vscode_open_webview

THE RISK

High Risk

Why vscode_open_webview needs a policy

Opening a webview panel triggers an external operation within VSCode — it activates a command or surfaces extension-provided custom UI, which may have side effects depending on the webview's functionality. This goes beyond a read (no data is just queried) and qualifies as Execute since it triggers an operation whose effects depend on the specific command/extension invoked.

From the tool's definition Open a webview panel by its title or command. Webviews are used by extensions for custom UI.

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

POLICY

How to control vscode_open_webview

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

policy.json

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

vscode_open_webview 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.

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

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More VSCode Automation MCP tools

Destructive vscode_clear_console Clear captured console logs. Execute vscode_execute_command Execute a VSCode command programmatically. Use this to trigger any command available in th Execute vscode_execute_script Execute arbitrary JavaScript code in the VSCode window context (like DevTools console). Ha Execute vscode_go_to_definition Trigger Go to Definition (F12) on the current cursor position. Execute vscode_hover Hover over an element for a specified duration to trigger hover effects. Execute vscode_initialize Initialize the VSCode automation driver. This is called automatically on first tool use, b Execute vscode_trigger_completion Trigger IntelliSense/code completion (Ctrl+Space) and optionally wait for items. Execute vscode_trigger_hover Trigger hover on an element and optionally wait for tooltip to appear. Returns tooltip con

All 61 VSCode Automation MCP tools →

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Go deeper

High-risk tools in VSCode Automation MCP → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about vscode_open_webview

What does the vscode_open_webview tool do? +

Open a webview panel by its title or command. Webviews are used by extensions for custom UI. It is categorised as a Execute tool in the VSCode Automation 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 vscode_open_webview? +

Register the VSCode Automation MCP server in PolicyLayer and add a rule for vscode_open_webview: 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 VSCode Automation MCP. Nothing to install.

What risk level is vscode_open_webview? +

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

Can I rate-limit vscode_open_webview? +

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

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

vscode_open_webview is provided by the VSCode Automation MCP server (sukarth/vscode-automation-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every VSCode Automation MCP tool call.

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

CHECK YOUR STACK →