claude-code-skill

name	claude-code-skill
description	Development conventions and architecture guide for the Claude Code CLI repository.

Claude Code — Repository Skill

Project Overview

Claude Code is Anthropic's CLI tool for interacting with Claude from the terminal. It supports file editing, shell commands, git workflows, code review, multi-agent coordination, IDE integration (VS Code, JetBrains), and Model Context Protocol (MCP).

Codebase: ~1,900 files, 512,000+ lines of TypeScript under src/.

Tech Stack

Component	Technology
Language	TypeScript (strict mode, ES modules)
Runtime	Bun (JSX support, bun:bundle feature flags)
Terminal UI	React + Ink (React for CLI)
CLI Parser	Commander.js (@commander-js/extra-typings)
API Client	@anthropic-ai/sdk
Validation	Zod v4
Linter/Formatter	Biome
Analytics	GrowthBook (feature flags & A/B testing)
Protocol	Model Context Protocol (MCP)

Architecture

Directory Map (src/)

Directory	Purpose
commands/	~50 slash commands (/commit, /review, /config, etc.)
tools/	~40 agent tools (Bash, FileRead, FileWrite, Glob, Grep, etc.)
components/	~140 Ink/React UI components for terminal rendering
services/	External integrations (API, OAuth, MCP, LSP, analytics, plugins)
bridge/	Bidirectional IDE communication layer
state/	React context + custom store (AppState)
hooks/	React hooks (permissions, keybindings, commands, settings)
types/	TypeScript type definitions
utils/	Utilities (shell, file ops, permissions, config, git)
screens/	Full-screen UIs (Doctor, REPL, Resume, Compact)
skills/	Bundled skills + skill loader system
plugins/	Plugin system (marketplace + bundled plugins)
coordinator/	Multi-agent coordination & supervisor logic
tasks/	Task management (shell tasks, agent tasks, teammates)
context/	React context providers (notifications, stats, FPS)
memdir/	Persistent memory system (CLAUDE.md, user/project memory)
entrypoints/	Initialization logic, Agent SDK, MCP entry
voice/	Voice input/output (STT, keyterms)
vim/	Vim mode keybinding support
schemas/	Zod configuration schemas
keybindings/	Keybinding configuration & resolver
migrations/	Config migrations between versions
outputStyles/	Output formatting & theming
query/	Query pipeline & processing
server/	Server/daemon mode
remote/	Remote session handling

Key Files

File	Role
src/main.tsx	CLI entry point (Commander parser, startup profiling)
src/QueryEngine.ts	Core LLM API caller (streaming, tool-call loops)
src/Tool.ts	Tool type definitions & buildTool factory
src/tools.ts	Tool registry & presets
src/commands.ts	Command registry
src/context.ts	System/user context collection (git status, memory)
src/cost-tracker.ts	Token cost tracking

Entry Points & Initialization Sequence

1. src/main.tsx — Commander CLI parser, startup profiling
2. src/entrypoints/init.ts — Config, telemetry, OAuth, MDM
3. src/entrypoints/cli.tsx — CLI session orchestration
4. src/entrypoints/mcp.ts — MCP server mode
5. src/entrypoints/sdk/ — Agent SDK (programmatic API)
6. src/replLauncher.tsx — REPL session launcher

Startup performs parallel initialization: MDM policy reads, Keychain prefetch, feature flag checks, then core init.

Patterns & Conventions

Tool Definition

Each tool lives in src/tools/{ToolName}/ and uses buildTool:

export const MyTool = buildTool({
  name: 'MyTool',
  aliases: ['my_tool'],
  description: 'What this tool does',
  inputSchema: z.object({
    param: z.string(),
  }),
  async call(args, context, canUseTool, parentMessage, onProgress) {
    // Execute and return { data: result, newMessages?: [...] }
  },
  async checkPermissions(input, context) { /* Permission checks */ },
  isConcurrencySafe(input) { /* Can run in parallel? */ },
  isReadOnly(input) { /* Non-destructive? */ },
  prompt(options) { /* System prompt injection */ },
  renderToolUseMessage(input, options) { /* UI for invocation */ },
  renderToolResultMessage(content, progressMessages, options) { /* UI for result */ },
})

Directory structure per tool: {ToolName}.ts or .tsx (main), UI.tsx (rendering), prompt.ts (system prompt), plus utility files.

Command Definition

Commands live in src/commands/ and follow three types:

• PromptCommand — Sends a formatted prompt with injected tools (most commands)
• LocalCommand — Runs in-process, returns text
• LocalJSXCommand — Runs in-process, returns React JSX

const command = {
  type: 'prompt',
  name: 'my-command',
  description: 'What this command does',
  progressMessage: 'working...',
  allowedTools: ['Bash(git *)', 'FileRead(*)'],
  source: 'builtin',
  async getPromptForCommand(args, context) {
    return [{ type: 'text', text: '...' }]
  },
} satisfies Command

Commands are registered in src/commands.ts and invoked via /command-name in the REPL.

Component Structure

• Functional React components with Ink primitives (Box, Text, useInput())
• Styled with Chalk for terminal colors
• React Compiler for optimized re-renders
• Design system primitives in src/components/design-system/

State Management

• AppState via React context + custom store (src/state/AppStateStore.ts)
• Mutable state object passed to tool contexts
• Selector functions for derived state
• Change observers in src/state/onChangeAppState.ts

Permission System

• Modes: default (prompt per operation), plan (show plan, ask once), bypassPermissions (auto-approve), auto (ML classifier)
• Rules: Wildcard patterns — Bash(git *), FileEdit(/src/*)
• Tools implement checkPermissions() returning { granted: boolean, reason?, prompt? }

Feature Flags & Build

Bun's bun:bundle feature flags enable dead-code elimination at build time:

import { feature } from 'bun:bundle'
if (feature('PROACTIVE')) { /* proactive agent tools */ }

Notable flags: PROACTIVE, KAIROS, BRIDGE_MODE, VOICE_MODE, COORDINATOR_MODE, DAEMON, WORKFLOW_SCRIPTS.

Some features are also gated via process.env.USER_TYPE === 'ant'.

Naming Conventions

Element	Convention	Example
Files	PascalCase (exports) or kebab-case (commands)	BashTool.tsx, commit-push-pr.ts
Components	PascalCase	App.tsx, PromptInput.tsx
Types	PascalCase, suffix with Props/State/Context	ToolUseContext
Hooks	use prefix	useCanUseTool, useSettings
Constants	SCREAMING_SNAKE_CASE	MAX_TOKENS, DEFAULT_TIMEOUT_MS

Import Practices

• ES modules with .js extensions (Bun convention)
• Lazy imports for circular dependency breaking: const getModule = () => require('./heavy.js')
• Conditional imports via feature flags or process.env
• biome-ignore markers for manual import ordering where needed

Services

Service	Path	Purpose
API	services/api/	Anthropic SDK client, file uploads
MCP	services/mcp/	MCP client, tool/resource discovery
OAuth	services/oauth/	OAuth 2.0 auth flow
LSP	services/lsp/	Language Server Protocol manager
Analytics	services/analytics/	GrowthBook, telemetry, events
Plugins	services/plugins/	Plugin loader, marketplace
Compact	services/compact/	Context compression
Policy Limits	services/policyLimits/	Org rate limits, quota checking
Remote Settings	services/remoteManagedSettings/	Managed settings sync (Enterprise)
Token Estimation	services/tokenEstimation.ts	Token count estimation

Configuration

Settings locations:

• Global: ~/.claude/config.json, ~/.claude/settings.json
• Project: .claude/config.json, .claude/settings.json
• System: macOS Keychain + MDM, Windows Registry + MDM
• Managed: Remote sync for Enterprise users

Guidelines

1. Read relevant source files before making changes — understand existing patterns first.
2. Follow the tool/command/component patterns above when adding new ones.
3. Keep edits minimal and focused — avoid unnecessary refactoring.
4. Use Zod for all input validation at system boundaries.
5. Gate experimental features behind bun:bundle feature flags or env checks.
6. Respect the permission system — tools that modify state must implement checkPermissions().
7. Use lazy imports when adding dependencies that could create circular references.
8. Update this file as project conventions evolve.