Architecture

How Cortex Works

Cortex is a VS Code extension that integrates OpenCode as the agentic runtime (local server). Cortex adds the IDE layer — chat sidebar, local codebase context, and Cursor/Windsurf-like workflows — inside your own editor. Models come from your OpenCode subscription.

┌──────────────┐     ┌──────────────┐     ┌──────────────┐
│  VS Code UI  │ ←→  │ Cortex Ext.  │ ←→  │  OpenCode    │
│  (Sidebar +  │     │ (TypeScript) │     │  (Server)    │
│   Inline)    │     │              │     │              │
└──────────────┘     └──────────────┘     └──────┬───────┘
                                                  │
                                          ┌───────▼───────┐
                                          │ OpenCode      │
                                          │ models        │
                                          │ (your sub)    │
                                          └───────────────┘

Components

• SidebarProvider — manages the chat panel lifecycle, message routing, and plan/build modes
• OpenCode Client — HTTP client that talks to the local OpenCode server
• Context Service — gathers relevant code context via lexical + embedding search
• Inline Completion — provides ghost-text suggestions in the editor
• Plan Store — manages saved plans with checklists for the Plan→Build workflow

Plan → Build Workflow

1. Plan mode: Cortex analyzes your request and creates a structured plan with checklist
2. Approval: You review and approve the plan
3. Build mode: Cortex implements changes step by step, updating the checklist