> ## Documentation Index
> Fetch the complete documentation index at: https://labs.prompthon.io/llms.txt
> Use this file to discover all available pages before exploring further.

# LangGraph Starter

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## Summary

This starter shows the smallest useful graph-shaped agent example in the repo:
plan, route, synthesize.

## Status

`starter`

Source code: [ecosystem/examples/langgraph-starter](https://github.com/Prompthon-IO/agent-systems-handbook/tree/main/ecosystem/examples/langgraph-starter)

## Why It Exists

Framework comparison pages are easier to extend when contributors can point to
small repo-owned examples instead of only to external demos. This starter keeps
the shape recognizable without turning the repo into a framework tutorial set.

## Related Lab Pages

* [Agent Frameworks](/ecosystem/agent-frameworks)
* [Ecosystem Overview](/ecosystem)

## Folder Structure

```text theme={null}
langgraph-starter/
├── index.mdx
└── src/
    ├── branching.py
    ├── graph.py
    └── run_summary.py
```

## Quick Start

This project is a starter. Read `src/graph.py` for the minimal graph state and
node boundaries, then expand it into a fuller runnable example if needed. For a
repo-level smoke check, run `python3 scripts/verify_example_projects.py` from
the repository root.

## Included Sample Files

* `src/graph.py`: a minimal plan, route, synthesize state transition sketch
* `src/branching.py`: a narrow example of how route choice and retry policy can
  be made explicit
* `src/run_summary.py`: a tiny reporting surface for turning graph state into a
  readable execution summary

## Constraints

* No framework dependency is wired.
* The graph is illustrative rather than executable.
* Tool adapters and model calls are placeholders.

## Next Steps

* Add a real runtime dependency.
* Add one tool node and one retry path.