Visual Studio Code Extension

[yanickfischer]

Great work on the dsh, even though it's still early I love the product - thank you developers & maintainers!

I am writting you to request: official VS Code extension that runs DeepSeek Harness in a side panel, with the same seamless feel as Anthropic's Claude Code extension for VS Code.

There is a similar topic open, but it has no replies and the tool described there is not an official deepseek product:
#3418

Why

Today the Harness has no way to work inside the editor. The Web UI and Desktop app run separately from VS Code, and "Open In…" only launches the editor on the workspace.

ACP isn't a route either. The 2026-07-23 design note makes it automation-only on purpose: no diffs, plans, terminals or client file access. That's a sensible boundary, so this request is for a dedicated editor client, not for reviving the old ACP bridge.

Many of us live in VS Code all day. Switching to a browser tab for every agent turn loses the editor context: open file, selection, diagnostics and inline diff review.

What it should feel like

The reference is the Claude Code extension for VS Code. It feels native because the agent sees what you see and every change is reviewed where you code.

Area | Claude Code today (reference) | Wanted in the Harness extension -- | -- | -- Entry point | Spark icon in the editor toolbar and Activity Bar, one keyboard shortcut to open or focus | Same: one click or shortcut opens a Harness chat panel in the sidebar or as an editor tab Chat panel | Native-looking chat with streamed replies, collapsible tool calls and thinking | Harness session in a webview themed like VS Code (light/dark), with reasoning and tool cards Editor context | Current file and selection shared automatically; @ mentions files and folders | Open file, selection, and optionally diagnostics passed as context; @ file picker Reviewing edits | Proposed edits open as inline diffs in VS Code's diff view, accept or reject per change | Harness file edits shown as native diffs with accept/reject before they land Permissions | Modes like "ask before edits", "auto-accept edits" and plan mode, switchable in the panel | Harness approval prompts answered in the panel; a mode switch for ask / auto / plan Plans and todos | Plan shown for review before execution; todo progress visible | Harness plans and todos rendered as cards Sessions | Conversation history, resume past sessions, several sessions in tabs | List, resume and run multiple Harness sessions per workspace Model and effort | Model picker in the panel | Provider/model and reasoning-effort picker (e.g. deepseek-v4-pro) Terminal and tools | Shell commands and output visible in the conversation | Harness shell/tool output shown inline; option to open it in a VS Code terminal Setup | Install from Marketplace, sign in, done | Install from Marketplace, point at a local dsh install or bundle it, enter API key once

Minimum useful version: chat panel, editor context, native diff review and approvals. The rest can follow.

How it could be built

Most of the pieces already exist. Two ideas, without claiming to know the internals:

1. Reuse the Web client in a webview. The extension starts or attaches to a local Harness host and renders the existing Web session UI in a VS Code panel. A small editor bridge supplies context (file, selection, diagnostics) and turns file-edit approvals into native diffs.
2. Add a dedicated editor frontend. Similar to how TUI and Web are separate frontends, an "editor" frontend could expose the presentation data an IDE needs, keeping ACP automation-only as decided.

Open questions for the maintainers:

• Is an official IDE client on the roadmap, or would you accept a community extension built on a supported interface?
• Which interface should such a client target so it stays stable across releases?

Happy to test early builds and give feedback.