open_url · MCP Connect MCP: Risk & Policy

WHAT IT DOES

What open_url does on MCP Connect

AI agents invoke open_url to trigger actions in MCP Connect. 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 open_url needs a policy

Opening a URL triggers an external operation—either launching a web page in a browser or invoking an app via a deep link. This is not a passive read; it causes the simulator to perform an action (navigate, launch app, etc.) whose effects depend on the URL argument. Deep links in particular can trigger sensitive in-app actions, making this Execute with medium severity.

From the tool's definition Opens a URL in the simulator (supports app deep links and web URLs)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open_url Rate-limited

open_url 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": {
    "open_url": {
      "limits": [
        {
          "counter": "open_url_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 MCP Connect, so you can run agents against it safely.

FAQ

Questions about open_url

What does the open_url tool do? +

Opens a URL in the simulator (supports app deep links and web URLs). It is categorised as a Execute tool in the MCP Connect MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on open_url? +

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

What risk level is open_url? +

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

Can I rate-limit open_url? +

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

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

open_url is provided by the MCP Connect MCP server (plaintest/mcp-connect). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.