DeepSeek adds chat-built custom plugins to Harness Creator Mode

DeepSeek has added a Creator Mode to Harness that can create and install custom plugins from conversational requests. It gives users a guided way to add tools, skills and interface elements to the open-source agent platform.

DeepSeek says users can install existing plugins or create new ones through chat. In the company’s demonstration, Harness responds to a request for a Pomodoro timer by loading a plugin-development skill, writing package and client files, installing the bundle through its plugin manager, editing the client code and checking the live plugin state.

According to DeepSeek, the timer was built, installed and verified in 5 minutes and 24 seconds. The result comes from the company’s demonstration and has not been independently reproduced.

Creator Mode works through Harness’s existing plugin system rather than a separate generator. In DeepSeek’s architecture note, the company says the mode enables the plugin_manager tool. The agent creates package files and Loader YAML patches in the workspace, then passes them to install_bundle. The existing manager handles installation, enablement and profile locking. Hot-module replacement can activate new bundles on live profiles, while installed package replacement requires a restart.

DeepSeek says plugin management requires full-access mode or approval for a call because a profile change can load code with host permissions and affect other sessions. Installed changes can persist across restarts. Approval covers the management operation rather than permanently increasing the session’s permissions.

Users can enter the same creation flow from Settings or the Add plugin menu on the Plugins page, according to DeepSeek’s preset documentation. Both entries start a Creator Mode task using the Cordis preset. The settings page displays preset configuration but does not directly edit it.

The feature expands DeepSeek Harness, which the company describes as an open-source agent harness in developer preview with an everything-is-a-plugin architecture powered by Cordis. It is distinct from DeepSeek’s superagent coding prototype, a Harness bundle for work on a single GitHub repository that DeepSeek labels research code rather than an official product or production-ready software.

DeepSeek’s product page does not give Creator Mode a publication timestamp or versioned release date. The repository’s implemented persistent-plugin-management note is dated September 16, so the available evidence does not establish when the feature first became available.