expand_cab · Windows Operations MCP: Risk & Policy

WHAT IT DOES

What expand_cab does on Windows Operations MCP

AI agents invoke expand_cab to trigger actions in Windows Operations MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why expand_cab needs a policy

CAB files are Windows cabinet archives. Expanding them involves file extraction and writing files to disk, which could be used to deploy arbitrary files. The empty description lowers confidence.

From the tool's definition Tool name 'expand_cab' suggests expanding/extracting CAB (Cabinet) archive files, which is an Execute-level operation; description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

expand_cab Rate-limited

expand_cab stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "expand_cab": {
      "limits": [
        {
          "counter": "expand_cab_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Windows Operations MCP, so you can run agents against it safely.

FAQ

Questions about expand_cab

What does the expand_cab tool do? +

expand_cab. It is categorised as a Execute tool in the Windows Operations MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on expand_cab? +

Register the Windows Operations MCP server in PolicyLayer and add a rule for expand_cab: 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 Windows Operations MCP. Nothing to install.

What risk level is expand_cab? +

expand_cab is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit expand_cab? +

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

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

expand_cab is provided by the Windows Operations MCP server (sandraschi/windows-operations-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.