Kode-cli/docs/develop/architecture.md

System Architecture

High-Level Architecture

┌─────────────────────────────────────────────────────────────┐
│                      User Interface Layer                    │
│  ┌─────────────┐  ┌──────────────┐  ┌──────────────────┐  │
│  │   CLI Entry │  │     REPL     │  │  React/Ink UI    │  │
│  │  (cli.tsx)  │  │  (REPL.tsx)  │  │   Components     │  │
│  └─────────────┘  └──────────────┘  └──────────────────┘  │
└─────────────────────────────────────────────────────────────┘
                              │
┌─────────────────────────────────────────────────────────────┐
│                    Command & Control Layer                   │
│  ┌─────────────┐  ┌──────────────┐  ┌──────────────────┐  │
│  │   Commands  │  │    Query     │  │     Context      │  │
│  │  (Slash /)  │  │  Engine      │  │   Management     │  │
│  └─────────────┘  └──────────────┘  └──────────────────┘  │
└─────────────────────────────────────────────────────────────┘
                              │
┌─────────────────────────────────────────────────────────────┐
│                     Tool Execution Layer                     │
│  ┌─────────────┐  ┌──────────────┐  ┌──────────────────┐  │
│  │ File Tools  │  │ System Tools │  │    AI Tools      │  │
│  │ (R/W/Edit)  │  │ (Bash/Grep)  │  │ (Task/Think)     │  │
│  └─────────────┘  └──────────────┘  └──────────────────┘  │
└─────────────────────────────────────────────────────────────┘
                              │
┌─────────────────────────────────────────────────────────────┐
│                   Service Integration Layer                  │
│  ┌─────────────┐  ┌──────────────┐  ┌──────────────────┐  │
│  │ AI Providers│  │  MCP Servers │  │  External APIs   │  │
│  │(Claude/GPT) │  │ (stdio/SSE)  │  │  (Git/Sentry)    │  │
│  └─────────────┘  └──────────────┘  └──────────────────┘  │
└─────────────────────────────────────────────────────────────┘
                              │
┌─────────────────────────────────────────────────────────────┐
│                      Infrastructure Layer                    │
│  ┌─────────────┐  ┌──────────────┐  ┌──────────────────┐  │
│  │Configuration│  │  Permissions │  │    Logging &     │  │
│  │  Management │  │    System    │  │   Error Handling │  │
│  └─────────────┘  └──────────────┘  └──────────────────┘  │
└─────────────────────────────────────────────────────────────┘

Component Relationships

Data Flow Architecture

User Input → Command Parser → Route Decision
                                    ↓
                          ┌─────────────────────┐
                          │   Slash Command?    │
                          └─────────────────────┘
                                    ↓
                    Yes ←───────────┼───────────→ No
                     ↓                              ↓
            ┌──────────────┐              ┌──────────────┐
            │Command Handler│              │ AI Query     │
            └──────────────┘              └──────────────┘
                     ↓                              ↓
            ┌──────────────┐              ┌──────────────┐
            │   Execute    │              │Tool Selection│
            └──────────────┘              └──────────────┘
                     ↓                              ↓
            ┌──────────────┐              ┌──────────────┐
            │Return Result │              │Tool Execution│
            └──────────────┘              └──────────────┘
                     ↓                              ↓
                     └──────────┬──────────────────┘
                                ↓
                        ┌──────────────┐
                        │Render Response│
                        └──────────────┘

Module Dependency Graph

cli.tsx (Entry Point)
    ├── REPL.tsx (Interactive Mode)
    │   ├── PromptInput.tsx
    │   ├── MessageResponse.tsx
    │   └── query.ts (AI Orchestration)
    │       ├── tools.ts (Tool Registry)
    │       │   ├── BashTool
    │       │   ├── FileEditTool
    │       │   ├── GrepTool
    │       │   └── [Other Tools]
    │       ├── permissions.ts
    │       └── context.ts
    ├── commands.ts (Command System)
    │   ├── Built-in Commands
    │   ├── MCP Commands
    │   └── Custom Commands
    └── services/
        ├── claude.ts
        ├── openai.ts
        ├── mcpClient.ts
        └── statsig.ts

Core Module Interactions

1. Conversation Flow

User Prompt
    ↓
Context Injection (AGENTS.md, git status, etc.)
    ↓
Model Selection (based on context size)
    ↓
API Request with Tools
    ↓
Streaming Response
    ↓
Tool Use Detection
    ↓
Permission Check
    ↓
Tool Execution
    ↓
Result Integration
    ↓
Continue or Complete

2. Tool Execution Pipeline

AI Requests Tool Use
    ↓
Tool Validation (Zod Schema)
    ↓
Permission Check
    ├── Permissive Mode → Auto-approve safe operations
    └── Safe Mode → Request user permission
    ↓
Tool Execution (Async Generator)
    ├── Yield progress updates
    ├── Handle cancellation
    └── Return results
    ↓
Format Results for AI
    ↓
Continue Conversation

3. Configuration Cascade

Environment Variables
    ↓
Global Config (~/.claude/config.json)
    ↓
Project Config (./.claude/config.json)
    ↓
Runtime Overrides (CLI flags)
    ↓
Effective Configuration

4. MCP Server Integration

MCP Server Configuration
    ↓
Server Startup (stdio/SSE)
    ↓
Tool Discovery
    ↓
Dynamic Tool Registration
    ↓
Tool Available in Conversation
    ↓
Tool Execution via MCP Protocol
    ↓
Result Translation

Key Architectural Decisions

1. Tool Abstraction

Every capability is a Tool implementing a standard interface:

interface Tool {
  name: string
  description: string
  inputSchema: ZodSchema
  needsPermissions(): boolean
  call(): AsyncGenerator<ToolCallResult>
  renderResultForAssistant(): string
}

2. Streaming Architecture

All long-running operations use async generators:

• Enables real-time progress updates
• Supports cancellation at any point
• Allows incremental result display

3. React in Terminal

Using React with Ink for terminal UI:

• Component reusability
• State management
• Complex interactive UIs
• Consistent styling

4. Permission Layers

Multi-level permission system:

• Tool Level: Each tool declares permission needs
• Session Level: Temporary permissions for current session
• Persistent Level: Saved permissions across sessions
• Mode Level: Safe vs Permissive modes

5. Context Management

Automatic context injection:

• Project files (AGENTS.md, CLAUDE.md)
• Git status and recent commits
• Directory structure
• Previous conversation history

Module Communication Patterns

Event-Driven Updates

Components communicate through:

• React props and callbacks
• Abort signals for cancellation
• Progress generators for updates
• Event emitters for cross-cutting concerns

Service Integration

External services accessed through:

• Dedicated service modules
• Unified error handling
• Retry logic with backoff
• Streaming response handling

Configuration Access

Configuration accessed via:

• Singleton config manager
• Lazy loading on first access
• Automatic migration on version change
• Validation on load

Security Architecture

Permission Model

Request → Permission Check → Decision
             ↓                    ↓
    ┌──────────────┐      ┌──────────┐
    │  Check Cache │      │   Deny    │
    └──────────────┘      └──────────┘
             ↓
    ┌──────────────┐
    │ Check Session│
    └──────────────┘
             ↓
    ┌──────────────┐
    │  Ask User    │
    └──────────────┘
             ↓
    ┌──────────────┐
    │Cache Decision│
    └──────────────┘

File System Security

• Directory-based access control
• Path traversal prevention
• Symbolic link resolution
• Hidden file protection

Command Execution Security

• Command approval system
• Environment variable sanitization
• Working directory restrictions
• Output size limits

Performance Considerations

Caching Strategy

• Model responses cached in memory
• File reads cached with freshness checks
• Configuration cached per session
• MCP tool discovery cached

Lazy Loading

• Commands loaded on first use
• MCP servers started on demand
• Context loaded incrementally
• Heavy dependencies loaded when needed

Streaming Optimizations

• Chunked response processing
• Incremental rendering
• Partial result display
• Early termination support

Extension Points

Adding New Tools

1. Create class extending Tool
2. Implement required methods
3. Register in tools.ts
4. Tool automatically available

Adding AI Providers

1. Implement provider interface
2. Add to ModelManager
3. Configure in model profiles
4. Provider available for use

Adding Commands

1. Create command handler
2. Register in commands.ts
3. Command available via slash

Adding MCP Servers

1. Configure server details
2. Server tools auto-discovered
3. Tools available in conversation

System Boundaries

Internal Boundaries

• Clear module interfaces
• Dependency injection
• Service abstractions
• Tool isolation

External Boundaries

• API rate limiting
• File system access control
• Network request timeouts
• Resource consumption limits

Scalability Considerations

Horizontal Scalability

• Stateless command execution
• Independent tool operations
• Parallel tool execution (when safe)
• Distributed MCP servers

Vertical Scalability

• Streaming for large responses
• Chunked file processing
• Incremental context loading
• Memory-efficient caching

This architecture provides a robust, extensible foundation for an AI-powered development assistant while maintaining security, performance, and user experience as primary concerns.