DeepSeek Harness: Building and Extending AI Coding Agents Training Course

DeepSeek Harness Introduction

• Defining DeepSeek Harness and its role in the ecosystem.
• The "everything is a plugin" design philosophy.
• Overview of Web UI, CLI, and headless operational modes.

Setup and Initial Execution

• Node.js prerequisites and package installation steps.
• Launching the Web UI using npx.
• Building the application from source code and running it.

Configuring Models

• Configuring the DeepSeek API key.
• Methods for selecting and switching between models.
• Integration with OpenAI-compatible endpoints.

Managing Workspaces and Sessions

• Selecting and navigating between different workspaces.
• Understanding the session composer and conversation dynamics.
• Operations for reading, editing, and generating files.

Executing Coding Tasks

• Techniques for summarizing repositories and navigating codebases.
• Running commands and delegating specific workloads.
• Maintaining an organized task plan.

Permissions and Sandboxing

• Understanding approval and permission policies.
• Restricting file and command access for security.
• Utilizing local and remote sandbox backends.

Native Tools and Integrations

• Tools for filesystem, terminal, and shell operations.
• Support for the Model Context Protocol.
• Integration with the Language Server Protocol.

Subagents and Delegation Strategies

• Creating and forking subagents.
• Using product providers for external coding agents.
• Distributing work across an active session.

The Cordis Plugin Model

• Viewing plugins as services, events, and effects.
• Understanding shared context and lifecycle management.
• The rationale behind having no privileged core.

Profiles, Bundles, and Setup

• Layering profiles and bundles.
• Modifying configuration via cordis.patch.yml.
• Reviewing the initialized system tree.

Essential Subsystems

• The append-only nature of the session log.
• Assembly of system prompts and tool schemas.
• The mechanics of the agent loop and turn flow.

Events and Extension Capabilities

• Handling session, agent, and capability events.
• Implementing waterfall and interceptor events.
• Aligning specific behaviors with extension points.

Plugin Development

• Registering services using context keys.
• Incorporating new tools and model adapters.
• Publishing and discovering new plugins.

SDK, Headless Mode, and Automation

• Controlling the harness from external processes.
• Utilizing TypeScript and Python SDKs.
• Implementing CLI and headless automation workflows.