cursor_open_chat · Vscode MCP: Risk & Policy

WHAT IT DOES

What cursor_open_chat does on Vscode

AI agents invoke cursor_open_chat to trigger actions in Vscode. 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 cursor_open_chat needs a policy

This tool triggers an external operation within the Cursor IDE by opening UI panels (chat, composer, or agent). It causes a side effect in the application state rather than simply reading data, and opening an agent panel could initiate AI agent workflows. It's not purely destructive or financial, but it does execute an IDE action with potential downstream effects depending on what is launched.

From the tool's definition Open a new chat, composer, or agent panel in Cursor

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

cursor_open_chat Rate-limited

cursor_open_chat 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": {
    "cursor_open_chat": {
      "limits": [
        {
          "counter": "cursor_open_chat_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 Vscode, so you can run agents against it safely.

FAQ

Questions about cursor_open_chat

What does the cursor_open_chat tool do? +

Open a new chat, composer, or agent panel in Cursor. It is categorised as a Execute tool in the Vscode MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on cursor_open_chat? +

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

What risk level is cursor_open_chat? +

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

Can I rate-limit cursor_open_chat? +

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

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

cursor_open_chat is provided by the Vscode MCP server (kloutdevs/vscode-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.