Backchat

DEEPSEEK HARNESS + BACKCHAT

Use DeepSeek Harness in Backchat.

Install the ACP adapter, sign in without placing an API key in Backchat, and start a DeepSeek session in about ten minutes.

Download BackchatView adapter source
  • 10 minute setup
  • Node.js 22.15+ for manual install
  • macOS · Windows · Linux

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

    Complete terminal setup

    Choose the key/setup action, then Open terminal setup. The adapter runs dsh-acp login and saves the credential in the harness credential store.

  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.

Your API key stays in DeepSeek Harness's own credential store. Backchat launches the adapter but does not copy the key into its settings.

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.

Terminal
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. Save a key from Backchat's terminal setup, with dsh-acp login, or in dsh web under Settings → Models.

For ephemeral environments, DEEPSEEK_API_KEY and optional DEEPSEEK_BASE_URL can be passed to the process. Do not commit either value or place it in a public command example.

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.

Terminal
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
Reopen the setup action or run dsh-acp login. Finish the interactive prompt, 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.
Open an adapter issue

Ready to start a DeepSeek session?

Install Backchat, open Settings → Agents, and follow the managed path above.

Download BackchatBack to Backchat