Appendix A Source Map: Which Files This Comparison Primarily Relies On

This appendix does one thing only: it states which files each chapter's judgments mainly rely on. It is not a directory of reproduced source, nor does it imply that the book ships source code together with its arguments.

The same boundary applies here:

• only the minimum engineering citation and module location is used
• the body of Claude Code or Codex implementation is not reproduced
• no long source transcription is provided

A.1 Primary references on the Claude Code side

Overall control plane and prompt:

• src/constants/prompts.ts
• src/utils/systemPrompt.ts
• src/utils/claudemd.ts
• src/memdir/memdir.ts

Runtime loop and recovery:

• src/query.ts
• src/QueryEngine.ts
• src/services/compact/autoCompact.ts
• src/services/compact/compact.ts

Tools and permissions:

• src/services/tools/toolOrchestration.ts
• src/services/tools/toolExecution.ts
• src/services/tools/StreamingToolExecutor.ts
• src/hooks/useCanUseTool.tsx
• src/tools/BashTool/prompt.ts
• src/tools/BashTool/bashPermissions.ts

Multi-agent work, skills, and hooks:

• src/utils/forkedAgent.ts
• src/coordinator/coordinatorMode.ts
• src/tasks/LocalAgentTask/LocalAgentTask.tsx
• src/tools/SkillTool/SkillTool.ts
• src/tools/SkillTool/prompt.ts
• src/utils/hooks/hooksConfigManager.ts

A.2 Primary references on the Codex side

Core module skeleton:

• core/src/lib.rs
• tools/src/lib.rs
• skills/src/lib.rs
• hooks/src/lib.rs

Instruction fragments and user injection:

• instructions/src/lib.rs
• instructions/src/fragment.rs
• instructions/src/user_instructions.rs
• docs/agents_md.md

Tools, approvals, and execution policy:

• tools/src/local_tool.rs
• tools/src/agent_tool.rs
• execpolicy/src/lib.rs
• docs/execpolicy.md
• docs/sandbox.md

Threads and state:

• sdk/typescript/src/thread.ts
• core/src/lib.rs
• core/src/thread_manager.rs
• core/src/rollout.rs
• core/src/state_db_bridge.rs
• core/src/message_history.rs

Hook event engine:

• hooks/src/engine/mod.rs

A.3 Chapter-to-file mapping

Chapter 1:

• Claude Code's query.ts, toolOrchestration.ts
• Codex's core/src/lib.rs

Chapter 2:

• Claude Code's prompt assembly and CLAUDE.md
• Codex's fragment.rs, user_instructions.rs

Chapter 3:

• Claude Code's query loop and QueryEngine
• Codex's thread.ts, plus exposed modules around thread_manager, rollout, and state_db_bridge

Chapter 4:

• Claude Code's tool orchestration, Bash restrictions, and permission semantics
• Codex's tools/src/lib.rs, local_tool.rs, and execpolicy/src/lib.rs

Chapter 5:

• Claude Code's skill, hook, and memory system
• Codex's skills system and hook engine

Chapter 6:

• Claude Code's forked-agent design and verification discipline
• Codex's agent-tool set and its thread / rollout / state structures

Chapter 7:

• the cumulative judgment produced by the whole file set above