langchain-rag

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha a78b2e2257e3 · 29 Oct 2026Report an issue or request a re-scan

• Publisherlangchain-ai GitHub organizationOwner of the repository this skill is read from
• Source folderlangchain-ai/langchain-skills/config/skills/langchain-ragThe exact folder we audited
• LicenceMITAs the repository states it
• Commit pinned for this verdicta78b2e2257e3A new audit runs when the source changes
• Repository statusNot archivedLast push 3 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: INVOKE THIS SKILL when building ANY retrieval-augmented generation (RAG) system. Covers document loaders, RecursiveCharacterTextSplitter, embeddings (OpenAI), and vector stores (Chroma, FAISS, Pinecone).

---
name: langchain-rag
description: "INVOKE THIS SKILL when building ANY retrieval-augmented generation (RAG) system. Covers document loaders, RecursiveCharacterTextSplitter, embeddings (OpenAI), and vector stores (Chroma, FAISS, Pinecone)."
---

<overview>
Retrieval Augmented Generation (RAG) enhances LLM responses by fetching relevant context from external knowledge sources.

**Pipeline:**
1. **Index**: Load → Split → Embed → Store
2. **Retrieve**: Query → Embed → Search → Return docs
3. **Generate**: Docs + Query → LLM → Response

**Key Components:**
- **Document Loaders**: Ingest data from files, web, databases
- **Text Splitters**: Break documents into chunks
- **Embeddings**: Convert text to vectors
- **Vector Stores**: Store and search embeddings
</overview>

<vectorstore-selection>

| Vector Store | Use Case | Persistence |
|--------------|----------|-------------|
| **InMemory** | Testing | Memory only |
| **FAISS** | Local, high performance | Disk |
| **Chroma** | Development | Disk |
| **Pinecone** | Production, managed | Cloud |

</vectorstore-selection>

---

## Complete RAG Pipeline

<ex-basic-rag-setup>
<python>
End-to-end RAG pipeline: load documents, split into chunks, embed, store, retrieve, and generate a response.

```python
from langchain_openai import ChatOpenAI, OpenAIEmbeddings
from langchain_community.vectorstores import InMemoryVectorStore
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_core.documents import Document

# 1. Load documents
docs = [
    Document(page_content="LangChain is a framework for LLM apps.", metadata={}),
    Document(page_content="RAG = Retrieval Augmented Generation.", metadata={}),
]

# 2. Split documents
splitter = RecursiveCharacterTextSplitter(chunk_size=500, chunk_overlap=50)
splits = splitter.split_documents(docs)

# 3. Create embeddings and store
embeddings = OpenAIEmbeddings(model="text-embedding-3-small")
vectorstore = InMemoryVectorStore.from_documents(splits, embeddings)

# 4. Create retriever
retriever = vectorstore.as_retriever(search_kwargs={"k": 4})

# 5. Use in RAG
model = ChatOpenAI(model="gpt-4.1")
query = "What is RAG?"
relevant_docs = retriever.invoke(query)

context = "\n\n".join([doc.page_content for doc in relevant_docs])
response = model.invoke([
    {"role": "system", "content": f"Use this context:\n\n{context}"},
    {"role": "user", "content": query},
])
```
</python>
<typescript>
End-to-end RAG pipeline: load documents, split into chunks, embed, store, retrieve, and generate a response.

```typescript
import { ChatOpenAI, OpenAIEmbeddings } from "@langchain/openai";
import { MemoryVectorStore } from "@langchain/classic/vectorstores/memory";
import { RecursiveCharacterTextSplitter } from "@langchain/textsplitters";
import { Document } from "@langchain/core/documents";

// 1. Load documents
const docs = [
  new Document({ pageContent: "LangChain is a framework for LLM apps.", metadata: {} }),
  new Document({ pageContent: "RAG = Retrieval Augmented Generation.", metadata: {} }),
];

// 2. Split documents
const splitter = new RecursiveCharacterTextSplitter({ chunkSize: 500, chunkOverlap: 50 });
const splits = await splitter.splitDocuments(docs);

// 3. Create embeddings and store
const embeddings = new OpenAIEmbeddings({ model: "text-embedding-3-small" });
const vectorstore = await MemoryVectorStore.fromDocuments(splits, embeddings);

// 4. Create retriever
const retriever = vectorstore.asRetriever({ k: 4 });

// 5. Use in RAG
const model = new ChatOpenAI({ model: "gpt-4.1" });
const query = "What is RAG?";
const relevantDocs = await retriever.invoke(query);

const context = relevantDocs.map(doc => doc.pageContent).join("\n\n");
const response = await model.invoke([
  { role: "system", content: `Use this context:\n\n${context}` },
  { role: "user", content: query },
]);
```
</typescript>
</ex-basic-rag-setup>

---

## Document Loaders

<ex-loading-pdf>
<python>
Load a PDF file and extract each page as a separate document.

```python
from langchain_community.document_loaders import PyPDFLoader

loader = PyPDFLoader("./document.pdf")
docs = loader.load()
print(f"Loaded {len(docs)} pages")
```
</python>
<typescript>
Load a PDF file and extract each page as a separate document.

```typescript
import { PDFLoader } from "@langchain/community/document_loaders/fs/pdf";

const loader = new PDFLoader("./document.pdf");
const docs = await loader.load();
console.log(`Loaded ${docs.length} pages`);
```
</typescript>
</ex-loading-pdf>

<ex-loading-web-pages>
<python>
Fetch and parse content from a web URL into a document.

```python
from langchain_community.document_loaders import WebBaseLoader

loader = WebBaseLoader("https://docs.langchain.com")
docs = loader.load()
```
</python>
<typescript>
Fetch and parse content from a web URL into a document using Cheerio.

```typescript
import { CheerioWebBaseLoader } from "@langchain/community/document_loaders/web/cheerio";

const loader = new CheerioWebBaseLoader("https://docs.langchain.com");
const docs = await loader.load();
```
</typescript>
</ex-loading-web-pages>

<ex-loading-directory>
<python>
Load all text files from a directory using a glob pattern.

```python
from langchain_community.document_loaders import DirectoryLoader, TextLoader

# Load all text files from directory
loader = DirectoryLoader(
    "path/to/documents",
    glob="**/*.txt",  # Pattern for files to load
    loader_cls=TextLoader
)
docs = loader.load()
```
</python>
</ex-loading-directory>

---

## Text Splitting

<ex-text-splitting>
<python>
Split documents into chunks using RecursiveCharacterTextSplitter with configurable size and overlap.

```python
from langchain_text_splitters import RecursiveCharacterTextSplitter

splitter = RecursiveCharacterTextSplitter(
    chunk_size=1000,        # Characters per chunk
    chunk_overlap=200,      # Overlap for context continuity
    separators=["\n\n", "\n", " ", ""],  # Split hierarchy
)

splits = splitter.split_documents(docs)

Excerpt, first 6,000 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/langchain-ai/langchain-skills
git -C langchain-skills checkout a78b2e2257e3

Works in

1. 2026-10-29
   ✓SAFE B 89 / 100

   first audit · source a78b2e2257e3

Questions about langchain-rag

• github.com/langchain-ai/langchain-skills/tree/main/config/skills — the audited source at commit a78b2e2257e3 and every finding aboveObserved · 29 Oct 2026

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