# 02 Session Lineage

Script: `example/02_session_lineage.py`.

This key-free script shows `fork()`, `detach()`, manual session registration, graph traversal, and JSONL lineage export.

```bash
python example/02_session_lineage.py
```

| Concept | API |
| --- | --- |
| Branch session state | `session.fork()` |
| Start a fresh lineage root | `session.detach()` |
| Traverse graph | `ancestors_bfs(...)`, `edge_pairs(...)` |
| Export graph | `export_journal_jsonl(...)` |

The script writes `lineage_demo.jsonl` in the current directory so you can inspect the emitted session rows.

[← Runnable Examples](index.md)