Deep Dive into Claude Code: A 36,000-Word Advanced Usage Guide

This 36,000-word advanced usage guide for Claude Code is not a simple translation of the official documentation. Instead, it starts from the perspectives of 'why it is designed this way' and 'how to deeply optimize', helping users build a complete mental model and master the path from 'being able to use' to 'using well'. The guide covers core content such as mental models, cost-saving tips, advanced Agent usage, and MCP integration, with 8 main chapters plus 3 appendices, suitable for developers with different needs.

As an AI programming assistant launched by Anthropic, Claude Code has helped countless developers improve coding efficiency, but most users stay at the 'being able to use' stage and do not understand the working mechanism behind the tool or the methods for deep optimization. This open-source manual was compiled by product designer Ian based on the Claude Code 2026.03 version, with a total of 36,000 words, including 8 main chapters + 3 appendices. It helps users build a complete mental model from a design perspective and master the full path from entry to proficiency.

Cost-Saving Tips

• Cost difference between fork and spawn: The fork operation constructs byte-identical API request prefixes, resulting in an extremely high prompt cache hit rate; omitting the subagent_type parameter triggers implicit fork, which can significantly reduce token consumption in multi-Agent collaboration scenarios.
• Cache mechanism: The Claude Code system prompt contains 7 static content segments, which are shared by users worldwide. This is the fundamental reason why its cost is lower than expected.

Security Mechanisms

BashTool uses four layers of security interception: the sed command only allows two specific writing methods, it has built-in 20+ command injection detectors, and covers path boundary detection for 30+ commonly used commands, achieving a balance between security and convenience.

Long Conversation Management

Claude Code's five-layer compression pipeline (from light to heavy): Tool Result Budget control, selective tool result summarization, key conversation node marking, historical conversation segment compression, and full summary for fork-specific Agents. This ensures that the core context remains complete and token consumption is reasonable even in extreme cases.

Extension System

The extension architecture for advanced users includes: custom Agent and Skill templates, Hooks automation mechanism, and Memory system persistence strategy. A Skill is a complete workflow contract that defines trigger conditions, input requirements, output specifications, and quality inspection standards.

MCP Integration

The Model Context Protocol (MCP) is an open standard promoted by Anthropic. The guide provides a complete integration process from configuration to debugging, helping users connect Claude Code to custom data sources or dedicated tools.

The guide has designed reading paths for readers with different backgrounds:

• Daily users: Start with Chapter 0 "Mental Models" to build a complete understanding before gradually learning optimization methods;
• Cost-conscious developers: Directly read Chapter 3 "Cost-Saving Guide" to master the cost difference between fork vs spawn and the three-level cache mechanism;
• Advanced users: Focus on Chapters 4,7,8 to gain complete knowledge of Agent, Skill, Hooks, and MCP integration.

The value of this manual lies not only in the disclosure of technical details but also in demonstrating the paradigm for learning complex tools—deeply understanding 'why it is designed this way'. Understanding the considerations behind Claude Code's architectural decisions (such as the AI classifier design for the permission system, cache sharing strategy, and multi-layer security protection) can help developers make more informed decisions in practice. It provides a valuable learning resource for the Chinese developer community and reflects the continuous value of the open-source spirit in the AI era.