Use DeepSeek Harness in Backchat.

RECOMMENDED PATH

Let Backchat manage the adapter.

Backchat ships a registry entry for DeepSeek Harness. You do not need to edit JSON or add a custom command for the standard setup.

1. 01

   Open agent settings

   Launch Backchat, open Settings → Agents, then find DeepSeek Harness at the top of Registry.

2. 02

   Install the adapter

   Choose Install. Backchat installs @openma/deepseek-harness-acp into its managed ACP tools directory and enables it.

3. 03

   Save an API key

   Choose Sign in, then pick API Key, Custom model gateway, or Browser. API key and gateway send `_meta` through ACP authenticate; Browser opens a local page. Backchat does not keep the secret.

4. 04

   Start a real session

   Create a new chat, choose a project and DeepSeek Harness, then use /status to verify the active model, mode, and credential state.

MANUAL INSTALL

Prefer your own global command?

Use this path when you want dsh-acp available outside Backchat. The package requires Node.js 22.15 or newer. After installing, return to Settings → Agents and choose Refresh.

node --version
npm install -g @openma/deepseek-harness-acp
dsh-acp login

AUTHENTICATION

One credential store, three safe entry points.

dsh-acp reuses $DSH_HOME/.credentials.yaml—the same mode-600 file used by the dsh Web UI. In Backchat, choose API Key, Custom model gateway, or Browser. You can also save a key with dsh-acp login or in dsh web under Settings → Models.

EXISTING DSH USERS

Attach the ACP bridge to a dsh profile.

If your models, presets, skills, and settings already live in dsh, install the adapter as a profile plugin and point a Backchat custom agent at that profile.

npm install -g @deepseek-ai/dsh
dsh web
dsh plugin --profile acp add -w @openma/deepseek-harness-acp

Then add a custom agent in Settings → Agents

ID

deepseek-profile

Name

DeepSeek Harness (profile)

Command

dsh

Arguments

--profile acp

VERIFY THE CONNECTION

What should work after setup

• Streaming responses and reasoning
• Tool calls with file diffs and terminal output
• Read-only, workspace-write, and danger-full-access modes
• Live model and reasoning-effort choices
• Slash commands, skills, sessions, plans, usage, and MCP servers

Sessions start in workspace-write. Use danger-full-access only in disposable checkouts or containers.

TROUBLESHOOTING

Four checks solve most setup failures.

DeepSeek Harness is not listed

Open Settings → Agents and choose Refresh. For manual installs, confirm dsh-acp is on PATH with dsh-acp --help.

Install reports an unsupported Node version

Run node --version. The current adapter package requires Node.js 22.15 or newer.

The row says Auth needed

Open Sign in, save an API key, or run dsh-acp login. Then start a new session.

A dsh profile does not load

Run dsh --profile acp once in a terminal, then verify the custom Backchat command is dsh with arguments --profile acp and that both processes share DSH_HOME.