[Feature]: Support extensions in the integrated browser for testing

[pantharshit007]

Problem

When testing a web app in T3 Code’s integrated browser, there is no way to use browser extensions as part of the test workflow. This makes extension-dependent behavior and extension-based debugging or request modification harder to test without switching to a separate browser.

Proposed capability

Allow users to install or load browser extensions in the integrated browser and use them during testing. For example, a user could enable Requestly to redirect requests, modify headers, or mock API responses, then inspect the resulting app behavior in the same integrated browser.

It would be useful if extensions could remain available across test steps and be enabled or disabled when needed.

Why this would help

This would make it possible to test realistic browser behavior and extension-assisted scenarios without leaving T3 Code’s integrated browsing workflow.

[lukasbxy]

I'd like to add an extension-development use case to this request, and I'd be happy to contribute a PR once we agree on the direction and scope.

I regularly develop Chrome extensions. I'd like the agent to build and test them inside T3 Code, with the same tool access it has to the preview browser today. The extension lifecycle and debugging need to be available through agent tools so the agent can complete the development loop without me manually loading extensions or switching to another browser.

The workflow

The agent should be able to:

• Load an unpacked extension from the project and list loaded extensions, their IDs, and status.
• Reload it after code changes and a build, and enable, disable, or remove it.
• Open and interact with its popup and options page, and test its content scripts on a target page.
• Inspect extension logs and errors, including its background page or Manifest V3 service worker, and access the relevant debugging targets.
• Use the preview browser's existing interaction and screenshot tools to check the result.

The loop would be: edit code → build → reload the extension → interact with it → inspect failures → fix and repeat. Full agent operation is the core requirement for me, including cleanup when testing is done.

A possible first scope

I'd start with unpacked local extensions in the desktop preview browser, scoped to a browser profile, with the agent tools needed for the workflow above. Chrome Web Store installation could stay outside that first version.

Electron's partial support for Chrome extension APIs is something we would need to establish up front, especially for Manifest V3 background workers and extension UI. I'd want us to agree on a tested set of supported capabilities and make unsupported cases explicit, rather than promise compatibility with every Chrome extension.

Before starting a PR

Would you be open to a contribution with this scope? Are there parts you would change, or technical checks you'd want to see before approving the direction?

I'm happy to help with a focused compatibility investigation first, then contribute the implementation, tests, and a recorded example of the agent completing the development loop.