DeepSeek Harness for VS Code

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A native VS Code coding-agent extension powered by DeepSeek Harness. Install the platform-specific VSIX and start working—there is no upstream repository to clone, no Node/npm setup, and no local Harness deployment to manage.

This is a community-maintained 0.4.2 release. DeepSeek Harness is currently a Developer Preview, and this extension pins the official @deepseek-ai/dsh@0.1.0-rc.6 package.

Features

• Native VS Code workbench — all interaction happens in the sidebar; the official WebUI is never embedded.
• Complete session workflow — persistent history, create, switch, rename, fork, and resume sessions.
• Streaming Markdown — headings, lists, tables, blockquotes, inline formatting, code blocks, copy controls, and safe external links.
• Stable incremental rendering — streamed updates preserve disclosure state and the reader's scroll position.
• Editor selection context — automatically attach selected code or insert it explicitly with the “⬒ Selection” button.
• Slash commands — use official Harness commands plus /model, /reasoning, and /preset extension commands.
• Harness-native capabilities — reasoning, tool calls, approvals, structured questions, Todos, Skills, Goals, Plan mode, and background jobs.
• Model and agent controls — DeepSeek V4 Flash / Pro, off / high / max reasoning effort, and four official Agent Presets.
• Token usage — see current input and output token counts in the composer.
• Automatic localization — follows the VS Code display language with English and Simplified Chinese support.
• Zero-deployment runtime — official dsh and standalone Node 22.22.3 are bundled in each platform VSIX and managed by the extension.

Open the workbench with Ctrl+Alt+H on Windows/Linux or Cmd+Alt+H on macOS.

Installation

1. Download the VSIX matching your platform from Releases.
2. Open the VS Code Extensions view (Cmd/Ctrl+Shift+X).
3. Select ... → Install from VSIX... and choose the downloaded file.
4. Reload the VS Code window when prompted.

For example, an Apple Silicon Mac requires the darwin-arm64 package.

Quick start

1. Open the project you want to work on.

2. Add your DeepSeek API Key to the VS Code user settings.json:

   {
     "deepseekHarness.apiKey": "sk-your_DeepSeek_API_Key"
   }
   

   You can also run DeepSeek Harness: Set API Key; the extension writes to the same user setting.

3. Select the DeepSeek Harness icon in the Activity Bar.

4. Describe your task in the composer and send it.

No Harness install or start command is required.

Configuration

Setting	Default	Description
deepseekHarness.apiKey	empty	DeepSeek API Key stored as plain text in user settings.json with machine scope
deepseekHarness.model	deepseek-v4-flash	Default model for new sessions
deepseekHarness.reasoningEffort	high	off / high / max
deepseekHarness.agentPreset	standard	Default Agent Preset for new sessions
deepseekHarness.provider	deepseek-official	Harness model-provider route
deepseekHarness.baseUrl	empty	Optional API base URL
deepseekHarness.permissionMode	workspace-write	read-only / workspace-write / danger-full-access
deepseekHarness.autoAttachSelection	true	Automatically attach the active editor selection when sending

The API Key is never written to project-level .vscode/settings.json, but it is stored as plain text in your local user settings. Do not commit or share a settings file containing the key.

Automatically attached selections are limited to 16 KB and are truncated when necessary. If the same file selection is already embedded manually, the host will not attach it again.

Commands

Command	Description
DeepSeek Harness: Open Workbench	Open the sidebar workbench
DeepSeek Harness: Reload Workbench	Restart the runtime and reconnect
DeepSeek Harness: Set API Key	Save the API Key
DeepSeek Harness: Clear API Key	Clear the API Key
DeepSeek Harness: Show Logs	Open diagnostic logs

Localization

English is the default language, and a Simplified Chinese language pack is included. Manifest contributions, settings, extension-host prompts, errors, and the full chat workbench follow the VS Code display language. After changing the display language, run Developer: Reload Window.

Security and privacy

• The Harness Gateway listens only on a random 127.0.0.1 port.
• The Webview uses a strict CSP and loads no remote scripts or iframes.
• Raw Markdown HTML is disabled, and rendered markup is sanitized through a DOMPurify allowlist.
• Remote Markdown images are disabled; http(s) links are validated again by the extension host.
• File and command access is controlled by permissionMode and Harness approval policies.
• The API Key is never sent to the Webview or written to extension logs.

Platform support

There is one extension ID and one Marketplace product. Platform-specific VSIX files are required because the bundled Node, PTY, and sandbox packages contain native binaries:

• macOS: darwin-arm64, darwin-x64
• Linux: linux-arm64, linux-x64
• Windows: win32-arm64, win32-x64

The current hosted GitHub Actions matrix builds darwin-arm64, linux-arm64, linux-x64, and win32-x64. Other architectures require a self-hosted runner or local packaging.

Development and packaging

npm install
npm run check-types
npm run lint
npm test
npm run compile
npm run package

npm run package creates a VSIX for the current operating system and CPU architecture. npm ci executes lifecycle scripts required by native dependencies, so build only trusted commits and lockfiles.

All project commit messages use English. See docs/ARCHITECTURE.md for the architecture and security boundaries.

License

Extension code is licensed under the MIT License. Licensing details for DeepSeek Harness, Node.js, and other dependencies are available in THIRD_PARTY_NOTICES.md and the license files shipped with each dependency.