Version analyzed: March 31, 2026 leak
Total files: ~1,900 TypeScript files
Lines of code: 512,000+

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Overview

The Claude Code source is organized into a clear, modular structure with ~35 major directories. Each directory has a specific responsibility in the system.

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Root Level Files

The entry points and core orchestration files:
FilePurpose
main.tsxCLI entry point, Commander.js setup, initialization
QueryEngine.tsCore agentic loop orchestrator
query.tsAPI communication handler
Tool.tsTool type definitions and interfaces
tools.tsTool registry and initialization
commands.tsCommand registry
context.tsUser/system context gathering
cost-tracker.tsToken usage and cost tracking
history.tsCommand history management
replLauncher.tsxREPL screen launcher
setup.tsInitial setup and onboarding

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Major Directories

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/assistant - Assistant Mode (Kairos)

Feature-gated assistant mode functionality. 
assistant/
└── sessionHistory.ts    # Session history for assistant mode

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/bootstrap - Global State

Early initialization and global state management. 
bootstrap/
└── state.ts    # Global state (session ID, CWD, model config, telemetry)

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/bridge - IDE Integration

Connects Claude Code to VS Code and JetBrains IDEs. 
bridge/
├── bridgeMain.ts              # Main bridge orchestrator
├── bridgeApi.ts               # API client for bridge service
├── bridgeMessaging.ts         # Message passing
├── replBridge.ts              # REPL bridge implementation
├── sessionRunner.ts           # Session management
├── trustedDevice.ts           # Device authentication
└── types.ts                   # Bridge type definitions
Key Features:
  • Bidirectional communication with IDEs
  • Remote control capabilities
  • Session synchronization
  • OAuth authentication

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/buddy - Companion Sprite

Easter egg companion sprite feature. 
buddy/
├── companion.ts           # Companion logic
├── CompanionSprite.tsx    # React component
├── sprites.ts             # Sprite definitions
└── types.ts               # Companion types

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/cli - CLI Handlers

Non-interactive CLI mode and structured I/O. 
cli/
├── handlers/              # Command handlers for CLI mode
│   ├── agents.ts
│   ├── auth.ts
│   ├── autoMode.ts
│   └── mcp.tsx
├── transports/            # Transport layers
│   ├── SSETransport.ts
│   ├── WebSocketTransport.ts
│   └── HybridTransport.ts
└── structuredIO.ts        # JSON/NDJSON output

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/commands - Slash Commands

50+ slash command implementations. 
commands/
├── add-dir/               # /add-dir - Add working directory
├── commit.ts              # /commit - Create git commit
├── compact/               # /compact - Compress context
├── config/                # /config - Settings management
├── diff/                  # /diff - View changes
├── doctor/                # /doctor - Diagnostics
├── login/                 # /login - Authentication
├── mcp/                   # /mcp - MCP server management
├── memory/                # /memory - Memory management
├── resume/                # /resume - Resume session
├── review.ts              # /review - Code review
├── share/                 # /share - Share session
├── skills/                # /skills - Skill management
├── tasks/                 # /tasks - Task management
├── vim/                   # /vim - Vim mode toggle
└── ... (40+ more)

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/components - React UI Components

140+ Ink (React for CLI) components. 
components/
├── agents/                # Agent-related UI
├── mcp/                   # MCP server UI
├── messages/              # Message rendering
├── permissions/           # Permission dialogs
├── PromptInput/           # Input handling
├── tasks/                 # Task UI
├── teams/                 # Team/swarm UI
├── App.tsx                # Main app component
├── Message.tsx            # Message renderer
├── Messages.tsx           # Message list
├── REPL.tsx               # REPL screen (moved to screens/)
└── ... (130+ more)

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/constants - Constants & Prompts

System prompts, limits, and configuration constants. 
constants/
├── prompts.ts             # System prompt builder (CRITICAL)
├── system.ts              # System constants
├── systemPromptSections.ts # Prompt sections
├── apiLimits.ts           # API limits
├── tools.ts               # Tool constants
├── files.ts               # File type constants
├── oauth.ts               # OAuth configuration
└── xml.ts                 # XML tag constants
prompts.ts is one of the most important files - it contains the complete system prompt assembly logic.

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/context - React Contexts

React context providers for global state. 
context/
├── modalContext.tsx       # Modal management
├── notifications.tsx      # Notification system
├── stats.tsx              # Statistics tracking
└── voice.tsx              # Voice mode context

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/coordinator - Coordinator Mode

Multi-agent coordination (feature-gated). 
coordinator/
└── coordinatorMode.ts     # Coordinator implementation

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/entrypoints - Entry Points

Different entry points for different modes. 
entrypoints/
├── cli.tsx                # CLI mode entry
├── init.ts                # Initialization logic
├── mcp.ts                 # MCP server mode
├── sdk/                   # SDK entry points
└── agentSdkTypes.ts       # SDK type definitions

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/hooks - React Hooks

80+ custom React hooks. 
hooks/
├── useCanUseTool.tsx      # Permission checking
├── useIDEIntegration.tsx  # IDE connection
├── useMergedTools.ts      # Tool merging
├── useReplBridge.tsx      # Bridge management
├── useSettings.ts         # Settings access
├── useVimInput.ts         # Vim mode input
└── ... (70+ more)

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/ink - Terminal Rendering

Custom Ink renderer with optimizations. 
ink/
├── components/            # Ink components
├── events/                # Event handling
├── hooks/                 # Ink hooks
├── layout/                # Layout engine
├── termio/                # Terminal I/O
├── reconciler.ts          # React reconciler
├── renderer.ts            # Rendering engine
└── terminal.ts            # Terminal abstraction

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/keybindings - Keybinding System

Configurable keybindings. 
keybindings/
├── defaultBindings.ts     # Default keybindings
├── loadUserBindings.ts    # User customization
├── parser.ts              # Keybinding parser
├── resolver.ts            # Keybinding resolution
└── schema.ts              # Validation schema

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/memdir - Memory System

Persistent memory (MEMORY.md) management. 
memdir/
├── memdir.ts              # Core memory logic
├── paths.ts               # Memory file paths
├── findRelevantMemories.ts # Memory search
├── memoryAge.ts           # Freshness tracking
├── memoryTypes.ts         # Memory type definitions
└── teamMemPaths.ts        # Team memory (feature-gated)

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/migrations - Config Migrations

Version migrations for config changes. 
migrations/
├── migrateSonnet45ToSonnet46.ts
├── migrateOpusToOpus1m.ts
└── ... (10+ migrations)

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/plugins - Plugin System

Plugin architecture and built-in plugins. 
plugins/
├── bundled/               # Bundled plugins
└── builtinPlugins.ts      # Built-in plugin registry

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/query - Query Helpers

Query engine helper modules. 
query/
├── config.ts              # Query configuration
├── deps.ts                # Dependency injection
├── stopHooks.ts           # Stop hooks
└── tokenBudget.ts         # Token budget tracking

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/schemas - Zod Schemas

Validation schemas. 
schemas/
└── hooks.ts               # Hook schemas

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/screens - Full-Screen UIs

Full-screen React components. 
screens/
├── Doctor.tsx             # Diagnostics screen
├── REPL.tsx               # Main REPL screen
└── ResumeConversation.tsx # Resume picker

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/server - Server Mode

Direct connect server for remote sessions. 
server/
├── createDirectConnectSession.ts
├── directConnectManager.ts
└── types.ts

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/services - External Services

Integration with external services and APIs. 
services/
├── analytics/             # GrowthBook, telemetry
├── api/                   # Anthropic API client
│   ├── claude.ts          # Main API wrapper
│   ├── bootstrap.ts       # Bootstrap data
│   └── filesApi.ts        # File upload/download
├── compact/               # Context compression
├── lsp/                   # Language Server Protocol
│   └── manager.ts         # LSP server manager
├── mcp/                   # Model Context Protocol
│   ├── client.ts          # MCP client
│   ├── config.ts          # MCP configuration
│   └── types.ts           # MCP types
├── oauth/                 # OAuth authentication
├── plugins/               # Plugin management
├── policyLimits/          # Organization policies
├── remoteManagedSettings/ # Remote settings
└── tools/                 # Tool orchestration
    └── toolOrchestration.ts

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/skills - Skill System

Markdown-based workflow system. 
skills/
├── bundled/               # Bundled skills
├── bundledSkills.ts       # Bundled skill definitions
├── loadSkillsDir.ts       # Skill loader
└── mcpSkillBuilders.ts    # MCP skill builders

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/state - State Management

React state management. 
state/
├── AppState.tsx           # Main app state component
├── AppStateStore.ts       # State type definitions
├── store.ts               # Store implementation
└── selectors.ts           # State selectors

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/tasks - Task System

Background task management. 
tasks/
├── LocalAgentTask/        # Local agent tasks
├── RemoteAgentTask/       # Remote agent tasks
├── LocalShellTask/        # Shell tasks
├── DreamTask/             # Dream tasks (feature-gated)
└── types.ts               # Task type definitions

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/tools - Tool Implementations

40+ tool implementations. 
tools/
├── AgentTool/             # Sub-agent spawning
├── BashTool/              # Shell execution
├── FileReadTool/          # File reading
├── FileWriteTool/         # File creation
├── FileEditTool/          # File editing
├── GlobTool/              # File search
├── GrepTool/              # Content search
├── WebFetchTool/          # URL fetching
├── WebSearchTool/         # Web search
├── MCPTool/               # MCP tool invocation
├── LSPTool/               # LSP features
├── REPLTool/              # REPL mode
├── TaskCreateTool/        # Task creation
├── TeamCreateTool/        # Team creation
├── EnterPlanModeTool/     # Plan mode
├── EnterWorktreeTool/     # Worktree isolation
└── ... (25+ more)
Each tool directory contains:
  • {Tool}.ts - Main implementation
  • prompt.ts - Tool description and schema
  • constants.ts - Tool constants
  • Additional helper files

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/types - TypeScript Types

Shared type definitions. 
types/
├── command.ts             # Command types
├── hooks.ts               # Hook types
├── ids.ts                 # ID types (SessionId, AgentId)
├── logs.ts                # Log entry types
├── message.ts             # Message types (CRITICAL)
├── permissions.ts         # Permission types
├── plugin.ts              # Plugin types
└── generated/             # Generated types

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/utils - Utility Functions

300+ utility modules organized into subdirectories. 
utils/
├── permissions/           # Permission system
│   ├── permissions.ts
│   ├── PermissionMode.ts
│   └── permissionSetup.ts
├── settings/              # Settings management
│   ├── settings.ts
│   ├── types.ts
│   └── validation.ts
├── model/                 # Model utilities
│   ├── model.ts
│   ├── providers.ts
│   └── modelStrings.ts
├── git/                   # Git operations
├── github/                # GitHub integration
├── hooks/                 # Hook system
├── mcp/                   # MCP utilities
├── messages/              # Message utilities
├── plugins/               # Plugin utilities
├── processUserInput/      # Input processing
├── secureStorage/         # Keychain/credential storage
├── shell/                 # Shell utilities
├── skills/                # Skill utilities
├── swarm/                 # Team/swarm utilities
├── telemetry/             # Telemetry
└── ... (200+ utility files)
Key utility files:
  • api.ts - API helpers
  • auth.ts - Authentication
  • config.ts - Configuration management
  • sessionStorage.ts - Session persistence
  • queryContext.ts - Context assembly
  • thinking.ts - Thinking mode
  • tokens.ts - Token counting

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/vim - Vim Mode

Vim keybinding implementation. 
vim/
├── motions.ts             # Vim motions
├── operators.ts           # Vim operators
├── textObjects.ts         # Text objects
├── transitions.ts         # State transitions
└── types.ts               # Vim types

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/voice - Voice Mode

Voice input feature (feature-gated). 
voice/
└── voiceModeEnabled.ts    # Voice mode check

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File Naming Conventions

The codebase follows consistent naming patterns:
PatternPurposeExample
{Feature}.tsMain implementationBashTool.ts
{feature}.tsxReact componentMessage.tsx
{feature}Types.tsType definitionsagentSdkTypes.ts
{feature}Helpers.tsHelper functionsqueryHelpers.ts
use{Feature}.tsReact hookuseCanUseTool.tsx
{feature}Manager.tsManager classdirectConnectManager.ts
{feature}Config.tsConfigurationbridgeConfig.ts
constants.tsConstantstools/BashTool/constants.ts
prompt.tsTool promptstools/BashTool/prompt.ts
types.tsType definitionsbridge/types.ts
index.tsBarrel exportcommands/login/index.ts

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Import Patterns

The codebase uses several import patterns:

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Feature Gating

import { feature } from 'bun:bundle'

const module = feature('FEATURE_NAME')
  ? require('./feature.js')
  : null
Dead code elimination removes unused features at build time.

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Lazy Loading

const heavyModule = () => 
  require('./heavy.js') as typeof import('./heavy.js')
Defers loading until actually needed.

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Circular Dependency Breaking

// Lazy require to break circular dependency
const getModule = () => 
  require('./module.js').exportedFunction

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Key Files to Understand

If you want to understand Claude Code deeply, start with these files:
  1. main.tsx - Entry point, see how everything initializes
  2. QueryEngine.ts - Core agentic loop
  3. query.ts - API communication
  4. constants/prompts.ts - System prompt assembly
  5. Tool.ts - Tool interface definition
  6. tools.ts - Tool registry
  7. commands.ts - Command registry
  8. utils/sessionStorage.ts - Persistence
  9. state/AppStateStore.ts - State management
  10. services/api/claude.ts - Anthropic API wrapper

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Build Artifacts

The source compiles to: 
dist/
├── main.js                # Bundled entry point
├── main.js.map            # Source map (the leak!)
└── ... (other artifacts)
The source map pointed to a zip archive containing the full source.

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Configuration Files

User configuration lives in: 
~/.kiro/                   # User-level config
├── settings/
│   ├── settings.json      # User settings
│   └── mcp.json           # MCP servers
├── skills/                # User skills
├── plugins/               # User plugins
└── sessions/              # Session transcripts

.kiro/                     # Project-level config
├── settings/
│   ├── settings.json      # Project settings
│   └── mcp.json           # Project MCP servers
├── skills/                # Project skills
└── plugins/               # Project plugins

Architecture Overview

High-level system architecture

Control Flow

Flow from user input to output

Tools Overview

Understanding the tool system

Commands Overview

Understanding slash commands