# Langchain Stack

> Router for LangChain, LangGraph, and Deep Agents skills. Load this ONCE — it tells you which sub-skill file to read for the specific task. Use when this capability is needed.

- Skill: `tomevault-io/langchain-stack` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/langchain-stack`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/langchain-stack/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/langchain-stack

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# LangChain / LangGraph / Deep Agents — Skill Router

Do NOT load all sub-skills. Read ONLY the file(s) relevant to the current task.

## Step 1: Pick framework

If unsure which framework to use, read **framework-selection** first:
→ `~/.skills-library/langchain/framework-selection/SKILL.md` (163 lines)

## Step 2: Load the relevant sub-skill(s)

### LangChain (simple agents, tool calling)

| When | Read |
|---|---|
| Creating agents, defining tools, basic agent loop | `~/.skills-library/langchain/langchain-fundamentals/SKILL.md` (394 lines) |
| Human-in-the-loop approval, custom middleware, structured output | `~/.skills-library/langchain/langchain-middleware/SKILL.md` (388 lines) |
| RAG: document loaders, splitters, embeddings, vector stores | `~/.skills-library/langchain/langchain-rag/SKILL.md` (517 lines) |
| Package versions, installation, dependency management | `~/.skills-library/langchain/langchain-dependencies/SKILL.md` (419 lines) |

### LangGraph (stateful graphs, complex workflows)

| When | Read |
|---|---|
| StateGraph, nodes, edges, Command, Send, streaming | `~/.skills-library/langchain/langgraph-fundamentals/SKILL.md` (811 lines) |
| interrupt(), approval workflows, error handling tiers | `~/.skills-library/langchain/langgraph-human-in-the-loop/SKILL.md` (532 lines) |
| Checkpointers, thread_id, time travel, Store, subgraph persistence | `~/.skills-library/langchain/langgraph-persistence/SKILL.md` (560 lines) |

### Deep Agents (hierarchical agent systems)

| When | Read |
|---|---|
| create_deep_agent(), harness architecture, SKILL.md format | `~/.skills-library/langchain/deep-agents-core/SKILL.md` (423 lines) |
| SubAgentMiddleware, TodoList planning, HITL interrupts | `~/.skills-library/langchain/deep-agents-orchestration/SKILL.md` (471 lines) |
| StateBackend, StoreBackend, FilesystemMiddleware, CompositeBackend | `~/.skills-library/langchain/deep-agents-memory/SKILL.md` (301 lines) |

`~/.skills-library/langchain` is a symlink to the `langchain-skills` submodule — don't hardcode the submodule path, use this alias so the skill stays portable if the submodule moves.

## Rules

- Read the sub-skill file with the Read tool — it contains full API reference and examples
- For multi-concern tasks, read multiple files (e.g. langgraph-fundamentals + langgraph-persistence)
- Never guess APIs from memory — always read the file first

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> Source: [andres-ortizl/dotfiles](https://github.com/andres-ortizl/dotfiles) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-05-23 -->