# Inside Claude Code > 🔍 Inside Claude Code — Architecture Deep Dive | Flow Diagrams, UML, Sequence Diagrams | How Memory Shrinking, Tool Execution, Permissions & MCP Work Under the Hood - **Type:** MCP server - **Install:** `agentstack add mcp-luxshan2000-inside-claude-code` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [Luxshan2000](https://agentstack.voostack.com/s/luxshan2000) - **Installs:** 0 - **Category:** [AI & ML](https://agentstack.voostack.com/c/ai-and-ml) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [Luxshan2000](https://github.com/Luxshan2000) - **Source:** https://github.com/Luxshan2000/inside-claude-code ## Install ```sh agentstack add mcp-luxshan2000-inside-claude-code ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About 🔍 Inside Claude Code Architecture Deep Dive • Flow Diagrams • How Every Feature Works Under the Hood Ever wondered how Claude Code actually works? How it shrinks memory, executes tools, manages permissions, or streams responses? This repo breaks it all down — one diagram at a time. --- ## 🧠 What Is This? **Claude Code** (and its open-source sibling **Claw Code**) is an agentic AI coding assistant that lives in your terminal. It can read files, write code, run commands, search the web, and orchestrate complex multi-step tasks — all while managing context, permissions, and tool execution autonomously. **This repository is a visual architecture guide.** No code. Just diagrams, explanations, and deep dives into every subsystem that makes the magic happen. Whether you're: - 🏗️ **Building your own AI agent** and want to learn from Claude Code's architecture - 🔍 **Curious about how agentic loops work** under the hood - 📚 **Studying software architecture** patterns in production AI systems - 🛠️ **Contributing to Claw Code / Claude Code** and need to understand the internals ...this repo is for you. --- ## 🏗️ Architecture Map > **The 30,000-foot view.** How all the pieces fit together. ```mermaid graph TB subgraph "🖥️ User Interface" CLI["CLI / REPL"] SLASH["Slash Commands/compact /model /help"] end subgraph "🧠 Core Runtime" LOOP["Agentic Conversation Loop"] PROMPT["System Prompt Builder"] COMPACT["Memory Compaction"] SESSION["Session Manager"] end subgraph "🔧 Tool Ecosystem" TOOLS["Built-in Toolsbash, read, write, edit, glob, grep"] MCP["MCP Serversstdio, SSE, WebSocket"] HOOKS["Hook SystemPreToolUse / PostToolUse"] end subgraph "🔐 Security Layer" PERMS["Permission ModelReadOnly → WorkspaceWrite → DangerFull"] SANDBOX["Sandbox Execution"] AUTH["Auth: OAuth PKCE + API Keys"] end subgraph "🌐 External" API["Anthropic APIStreaming SSE"] CONFIG["Config HierarchyUser → Project → Local"] GIT["Git Integration"] end CLI --> LOOP SLASH --> LOOP LOOP --> PROMPT LOOP --> COMPACT LOOP --> SESSION LOOP --> TOOLS LOOP --> MCP TOOLS --> HOOKS TOOLS --> PERMS TOOLS --> SANDBOX LOOP --> API PROMPT --> CONFIG PROMPT --> GIT API --> AUTH ``` **[📖 Full Architecture Overview →](docs/00-architecture-overview/README.md)** --- ## 🔬 Deep Dives Each doc below zooms into **one specific feature** with flow diagrams, sequence diagrams, and detailed explanations. | # | Feature | What You'll Learn | Status | |---|---------|-------------------|--------| | 00 | [**Architecture Overview**](docs/00-architecture-overview/README.md) | High-level system design, crate structure, data flow | ✅ | | 01 | [**The Agentic Conversation Loop**](docs/01-conversation-loop/README.md) | How the core loop streams, calls tools, and iterates | ✅ | | 02 | [**Memory Shrinking & Context Compaction**](docs/02-memory-and-context/README.md) | How Claude Code fits infinite conversations into finite context | ✅ | | 03 | [**Tool System**](docs/03-tool-system/README.md) | Tool registration, execution, input schemas, built-in tools | ✅ | | 04 | [**Permission Model**](docs/04-permission-model/README.md) | Three-tier authorization, interactive prompting, escalation | ✅ | | 05 | [**MCP Integration**](docs/05-mcp-integration/README.md) | Model Context Protocol — extending tools via external servers | ✅ | | 06 | [**Hook System**](docs/06-hook-system/README.md) | Pre/Post tool hooks, exit codes, environment variables | ✅ | | 07 | [**Session Management**](docs/07-session-management/README.md) | Persistence, resume, message serialization | ✅ | | 08 | [**Streaming & SSE Parsing**](docs/08-streaming-and-sse/README.md) | Server-Sent Events, incremental parsing, real-time output | ✅ | | 09 | [**Configuration System**](docs/09-config-system/README.md) | Multi-level config, deep merge, feature extraction | ✅ | | 10 | [**Authentication**](docs/10-authentication/README.md) | OAuth PKCE flow, API keys, token refresh | ✅ | | 11 | [**CLI & REPL**](docs/11-cli-and-repl/README.md) | Terminal rendering, markdown output, input handling | ✅ | | 12 | [**Sandbox Execution**](docs/12-sandbox-execution/README.md) | Linux namespace isolation, container detection | ✅ | | 13 | [**System Prompt Building**](docs/13-system-prompt-building/README.md) | Dynamic prompt construction, CLAUDE.md discovery | ✅ | | 14 | [**Slash Commands**](docs/14-slash-commands/README.md) | Command registry, parsing, execution | ✅ | | 15 | [**Error Handling & Retry**](docs/15-error-handling-and-retry/README.md) | Error types, exponential backoff, retryability | ✅ | | 16 | [**Bootstrap Lifecycle**](docs/16-bootstrap-lifecycle/README.md) | Startup phases, initialization sequence | ✅ | --- ## 🧩 Key Concepts at a Glance ### The Conversation Loop — *The beating heart* ```mermaid graph LR A["👤 User Message"] --> B["📡 Stream to API"] B --> C{"🤖 Response Type?"} C -->|"Text"| D["💬 Display Text"] C -->|"Tool Use"| E["🔧 Execute Tool"] E --> F["🔐 Check Permission"] F --> G["⚡ Run Hook: PreToolUse"] G --> H["🏃 Execute"] H --> I["⚡ Run Hook: PostToolUse"] I --> J["📨 Send Result to API"] J --> C C -->|"End Turn"| K["✅ Done"] ``` ### Memory Compaction — *How infinite conversations fit in finite context* ```mermaid graph TD A["Token Count Check"] --> B{"Exceeds Budget?default: 200K tokens"} B -->|"No"| C["Continue Normally"] B -->|"Yes"| D["Identify Old Messages"] D --> E["Generate Summaryof Removed Turns"] E --> F["Inject Summary asSystem Context"] F --> G["Preserve Recent NMessages Intact"] G --> H["Resume withCompacted Context"] ``` ### Permission Tiers — *Security by design* ```mermaid graph LR RO["🟢 ReadOnlyread files, glob, grep"] WW["🟡 WorkspaceWrite+ write files, edit"] DA["🔴 DangerFullAccess+ bash, network, web"] RO --> WW --> DA ``` --- ## 📊 System at a Glance | Component | Details | |-----------|---------| | **Modular Architecture** | Separate modules for API, commands, runtime core, CLI, and tools | | **Built-in Tools** | 18 tools — file ops, shell, search, web, orchestration | | **MCP Transports** | 6 types — stdio, SSE, HTTP, WebSocket, SDK, proxy | | **Permission Tiers** | 3 levels — ReadOnly, WorkspaceWrite, DangerFullAccess | | **Config Sources** | 5 locations — user, project, local, CLI flags, env vars | | **Slash Commands** | 15+ — /compact, /model, /permissions, /cost, /diff, and more | | **Bootstrap Phases** | 12 ordered startup phases | | **Supported Models** | Opus, Sonnet, Haiku model families | --- ## 🗂️ Repository Structure ``` inside-claude-code/ ├── README.md ← You are here ├── LICENSE ├── assets/ │ └── banner.svg ├── docs/ │ ├── 00-architecture-overview/ ← Start here │ ├── 01-conversation-loop/ │ ├── 02-memory-and-context/ │ ├── 03-tool-system/ │ ├── 04-permission-model/ │ ├── 05-mcp-integration/ │ ├── 06-hook-system/ │ ├── 07-session-management/ │ ├── 08-streaming-and-sse/ │ ├── 09-config-system/ │ ├── 10-authentication/ │ ├── 11-cli-and-repl/ │ ├── 12-sandbox-execution/ │ ├── 13-system-prompt-building/ │ ├── 14-slash-commands/ │ ├── 15-error-handling-and-retry/ │ └── 16-bootstrap-lifecycle/ ``` --- ## 🌟 Why This Exists The agentic AI coding assistant space is **exploding**. Claude Code, Cursor, Windsurf, Copilot — they all share similar architectural patterns. Understanding how one works gives you superpowers to: 1. **Build your own** agentic coding tools 2. **Debug issues** when things go wrong 3. **Extend and customize** existing tools 4. **Learn production architecture** patterns for AI systems This repo distills thousands of lines of Rust into **clear, visual documentation** anyone can understand. --- ## 🤝 Contributing Found a mistake? Want to add a diagram? PRs welcome! 1. Fork the repo 2. Create a feature branch 3. Add or improve docs in the `docs/` folder 4. Use [Mermaid](https://mermaid.js.org/) for diagrams 5. Submit a PR --- ## 📜 License MIT — Use these docs however you like. --- ## ⭐ Star History If this helped you understand how AI coding assistants work, drop a star! [](https://star-history.com/#Luxshan2000/inside-claude-code&Date) --- Built with 🔍 curiosity and 📐 diagrams By @Luxshan2000 ## Source & license This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [Luxshan2000](https://github.com/Luxshan2000) - **Source:** [Luxshan2000/inside-claude-code](https://github.com/Luxshan2000/inside-claude-code) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** yes - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/mcp-luxshan2000-inside-claude-code - Seller: https://agentstack.voostack.com/s/luxshan2000 - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.