Fix remaining lsof crashes in sandbox environments

Added isInSandbox() helper to mcp-server/app/mcp/tools.ts and
wrapped all lsof-dependent code paths to skip in sandbox:
- restart_dev_server MCP tool now returns error in sandbox
- killPortProcess functions in dev-environment.ts skip lsof

The lsof utility doesn't exist in Vercel Sandbox, Docker containers,
and other constrained environments.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: elsigh

mcp-server/app/mcp/tools.ts

@@ -9,6 +9,19 @@ import { WebSocket } from "ws"
 
 const execAsync = promisify(exec)
 
+/**
+ * Detect if we're in a sandbox environment (Vercel Sandbox, Docker, etc.)
+ * where lsof and other system utilities may not be available.
+ */
+function isInSandbox(): boolean {
+  return (
+    process.env.VERCEL_SANDBOX === "1" ||
+    process.env.VERCEL === "1" ||
+    existsSync("/.dockerenv") ||
+    existsSync("/run/.containerenv")
+  )
+}
+
 // Tool descriptions
 export const TOOL_DESCRIPTIONS = {
   fix_my_app:
@@ -3902,6 +3915,19 @@ export async function restartDevServer(params: {
     // Fallback: Use dev3000's own restart mechanism
     logToDevFile("Restart Dev Server: Using dev3000 restart mechanism")
 
+    // In sandbox environments, lsof doesn't exist - skip process killing
+    if (isInSandbox()) {
+      logToDevFile("Restart Dev Server: Skipping lsof-based kill in sandbox environment")
+      return {
+        content: [
+          {
+            type: "text",
+            text: `⚠️ **RESTART NOT SUPPORTED IN SANDBOX**\n\nDev server restart is not supported in sandbox environments (Vercel Sandbox, Docker containers).\n\nThe \`lsof\` utility needed for process management is not available.\n\n💡 If running in Vercel Sandbox, the dev server is managed by the sandbox infrastructure.`
+          }
+        ]
+      }
+    }
+
     // Kill processes on the app port
     const killCommand = `lsof -ti :${appPort} | xargs kill 2>/dev/null || true`
     logToDevFile(`Restart Dev Server: Executing kill command: ${killCommand}`)

src/dev-environment.ts

@@ -2406,8 +2406,12 @@ export class DevEnvironment {
       console.log(chalk.yellow(`🛑 Shutting down ${this.options.commandName} due to critical failure...`))
     }
 
-    // Kill processes on both ports
+    // Kill processes on both ports (skip in sandbox - lsof doesn't exist)
     const killPortProcess = async (port: string, name: string) => {
+      if (isInSandbox()) {
+        console.log(chalk.gray(`ℹ️ Skipping ${name} port kill in sandbox environment`))
+        return
+      }
       try {
         const { spawn } = await import("child_process")
         const killProcess = spawn("sh", ["-c", `lsof -ti:${port} | xargs kill -9`], { stdio: "inherit" })
@@ -2605,8 +2609,13 @@ export class DevEnvironment {
     // Now we keep .mcp.json, .cursor/mcp.json, and opencode.json configured
     // for the next dev3000 run, providing a better developer experience
 
-    // Kill processes on both ports
+    // Kill processes on both ports (skip in sandbox - lsof doesn't exist)
     const killPortProcess = async (port: string, name: string) => {
+      // Skip lsof-based kill in sandbox environments
+      if (isInSandbox()) {
+        this.debugLog(`Skipping ${name} port kill in sandbox environment`)
+        return
+      }
       try {
         const { spawn } = await import("child_process")