🔬 Agentic Apps Internals

How AI coding agents actually work under the hood
System prompts, tool architectures, session traces, and implementation patterns — captured from real agent sessions.

by AgenticLoops.ai - for Engineers, from Engineers

🔍 What's Inside

This repository contains captured API traffic, decoded system prompts, complete tool schemas, and turn-by-turn session traces from real AI coding agent sessions. Everything here comes from actual intercepted data — no guesswork, no assumptions.

For each agent you'll find:

• System Prompts — the exact instructions that shape agent behavior, extracted from live API traffic
• Tool Catalogs — complete tool definitions with full JSON schemas, descriptions, and categories
• Session Traces — turn-by-turn breakdowns showing every LLM call, tool use, and token count
• Prompt Engineering Analysis — how each agent structures its prompts, what sections they include, and how prompts change between modes

Interesting things you'll discover:

📖 The exact system prompt that tells Claude Code to "avoid over-engineering" — and the detailed rules that follow it
⚖️ 5 tools vs 65 tools — same task, radically different approaches — Codex CLI's minimalism vs Copilot's comprehensive toolset
🧠 Codex CLI's explicit engineering values: "Clarity, Pragmatism, Rigor" — personality encoded directly in the system prompt

Useful for:

• AI Engineers building coding assistants or agent systems
• Researchers studying LLM agent architectures and prompt design
• Developers learning advanced prompt engineering from production systems
• Anyone curious about what happens behind /ask, /agent, or /plan

---

🗺️ Start Here

New to the repo? Follow this reading path:

1. Pick an agent — Choose Claude Code, Codex CLI, Copilot, or OpenCode and read its README
2. System Prompt — Read the agent's system-prompt.md to see the exact instructions it receives
3. Prompt Engineering — Read PROMPT-ENGINEERING.md for how the prompt is structured and how it changes between modes
4. Tool Catalog — Browse TOOL-USE.md for the full tool definitions with JSON schemas
5. Session Traces — Check session.md for turn-by-turn breakdowns of real agent sessions

---

🤖 Agents Analyzed