# langgraph

A Claude skill for building LangGraph agents: state, branching, checkpointers and the ReAct loop.

- skill · `type=skill` · Claude Code · 257 installs
- Author: davila7
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/skills/ai-research/langgraph
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/skills/langgraph

## What it does

This skill turns Claude into a LangGraph architect. It walks through `StateGraph` construction: declaring state, adding nodes and edges, wiring conditional routing. Reducers get their own treatment — `add_messages` appends instead of overwriting, and a custom reducer can merge dicts coming from several nodes.

Inside are code templates: a basic ReAct agent with `ToolNode`, state with multiple reducers, branching on query type. There is also an anti-patterns section. A loop with no exit burns tokens, and stateless nodes throw away the main LangGraph benefit — you cannot resume a conversation.

You need Python 3.9+, the `langgraph` package and LLM API access such as OpenAI or Anthropic. If your graph has a cycle, put an iteration counter in state: without an exit condition the agent loops and hits your request limit.

## Requirements
- Works with: LinkedIn

## Install

### Claude Code (native platform)

1. **claude-code-templates**
```bash
npx claude-code-templates@latest --skill ai-research/langgraph
```

2. **Skills CLI (Vercel)**
```bash
npx skills add davila7/claude-code-templates --skill langgraph -a claude-code
```

3. **Manually: put the files in place**
- File: `~/.claude/skills/langgraph/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/langgraph/

### Codex

**Manually: put the files in place**
- File: `.agents/skills/langgraph/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

**Manually: put the files in place**
- File: `.cursor/skills/langgraph/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install davila7/claude-code-templates langgraph
```

2. **Manually: put the files in place**
- File: `.github/skills/langgraph/SKILL.md`

### Gemini CLI

**Platform CLI**
```bash
gemini skills install https://github.com/davila7/claude-code-templates --path cli-tool/components/skills/ai-research/langgraph
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/langgraph/SKILL.md` — The legacy .windsurf/skills/ path still works

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/davila7/claude-code-templates/tree/HEAD/cli-tool/components/skills/ai-research/langgraph

## When to use it
- build a ReAct agent that calls tools
- define state with reducers for accumulating data
- route queries into branches with conditional edges
- add a checkpointer and resume a conversation
- catch an infinite loop in an agent graph

## Example prompts
- help me build a StateGraph for an agent with search and a calculator
- write state with a reducer that merges findings from several nodes
- add an exit condition based on an iteration counter

## Similar
- [langgraph-persistence](https://affpapa.org/en/nevibecode/skills/langgraph-persistence.md) — skill · 18000 installs
- [langgraph-python-quickstart](https://affpapa.org/en/nevibecode/skills/langgraph-python-quickstart.md) — skill · 5200 installs
- [options-analytics-agent-langgraph](https://affpapa.org/en/nevibecode/skills/options-analytics-agent-langgraph.md) — skill · 2000 installs
- [langgraph-code-review](https://affpapa.org/en/nevibecode/skills/langgraph-code-review.md) — skill · 884 installs
- [langchain-development](https://affpapa.org/en/nevibecode/skills/langchain-development.md) — skill · 681 installs
- [migrating-langchain-to-pydantic-ai](https://affpapa.org/en/nevibecode/skills/migrating-langchain-to-pydantic-ai.md) — skill · 314 installs

## Other versions with the same name
- [langgraph · sickn33](https://affpapa.org/en/nevibecode/skills/sickn33-langgraph.md) — 1300 installs
- [langgraph · yonatangross](https://affpapa.org/en/nevibecode/skills/orchestkit-langgraph.md) — 359 installs

From the same set: [davila7/claude-code-templates](https://affpapa.org/en/nevibecode/by/davila7/claude-code-templates.md) — 224 cards

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md