CoreCoder

# CoreCoder

> Formerly **NanoCoder** — renamed to avoid confusion with [Nano-Collective/nanocoder](https://github.com/Nano-Collective/nanocoder). All links from the old repo redirect here automatically.


[![PyPI](https://img.shields.io/pypi/v/corecoder)](https://pypi.org/project/corecoder/)
[![Python](https://img.shields.io/badge/python-3.10+-blue)](https://python.org)
[![License: MIT](https://img.shields.io/badge/license-MIT-green)](LICENSE)
[![Tests](https://github.com/he-yufeng/CoreCoder/actions/workflows/ci.yml/badge.svg)](https://github.com/he-yufeng/CoreCoder/actions)

[中文](README_CN.md) | [English](README.md) | [Claude Code Architecture Deep Dive (7 articles)](article/)

**512,000 lines of TypeScript → ~950 lines of Python.**

I spent two days reverse-engineering the leaked Claude Code source — all half a million lines. Then I stripped it down to the load-bearing walls and rebuilt them in Python. The result: **every key architectural pattern from Claude Code, in a codebase you can read in one sitting.**

CoreCoder is not another AI coding tool. It's a **blueprint** — the [nanoGPT](https://github.com/karpathy/nanoGPT) of coding agents. Read it, fork it, build your own.

---

```
$ corecoder -m kimi-k2.5

You > read main.py and fix the broken import

  > read_file(file_path='main.py')
  > edit_file(file_path='main.py', ...)

--- a/main.py
+++ b/main.py
@@ -1 +1 @@
-from utils import halper
+from utils import helper

Fixed: halper → helper.
```

## What You Get

Claude Code's 512K lines distilled into ~1,400 lines across 7 patterns that actually matter:

| Pattern | Claude Code | CoreCoder |
|---|---|---|
| Search-and-replace editing (unique match + diff) | FileEditTool | `tools/edit.py` — 70 lines |
| Parallel tool execution | StreamingToolExecutor (530 lines) | `agent.py` — ThreadPool |
| 3-layer context compression | HISTORY_SNIP → Microcompact → CONTEXT_COLLAPSE | `context.py` — 145 lines |
| Sub-agent with isolated context | AgentTool (1,397 lines) | `too