agent-builder

We created this repository out of admiration for Claude Code - what we believe to be the most capable AI coding agent in the world. Initially, we attempted to reverse-engineer its design through behavioral observation and speculation. The analysis we published was riddled with inaccuracies, unfounded guesses, and technical errors. We deeply apologize to the Claude Code team and anyone who was misled by that content.

Over the past six months, through building and iterating on real agent systems, our understanding of "what makes a true AI agent" has been fundamentally reshaped. We'd like to share these insights with you. All previous speculative content has been removed and replaced with original educational material.

---

> Works with [Kode CLI](https://github.com/shareAI-lab/Kode), Claude Code, Cursor, and any agent supporting the [Agent Skills Spec](https://github.com/anthropics/agent-skills).

After completing this tutorial, you will understand:

• The Agent Loop - The surprisingly simple pattern behind all AI coding agents
• Tool Design - How to give AI models the ability to interact with the real world
• Explicit Planning - Using constraints to make AI behavior predictable
• Context Management - Keeping agent memory clean through subagent isolation
• Knowledge Injection - Loading domain expertise on-demand without retraining

```

Start Here

|

v

[v0: Bash Agent] -----> "One tool is enough"

| 16-50 lines

v

[v1: Basic Agent] ----> "The complete agent pattern"

| 4 tools, ~200 lines

v

[v2: Todo Agent] -----> "Make plans explicit"

| +TodoManager, ~300 lines

v

[v3: Subagent] -------> "Divide and conquer"

| +Task tool, ~450 lines

v

[v4: Skills Agent] ---> "Domain expertise on-demand"

+Skill tool, ~550 lines

```

Recommended approach:

1. Read and run v0 first - understand the core loop
2. Compare v0 and v1 - see how tools evolve
3. Study v2 for planning patterns
4. Explore v3 for complex task decomposition
5. Master v4 for building extensible agents

```bash

# Clone the repository

git clone https://github.com/shareAI-lab/learn-claude-code

cd learn-claude-code

# Install dependencies

pip install -r requirements.txt

# Configure API key

cp .env.example .env

# Edit .env with your ANTHROPIC_API_KEY

# Run any version

python v0_bash_agent.py # Minimal (start here!)

python v1_basic_agent.py # Core agent loop

python v2_todo_agent.py # + Todo planning

python v3_subagent.py # + Subagents

python v4_skills_agent.py # + Skills

```

Every coding agent is just this loop:

```python

while True:

response = model(messages, tools)

if response.stop_reason != "tool_use":

return response.text

results = execute(response.tool_calls)

messages.append(results)

```

That's it. The model calls tools until done. Everything else is refinement.

| Ver