claude-code-dev

name

claude-code-dev

description

How to develop, modify, and extend the Claude Code codebase following its established programming style, patterns, and conventions. Use this skill whenever working on the claude-code source — adding tools, commands, utils, components, types, hooks, services, or fixing bugs. Also use when the user asks about claude-code architecture, coding standards, file organization, or wants to understand how the codebase works. This skill ensures all contributions match the existing codebase style exactly.

Claude Code Development Style Guide

This skill captures the programming style, patterns, and conventions used in the Claude Code codebase (@anthropic-ai/claude-code). Each topic below links to a dedicated deep-dive document with comprehensive examples and rules extracted from the actual source.

Summary

Claude Code is an ESM TypeScript Node.js CLI application using Ink (React for terminals) for its UI, esbuild for transpilation, and Bun internally for feature flags and dead code elimination. Key stack: TypeScript, Zod v4, lodash-es, React/Ink, esbuild.

Detailed Guides (Resource Files)

Each topic below is covered in depth in its own resource file within this skill's directory. Read the relevant file before working on that area of the codebase.

#	Topic	File	Summary
01	Project Overview	01-project-overview.md	Tech stack, build system, runtime environment, key dependencies
02	Directory Structure	02-directory-structure.md	Full src/ layout, file organization patterns, where things go
03	Import Conventions	03-import-conventions.md	.js extensions, import type, lodash cherry-picks, feature flags, cycle breaking
04	Naming Conventions	04-naming-conventions.md	camelCase/PascalCase/UPPER_SNAKE rules, file naming, safety names
05	TypeScript Patterns	05-typescript-patterns.md	Branded types, discriminated unions, as const, satisfies, Zod schemas, generics
06	Commenting Style	06-commenting-style.md	JSDoc, why-not-what philosophy, PR references, section headers, lint suppression
07	Error Handling	07-error-handling.md	Custom error classes, utility functions, graceful degradation, catch conventions
08	Function Patterns	08-function-patterns.md	buildTool() factory, memoize, async generators, guard clauses, fire-and-forget
09	Tool Architecture	09-tool-architecture.md	Tool directory structure, buildTool() API, schemas, permissions, UI rendering
10	Command Architecture	10-command-architecture.md	Command types, index.ts pattern, lazy loading, registration
11	State Management	11-state-management.md	Module-level state, getter/setter, AppState threading, cleanup registry
12	Testing Conventions	12-testing-conventions.md	Reset helpers, NODE_ENV guards, test-only exports, deterministic sorting
13	Formatting Rules	13-formatting-rules.md	No semicolons, single quotes, trailing commas, indentation, expression style
14	Quick References	14-quick-references.md	Step-by-step checklists for adding tools, commands, utils, and types