Architecture & Module Map

Layered Architecture

Claude Code uses a clear layered architecture, forming a complete data pipeline from user input to LLM interaction:

Directory/File	Files	Responsibility
`entrypoints/`	8	Process entry: `cli.tsx` (CLI bootstrap), `init.ts` (one-time init), `mcp.ts` (MCP server mode), SDK types
`main.tsx`	1	Commander CLI setup, GrowthBook init, tool registration, REPL launch
`bootstrap/`	1	`state.ts`: global bootstrap state (telemetry, channels, settings cache)

File	Responsibility
`query.ts`	Core agent loop: `query()` / `queryLoop()` state machine driving LLM calls -> tool execution -> result injection
`QueryEngine.ts`	SDK / headless mode wrapper managing per-session message lists, abort, file cache
`Tool.ts`	Tool interface definitions: `Tool<Input, Output>`, `ToolUseContext`, `ToolPermissionContext`, `buildTool()`
`tools.ts`	Tool registry: `getAllBaseTools()` returns all built-in tools, `getTools()` filters by permissions
`commands.ts`	Command registry: merges bundled/plugin/skill/built-in commands, sorted by priority

Subdirectory	Responsibility
`api/`	Anthropic API client construction, streaming calls, retries, file API
`mcp/`	MCP client connection management, tool discovery, config merging
`compact/`	Context compaction (full/micro/auto)
`analytics/`	GrowthBook feature flags, analytics events
`oauth/`	OAuth 2.0 authentication flow
`tools/`	Tool orchestration (`toolOrchestration.ts`), execution (`toolExecution.ts`), streaming executor
`lsp/`	Language Server Protocol integration
`policyLimits/`	Organization policy limits
`remoteManagedSettings/`	Remote managed settings (enterprise)
`SessionMemory/`	Session memory extraction
`teamMemorySync/`	Team memory synchronization

Directory	Files	Responsibility
`ink/`	96	Custom Ink rendering engine: React reconciler + Yoga layout + terminal cell buffer
`screens/`	3	Full-screen UIs: `REPL.tsx` (main interaction), `Doctor.tsx` (diagnostics), `ResumeConversation.tsx`
`components/`	389	Ink UI components: message display, permission dialogs, input, design system, task panels, etc.
`hooks/`	104	React hooks: tool permissions, notifications, settings changes, etc.
`keybindings/`	14	Keybinding definitions and handling (chord support)
`vim/`	5	Vim mode implementation (motions, operators, text objects)

Subdirectory	Responsibility
`permissions/`	Core permission decision logic, rule parsing, setup
`settings/`	Layered config loading and merging (user/project/local/flag/policy)
`model/`	Model selection, provider branching, capability checks
`swarm/`	Multi-agent coordination: in-process teammates, tmux/iTerm backends
`bash/`	Bash command parsing and security classification
`plugins/`	Plugin loader
`hooks/`	Lifecycle hooks
`telemetry/`	Telemetry reporting

Directory	Files	Responsibility
`plugins/`	2	Plugin system (built-in plugin registration)
`skills/`	20	Skill system (bundled skills, disk skill loading)
`bridge/`	31	IDE bridge (VS Code, JetBrains)
`tasks/`	12	Task framework: local/remote agent tasks, teammate tasks

A complete user interaction flows through:

Go to 02-startup-flow.md to understand the complete startup process from command line to interactive loop.