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 It2mcp, so you can run agents against it safely.

FAQ

Questions about session_set_variable

What does the session_set_variable tool do? +

Set the value of an iTerm2 session variable. It is categorised as a Write tool in the It2mcp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on session_set_variable? +

Register the It2 MCP server in PolicyLayer and add a rule for session_set_variable: 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 It2mcp. Nothing to install.

What risk level is session_set_variable? +

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

Can I rate-limit session_set_variable? +

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

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

session_set_variable is provided by the It2 MCP server (urjitbhatia/it2mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.