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 the community-maintained 0.6.0 release. DeepSeek Harness is currently a Developer Preview, and this extension pins the official @deepseek-ai/[email protected] package (Typert Remote protocol).
Runtime upgrade: Harness now uses session format V3. Supported older logs are migrated on resume into a new generation while their original files are preserved. Old runtimes cannot read the new V3 generation; back up ~/.dsh/vscode/harness-home before upgrading, and do not downgrade an active profile. Third-party plugins using the removed ctx.agent or runtime Inbox APIs need their own compatibility updates. The extension keeps its native VS Code interface rather than embedding the official Web UI.
Older installations can leave ordinary package directories where Harness expects managed links. Startup and plugin installation now recover these shared profiles/node_modules conflicts automatically: incompatible entries move into module-fallback-backup-* inside the Harness home, then Harness rebuilds its links. Backup paths appear in the output log. Existing links/proxies, profiles/web plugins, conversation history and credentials are preserved; no terminal cleanup is required for this conflict. Permission or sharing errors stop recovery without deleting the original data.
Features
- Native VS Code workbench — all interaction happens in the sidebar; the local Harness Gateway exposes only the loopback API transport, while the official WebUI is neither served nor embedded.
- Shared local history — the bundled runtime and an independently installed official DSH can read the same saved conversations. Installing the official CLI is optional; credentials and plugin profiles stay separate.
- Detachable workbench — open the same synchronized conversation UI in an editor-area panel and move it to another VS Code window when more space is needed.
- Complete session workflow — persistent history, create, switch, rename, fork, resume, archive/restore, export, and import sessions (official DSH ZIP, ChatGPT export ZIP, and other agent transcripts via
dsh-chat-import); changing the DSH mode opens a fresh session in the new mode and carries the previous context as a hidden digest attached to your next message.
- Streaming Markdown — headings, lists, tables, code blocks, copy controls, safe external links, and clickable workspace file references.
- Stable incremental rendering — streamed updates preserve disclosure state and the reader's scroll position.
- Progressive reasoning timeline — nodes appear as thinking steps arrive, connecting only existing steps within the same turn. Completed turns retain their timeline inside the expandable process section.
- Session auto-naming — new conversations get a concise single-line title derived from the first message; manual renames are never overwritten.
- Per-turn file changes — edited-file cards stay with their own conclusions, including restored history and follow-up conversations.
- Compact completed turns — reasoning, tool calls and interim updates fold into a duration row; the final answer and file changes remain visible.
- Reader-friendly streaming — while a turn streams you can scroll up through earlier messages freely; auto-follow yields to your scroll and only resumes at the very bottom. The finished conclusion is set off by a divider between the thinking and the final answer (or above the message when there is no thinking).
- DeepSeek Harness-native reasoning — thinking is presented in a native reasoning block that opens as deltas stream, follows the newest content, and collapses to a summary row once the block completes.
- Editor context — selected code appears as a removable context card; type
@ to fuzzy-search and attach workspace files without leaving the composer.
- 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 / low / high / max reasoning effort, and four official Agent Presets.
- Token usage — see current input and output token counts in the composer.
- Native DSH plugin center — search a curated catalog, filter by category, inspect installed plugins, or install an npm/GitHub/local/tarball package.
- Automatic localization — follows the VS Code display language with English and Simplified Chinese support.
- Zero-deployment runtime — official
dsh, pnpm, 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.
Interface preview
Screenshots use the 0.5.9 workbench UI with a demonstration conversation and no private account data. This README shows the English interface; the Chinese README shows the localized interface. Select an image to view it at full resolution.
|
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| 0.5.9 workbench — compact turn process, final answer and per-turn file changes |
Flash / Pro, four DSH modes and the effort slider |
Installation
- Download the VSIX matching your platform from Releases.
- Open the VS Code Extensions view (
Cmd/Ctrl+Shift+X).
- Select
... → Install from VSIX... and choose the downloaded file.
- Reload the VS Code window when prompted.
For example, an Apple Silicon Mac requires the darwin-arm64 package.
Quick start
- Open the project you want to work on.
- Select the DeepSeek Harness icon in the Activity Bar.
- Open Connection settings and configure DeepSeek Official or add a relay source. You can also run
DeepSeek Harness: Set API Key for the official source.
- Describe your task in the composer and send it.
No Harness install or start command is required.
Shared history with official DSH
The extension still ships and starts its own tested Harness/Node runtime. A separately installed CLI is not required and is not substituted automatically. On the same machine and OS user account, both backends use the official history location by default:
| Platform |
Shared history home |
| Windows |
%USERPROFILE%\.dsh |
| macOS |
~/.dsh |
| Linux |
~/.dsh |
An inherited DSH_HOME takes precedence. If official DSH uses another home, set the application-level deepseekHarness.historyHome to that same absolute path. Only sessions/ and attachments/ are shared. The extension's credentials, plugin profile and caches remain under ~/.dsh/vscode/harness-home; archive/pin state and UI filters remain separate. VS Code uninstall does not remove the shared history.
Old private/globalStorage histories are migrated through the official session codecs, with the original logs retained. Equal records are not duplicated; a strictly newer compatible prefix is appended only with write ownership. Diverged histories, or newer copies whose destination is busy, become separately named “VS Code history” forks. Completed imports are journaled, so reopening the extension does not keep duplicating them. In-use old sources are deferred; if migration fails, the extension keeps its previous private history for that launch and shows a warning instead of silently starting with an empty migrated store.
Open the VS Code history panel to refresh its list; refresh the official Web UI page to discover externally created history. VS Code filters by the current project, while official DSH may show worktree sessions under their own workspace or as ungrouped sessions. This shares saved history, not another process's transient token stream. Kernel locks prevent simultaneous writes to one session: close the owning backend before continuing on the other side, or create a fork. Model credentials and installed plugins are configured independently.
Both runtimes must support the same log format (this build uses V3, DSH 0.1.5-alpha.1). An older official CLI cannot read new V3 logs and must be updated to use this sharing feature; original V2 files are retained, but are not a downgrade-sync mechanism. This is not cloud, cross-device, or Windows/WSL cross-kernel synchronization; do not run live shared stores through a network/sync drive. Back up both the shared home and the old private home before a major runtime upgrade.
DSH plugins
Open the ⊞ Plugins button in the workbench header to browse repositories read directly from the dsh-plugin GitHub topic. Results are merged with Awesome DSH Plugin metadata for curated categories, localized descriptions, and npm install specs. The Installed tab also accepts one package spec directly, including an npm package, github:owner/repository, a local path without shell metacharacters, or a tarball URL.
0.5.9 plugin center — built-in catalog example, not the complete live GitHub marketplace
The extension uses the official dsh plugin --profile web add/remove workflow. Plugin profile files live under ~/.dsh/vscode/harness-home/profiles/web; Harness is stopped while pnpm changes that profile and is then restarted automatically. The bundled pnpm means no system package manager is required.
Host tools, policies, and runtime services contributed by a plugin work in this extension. A plugin may also contain client UI designed specifically for the upstream DSH browser application; those UI contributions cannot be rendered generically by this native VS Code workbench and are marked Official Web UI.
Marketplace cards classify known entries as Agent compatible, Agent works · Web UI unavailable, or Official Web UI only. UI-only themes and layout extensions cannot affect the native workbench, so their install button is disabled. GitHub-only entries without curated metadata are marked Compatibility unknown until their installed manifest can be inspected.
Configuration
| Setting |
Default |
Description |
deepseekHarness.model |
deepseek-v4-flash |
Default model for new sessions |
deepseekHarness.reasoningEffort |
high |
off / low / high / max |
deepseekHarness.agentPreset |
standard |
Default Agent Preset for new sessions |
deepseekHarness.provider |
deepseek-official |
Default source selected from the extension's Connection settings panel |
deepseekHarness.permissionMode |
workspace-write |
read-only / workspace-write / danger-full-access |
deepseekHarness.autoAttachSelection |
true |
Automatically attach the active editor selection when sending |
Provider endpoints and write-only credential references are managed through the bundled Harness settings and credentials services. API keys are stored in the extension's private Harness home, are never returned to the webview, and are not written to project-level .vscode/settings.json. Legacy deepseekHarness.apiKey, baseUrl, and providers values are imported once and then removed.
Use the Connection settings panel to add, edit, test, or remove DeepSeek relay sources. Custom sources are registered live through the upstream llm-pi-ai adapter and expose the same Flash/Pro choices in the model panel.
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: Open Workbench in New Window |
Open the detachable editor-area 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 |
DeepSeek Harness: Import Sessions |
Import a DSH ZIP, ChatGPT ZIP, or other agent transcripts |
System notifications
Completed foreground and background work now uses native Windows/macOS notifications, not VS Code's in-window completion popup. Duplicate idle events, child-agent completions and Stop actions from this extension do not generate extra alerts. Queued prompts notify when the agent becomes idle after finishing the queue; opening old history does not replay notifications. Approval/question prompts remain unchanged.
User settings (effective immediately, without restarting Harness):
"deepseekHarness.systemNotifications.enabled": true,
"deepseekHarness.systemNotifications.sound": false,
"deepseekHarness.systemNotifications.includeConversationTitle": false
Run DeepSeek Harness: Test System Notification from the Command Palette to test without an API request. Errors are recorded under DeepSeek Harness: Show Logs; there is no in-window fallback. Notifications never contain reply text or detailed errors; enabling titles may expose them on the lock screen.
- macOS: uses the system AppleScript notification service. Allow notifications/banners for the sender shown in System Settings → Notifications (it may appear as Script Editor/osascript, not a separate Harness app).
- Windows: uses Windows PowerShell and Windows Toast with the running VS Code product's AppUserModelID (including Insiders). Use an installed VS Code with its registered Start menu shortcut; portable/custom builds without a registered identity may not show notifications. No registry changes, administrator access or extra notification package is required.
- OS permissions, Focus/Do Not Disturb and enterprise policies can suppress banners even after successful submission. This feature currently requires a local desktop extension host; Linux, Remote SSH, WSL, containers and browser-hosted VS Code are not supported. Disconnected runs are not replayed after reconnection.
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.
- Plugin catalog JSON is fetched by the Extension Host, validated into a narrow UI data model, and rendered with
textContent.
- 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.
- Third-party DSH plugins are trusted Extension Host dependencies: they run outside the Agent sandbox. Review their source before installation.
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.
A native VS Code extension that brings the DeepSeek Harness coding agent into the editor's sidebar, with session management, streaming Markdown, slash commands, and a plugin center, all without needing a separate WebUI or Harness setup.