Inside Claude Code

20-page deep dive into Anthropic's AI coding agent — from source code. 1,902 files, 513K lines of TypeScript. Click any page to dive in.

Overview & Stack

Bun runtime, Ink UI, Zustand state, 4 providers, 6 MCP transports, directory map

Architecture & Boot

System flow, core loop, rendering pipeline, state layers, boot sequence, src/ folder structure, feature gates

Async generator, 6-step flow, continuation decisions, post-sampling hooks

43 tools, streaming executor, sibling abort, fork cache sharing

3-layer model, 7 modes, 8 rule sources, bash AST analysis

Context & Autocompact

167K threshold, hybrid token counting, 4 strategies, circuit breaker

API & Providers

Why 4 providers, feature matrix, retry strategy, fast mode states

Subagents & Swarm

7-step lifecycle, fork mechanics, 6 agent types, team topology, backends

MEMORY.md as pointer index, Sonnet selection, 4 types, autoDream

6-layer defense, 24 bash validators, ML classifier, never-bypassable

Priority order, MCP/Skills/Agents/Hooks/Plugins/CLAUDE.md

CLI & Hidden Internals

84 commands, 24+ internal, 170+ env vars, 26 feature flags

Architecture Critique

God object, SOLID scorecard, 4,684-line main.tsx, 187 imports

Speculation System

Overlay filesystem, pre-computed turns, pipelined speculation, state machine

Buddy Companion

18 species, rarity tiers, stats, hats, shiny 1%, procedural generation

Computer Use & Voice

Chicago MCP (Rust/Swift), voice mode (SoX → STT), kill-switches

3-layer pipeline, PII never-type trick, GrowthBook, Datadog

Team Memory Sync

Delta upload, SHA-256 hashing, secret scanning, conflict resolution

Coordinator & Deep Links

Worker orchestration, scratchpads, claude-cli:// URIs

Easter Eggs & Evolution

200+ spinner verbs, codenames, model migrations, Chrome integration