debug_startSession

THE RISK

High Risk

Why debug_startSession needs a policy

Starting a debug session is fundamentally an Execute operation because it launches and runs code whose behavior depends on the configuration arguments. While not immediately Destructive, the blast radius is high: an AI agent could trigger execution of arbitrary code, perform side effects, access sensitive data during execution, or cause system resource consumption.

From the tool's definition Tool explicitly initiates a debug session that triggers code execution via a launch configuration. Sibling tools like debug_continueExecution, debug_pauseExecution, and debug_evaluateExpression confirm this is an active execution environment where arbitrary…

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

POLICY

How to control debug_startSession

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

policy.json

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

debug_startSession 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 MCP Server for VS Code — 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 MCP Server for VS Code tools

Destructive debug_clearBreakpoints Remove all breakpoints from the workspace Execute debug_evaluateExpression Evaluate an expression in the current debug context (REPL/watch functionality). Test hypot Execute debug_stepOver Step over the current line of code (execute current line without entering functions) Execute debug_stopSession Stop the current debug session Execute debug_continueExecution Continue execution from the current breakpoint or paused state Execute debug_pauseExecution Pause the running debug session at the current execution point Execute debug_stepInto Step into function calls on the current line Execute debug_stepOut Step out of the current function and return to the caller

All 25 MCP Server for VS Code tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in MCP Server for VS Code → 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 debug_startSession

What does the debug_startSession tool do? +

Start a debug session using a configuration from launch.json. Launch debugging instantly - no need to navigate to the debug panel. It is categorised as a Execute tool in the MCP Server for VS Code MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on debug_startSession? +

Register the MCP Server for VS Code MCP server in PolicyLayer and add a rule for debug_startSession: 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 Server for VS Code. Nothing to install.

What risk level is debug_startSession? +

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

Can I rate-limit debug_startSession? +

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

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

debug_startSession is provided by the MCP Server for VS Code MCP server (malvex/mcp-server-vscode). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Server for VS Code tool call.

Start from MCP Server for VS Code, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →