Architecture

# The Four-Layer Engine

Pneuma is built on four distinct layers, cleanly separating the concerns of AI execution, visual rendering, and domain-specific knowledge.

4

### Mode Protocol

ModeManifest

The declarative soul. Defines what the AI knows (skills), what the user sees (viewers), and how the agent is configured.

3

### Content Viewer

ViewerContract

The dynamic frontend. Renders workspace files in real-time, extracts context, and provides agent-callable actions.

2

### Agent Bridge

AgentBackend

The AI orchestrator. Handles launching, resuming, and communicating with the underlying CLI agents (e.g. Claude Code).

1

### Runtime Shell

Bun + Hono + Vite

The foundation. Manages file watching, PTY terminals, session persistence, and hosts the Dual WebSocket bridge.