Introduction

DeepSeek Harness (DSH) uses a plugin-based architecture to extend its core capabilities. In local development environments, browser control usually requires setting up a separate automation profile or results in isolation from the user’s existing session. dsh-b2us-chrome-tool aims to solve this problem by connecting DSH to the user’s existing Chrome session through a Manifest V3 extension and an authenticated loopback WebSocket bridge.

Plugin Overview

This is a secure, local Chrome automation plugin for DSH. It allows an Agent to access and operate authorized tabs in a controlled environment while preventing unauthorized data leakage through context isolation. The plugin is installed and configured using the technical identifier dsh-auto-chrome-tool.

Core Capabilities

The plugin provides the following features for interacting with the browser within a controlled scope:

  • Existing Chrome session: Control user-authorized tabs without creating a new automation profile.
  • Semantic page access: Return limited accessible names, roles, states, and short-lived opaque element references instead of dumping full page source directly.
  • Source-side search: page.find ranks relevant elements at page runtime and then returns the results to the model.
  • Verified locators: page.locator generates CSS/XPath candidates in the live DOM and proves that each candidate uniquely identifies the target element.
  • Page interactions: Supports clicking, exact-name clicking, non-sensitive text input, selection, scrolling, waiting, and structured extraction.
  • Screenshots and network data: Captures screenshots and limited Fetch/XHR metadata or bodies as opaque artifacts with masking, quotas, and expiration.
  • Context isolation: A dedicated Browser Worker receives page data and job-specific tools; the parent Agent receives only limited typed results.
  • Resumable delivery: Browser execution and file delivery are reported separately, so artifact copy failures can be retried without repeating login or submission.
  • Guided setup: Automatically detects Chrome, packages the extension only after DSH approval, and adds a bilingual Harness settings page for status checks, downloads, and pairing.
  • Defense in depth: Restricts the bridge to loopback, validates the extension origin, uses mutual nonce/HMAC authentication, and enforces size, concurrency, timeout, and lifecycle limits.

Installation and Dependencies

Before installation, ensure the environment meets the following requirements:

  • Node.js ^22.19.0 || >=24.0.0
  • Google Chrome 125 or higher
  • DSH version 0.1.2-rc.1
  • Cordis version 4.0.2

Install the plugin with the following command:

dsh plugin --profile web add ./dsh-auto-chrome-tool-0.4.2.tgz

Typical Usage

The plugin provides the following tool interfaces for interacting with pages:

  • page.find: Ranks relevant elements at page runtime.
  • page.locator: Generates CSS/XPath candidates in the live DOM and verifies uniqueness.

Supported page interaction operations include:
* Click
* Exact-name click
* Non-sensitive text input
* Select
* Scroll
* Wait
* Structured extraction

Use Cases and Considerations

  • Use case: This plugin is suitable for local development environments and trusted environments.
  • Security restrictions:
    • The WebSocket server only accepts 127.0.0.1, ::1, or localhost.
    • Pairing requires a token of at least 16 characters.
    • Only chrome-extension:// origins can be authenticated.
    • Arbitrary JavaScript evaluation or arbitrary Chrome DevTools Protocol (CDP) commands are not exposed.
  • Data masking:
    • Password fields only display sensitive and filled states and do not return specific values.
    • Network values such as Cookie, Authorization, API-key, Token, and Session are masked.
    • Screenshot and network body artifacts are subject to quotas and time limits.
  • Permissions and authority:
    • Extension preparation requires approval through the native DSH approval path.
    • The plugin does not edit Chrome profiles, preferences, cookies, password stores, or extension policies.
    • Chrome is the final authority for loading unpacked extensions and granting local network access.

Summary

dsh-b2us-chrome-tool provides a solution for connecting to an existing Chrome session under controlled and secure conditions. Through a Manifest V3 extension and a loopback bridge, it implements features such as semantic access, verified locators, and restricted interaction, making it suitable for DSH development scenarios that require deep integration with a local browser.