[Bug]: TypeError: Cannot read properties of null (reading 'accept') during connectDevtools()

[nickbanana]

Version

1.3.0

Steps to reproduce

import { Stagehand } from "@browserbasehq/stagehand";
import { endpointURLString } from "@cloudflare/playwright";
import { z } from "zod";

export default {
  async fetch(request, env) {
    const stagehand = new Stagehand({
      env: "LOCAL",
      localBrowserLaunchOptions: { cdpUrl: endpointURLString(env.BROWSER) },
      modelName: "google/gemini-3-flash-preview",
      modelClientOptions: { apiKey: env.GOOGLE_API_KEY },
      verbose: 1,
    });

    await stagehand.init(); // throws here in production
    ...
  },
} satisfies ExportedHandler<Env>;

put above code into worker

Expected behavior

stagehand.init() resolves and stagehand.page is usable, same as under wrangler dev.

Actual behavior

{
  "category": "init",
  "message": "connecting to local browser via CDP URL",
  "level": 1,
  "auxiliary": {
    "cdpUrl": {
      "value": "http://fake.host/v1/devtools/browser?browser_binding=BROWSER",
      "type": "string"
    }
  }
}
{
  "message": "Error in init:",
  "level": 0,
  "auxiliary": {
    "error": {
      "value": "TypeError: Cannot read properties of null (reading 'accept')",
      "type": "string"
    }
  }
}
{
  "message": "The browser context is undefined. This means the CDP connection to the browser failed. If running locally, please check if the browser is running and the port is open.",
  "level": 0
}

Additional context

local isn't affected, but prod environment can't use stagehand

Environment

- `wrangler`: 4.107.0
- `@cloudflare/playwright`: 1.3.0
- `@browserbasehq/stagehand`: 2.5.9
- `wrangler.jsonc`:
  
  {
    "compatibility_date": "2026-07-09",
    "compatibility_flags": ["nodejs_compat"],
    "browser": { "binding": "BROWSER" },
    "alias": { "playwright": "@cloudflare/playwright" }
  }
  
- Workers plan: Paid (Browser Rendering requires it)