computer_open_app · LocalAnt MCP: Risk & Policy

WHAT IT DOES

What computer_open_app does on LocalAnt

AI agents invoke computer_open_app to trigger actions in LocalAnt. 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 computer_open_app needs a policy

Opening an application is an execution action: it runs a program on the host machine. While it doesn't directly delete data or move money, launching arbitrary applications can have wide-ranging side effects depending on which app is opened. Severity is medium because the action is bounded to opening/foregrounding apps rather than arbitrary shell execution, but misuse (e.g., opening a malicious app) could cause harm.

From the tool's definition 'Open (or bring to front) an application by name' — launches or foregrounds a local application on the PC

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

computer_open_app Rate-limited

computer_open_app 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": {
    "computer_open_app": {
      "limits": [
        {
          "counter": "computer_open_app_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 LocalAnt, so you can run agents against it safely.

FAQ

Questions about computer_open_app

What does the computer_open_app tool do? +

Open (or bring to front) an application by name, e.g. It is categorised as a Execute tool in the LocalAnt MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on computer_open_app? +

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

What risk level is computer_open_app? +

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

Can I rate-limit computer_open_app? +

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

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

computer_open_app is provided by the LocalAnt MCP server (yuga-hashimoto/localant). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.