claude-to-dsh

Let Claude Desktop (or any MCP client) drive DeepSeek Harness — and watch the work happen in the Harness sidebar as it runs.

Claude Desktop ──MCP/stdio──▶ claude-to-dsh ──loopback HTTP──▶ Harness window
                                                                   └─▶ new Session
                                                                       (sidebar visible)

Why this exists

DeepSeek Harness ships two ways to drive it from outside a process, and neither fits an MCP client:

The headless route works, but its sessions land in ~/.dsh/sessions/--<cwd>--/, which the GUI never scans. The sidebar reads the workspace registry held in the running process's memory, and no outside process can write to it — the browser API is fenced by a per-process launch token.

So this project has two halves:

1. A Host plugin that runs inside the Harness process and creates the session through that process's own sessionController, which attaches it to a workspace. Result: a real session, in the sidebar, with history.

2. An MCP server that Claude Desktop launches, which forwards tasks to that plugin over loopback.

If the plugin is not running, the MCP server falls back to dsh --profile headless, so the tool still works — the answer just says ran headless (not shown in the Harness GUI).

Related MCP server: dsh-mcp

Install

1. Add the plugin to your Harness profile

From npm (after it is published):

dsh plugin --profile desktop add claude-to-dsh

Straight from GitHub:

dsh plugin --profile desktop add github:wang53333/claude-to-dsh

From a local checkout:

dsh plugin --profile desktop add file:C:\path\to\claude-to-dsh

Use --profile web instead of desktop if you run the browser profile. There is nothing else to edit by hand: the command appends the package to the profile's dsh.profile.bundles, and the bundle's own cordis.patch.yml supplies the mount row.

{ "dsh": { "profile": { "bundles": ["@deepseek-ai/dsh-base", "@deepseek-ai/dsh-web-app", "claude-to-dsh"] } } }

2. Point Claude Desktop at the MCP server

Edit claude_desktop_config.json (%APPDATA%\Claude\ on Windows, ~/Library/Application Support/Claude/ on macOS; Microsoft Store builds redirect this into %LOCALAPPDATA%\Packages\Claude_*\LocalCache\Roaming\Claude\):

{
  "mcpServers": {
    "dsh": {
      "command": "npx",
      "args": ["-y", "claude-to-dsh"]
    }
  }
}

Without npm, point at the checkout instead:

{
  "mcpServers": {
    "dsh": {
      "command": "node",
      "args": ["C:\\path\\to\\claude-to-dsh\\bin\\mcp-server.js"]
    }
  }
}

3. Restart DeepSeek Harness, then Claude Desktop

The plugin mounts at Harness startup; the MCP server starts when Claude does. Order matters — restart Harness first.

Use it

Ask Claude:

Use dsh_task to check how much free space is on the C: drive and list the five largest directories.

To keep a conversation going, pass the returned session_id back on the next call. The tool description already tells Claude to write self-contained instructions and to reuse the session id, but say so explicitly if it forgets.

Verify

# Plugin mounted? The file appears when a Harness window with the plugin starts.
cat ~/.dsh/mcp/endpoint.json

# MCP server alive? It logs every call here.
tail -f ~/.dsh/mcp/server.log

In Claude Desktop, ask "list your tools" — dsh_task should be there. Every result ends with either ran in the open Harness window (visible) or ran headless (not shown in the Harness GUI).

How it works

• The plugin binds an HTTP listener on 127.0.0.1:0 (OS-assigned port) and writes {port, token, pid} to <DSH_HOME>/mcp/endpoint.json with 0600 permissions.

• A token of 24 random bytes is minted per boot, so a fixed port is unnecessary and a hostile local process cannot guess the credential.

• POST /task with x-dsh-bridge-token calls sessionController.create({ workspaceId }) then sessionController.prompt(...), and polls the derived message list until the last message is an assistant message and the log has been quiet for 1.5 s.

• GET /health and GET /debug?session=<id> exist for diagnostics.

Security

The plugin grants an MCP client the same power the Harness agent already has in that window: your shell, your files, your credentials. Treat it accordingly.

• Listener binds loopback only; no LAN exposure.

• Every request must present the per-boot token from endpoint.json.

• The endpoint file is written 0600 on POSIX; on Windows it inherits your user profile's ACLs.

• Any process running as you can read that file and therefore drive the bridge. If that is unacceptable, do not install this.

Known limitations

• Approval prompts block. If a task triggers a tool the Harness policy gates (for example writing outside the session workspace), the approval card appears in the GUI and the HTTP call waits for a human. Open that session to approve; otherwise the turn times out.

• One Harness window per DSH_HOME. Each window overwrites endpoint.json, so the MCP server talks to the most recently started one.

• Separate session, not your current chat. Delegated turns never inherit the conversation you are having in the GUI; put context in task.

• Host route needs the plugin mounted. Without it the headless fallback runs, which is functional but invisible — and headless must be able to authenticate (see below).

• Headless fallback needs credentials. The shipped headless profile routes to deepseek-official, which requires DEEPSEEK_API_KEY. The account login used by the desktop app is not available to a plain CLI process.

Compatibility

Built against DeepSeek Harness 0.2.1-rc.2. Uses only public services (sessionController, workspaceRegistry, sessions) and Node built-ins — no runtime dependencies, no build step.

Uninstall

dsh plugin --profile desktop remove claude-to-dsh

Then delete the mcpServers.dsh entry from your Claude Desktop config.

License

MIT