dsh-custom-tool

dsh-custom-tool turns extending DeepSeek Harness from shipping a package into filling in a settings form. You can define a tool’s name, parameters, and async JavaScript body in a Monaco editor with TypeScript IntelliSense, and the tool becomes available to the model as soon as it is saved. The model can also persist, list, and remove its own tools during a session, subject to the same validation and ownership rules used by the UI.

The plugin pairs this flexibility with explicit execution boundaries. Each call runs in a fresh worker under timeout, memory, result-size, code-size, and tool-count budgets. Global tools cannot touch the file system, while workspace-scoped tools can only perform file operations confined to the active session workspace, and creating global tools from the model requires explicit user approval.

This is a good fit for users who want to add quick utilities, workflow steps, or workspace file tasks to their agent, and for developers who are comfortable writing small JavaScript tools while keeping model-created extensions under clear guardrails.