<overview>
The LangChain ecosystem is split into focused, independently-versioned packages. Understanding which packages you need — and their version constraints — prevents incompatibilities and keeps upgrades predictable.
Key principles:
- LangChain 1.0 is the current LTS release. Always start new projects on 1.0+. LangChain 0.3 is legacy maintenance-only — do not use it for new work.
- langchain-core is the shared foundation: always install it explicitly alongside any other package.
- langchain-community (Python only) does NOT follow semantic versioning; pin it conservatively.
- LangGraph vs Deep Agents: choose one orchestration approach based on your use case — they are alternatives, not a required stack (see Framework Choice below).
- Provider integrations (model, vector store, tools) are installed separately so you only pull in what you use.
</overview>
Environment Requirements
<environment-requirements>
| Requirement | Python | TypeScript / Node |
|---|
| Runtime minimum | Python 3.10+ | Node.js 20+ |
| LangChain | 1.0+ (LTS) | 1.0+ (LTS) |
| LangSmith SDK | >= 0.3.0 | >= 0.3.0 |
</environment-requirements>
Framework Choice
<framework-choice>
Pick **one** agent orchestration layer. You do not need both.
| Framework | When to use | Core extra package |
|---|
| LangGraph | Need fine-grained graph control, custom workflows, loops, or branching | / |
| Deep Agents | Want batteries-included planning, memory, file context, and skills out of the box | (depends on LangGraph; installs it as a transitive dep) |
Both sit on top of
+
+
.
</framework-choice>
Core Packages
<python-packages>
Python — always required
| Package | Role | Min version |
|---|
| Agents, chains, retrieval | 1.0 |
| Base types & interfaces (peer dep) | 1.0 |
| Tracing, evaluation, datasets | 0.3.0 |
Python — orchestration (pick one)
| Package | Use when | Min version |
|---|
| Building custom graphs directly | 1.0 |
| Using the Deep Agents framework | latest |
Python — model providers (pick the one(s) you use)
| Package | Provider |
|---|
| OpenAI (GPT-4o, o3, …) |
| Anthropic (Claude) |
| Google (Gemini) |
| Mistral |
| Groq (fast inference) |
| Cohere |
| Fireworks AI |
| Together AI |
| Hugging Face Hub |
| Ollama (local models) |
| AWS Bedrock |
| Azure AI Foundry |
Python — common tool & retrieval packages
These packages have tighter compatibility requirements — use the latest available version unless you have a specific reason not to.
| Package | Adds | Notes |
|---|
| Tavily web search () | Dedicated integration package; prefer latest |
| Text chunking utilities | Semver, keep current |
| 1000+ integrations (fallback) | NOT semver — pin to minor series |
| FAISS vector store (local) | Via ; use latest |
| Chroma vector store | Dedicated integration package; prefer latest |
| Pinecone vector store | Dedicated integration package; prefer latest |
| Qdrant vector store | Dedicated integration package; prefer latest |
| Weaviate vector store | Dedicated integration package; prefer latest |
| pytest plugin for LangSmith | Requires langsmith >= 0.3.4 |
langchain-community stability note: This package is NOT on semantic versioning. Minor releases can contain breaking changes. Prefer dedicated integration packages (e.g.
,
) when they exist — they are independently versioned and more stable.
</python-packages>
<typescript-packages>
TypeScript — always required
| Package | Role | Min version |
|---|
| Base types & interfaces (peer dep) | 1.0 |
| Agents, chains, retrieval | 1.0 |
| Tracing, evaluation, datasets | 0.3.0 |
TypeScript — orchestration (pick one)
| Package | Use when | Min version |
|---|
| Building custom graphs directly | 1.0 |
| Using the Deep Agents framework | latest |
TypeScript — model providers (pick the one(s) you use)
| Package | Provider |
|---|
| OpenAI (GPT-4o, o3, …) |
| Anthropic (Claude) |
| Google (Gemini) |
| Mistral |
| Groq (fast inference) |
| Cohere |
| AWS Bedrock |
| Azure OpenAI |
| Ollama (local models) |
TypeScript — common tool & retrieval packages
| Package | Adds | Notes |
|---|
| Tavily web search () | Dedicated integration package; prefer latest |
| Broad set of community integrations | Use sparingly; prefer dedicated packages |
| Pinecone vector store | Dedicated integration package; prefer latest |
| Qdrant vector store | Dedicated integration package; prefer latest |
| Weaviate vector store | Dedicated integration package; prefer latest |
must be installed explicitly in yarn workspaces and monorepos — it is a peer dependency and will not always be hoisted automatically.
</typescript-packages>
Minimal Project Templates
<ex-langgraph-python>
<python>
Minimal dependency set for a LangGraph project (provider-agnostic).
```
# requirements.txt
langchain>=1.0,<2.0
langchain-core>=1.0,<2.0
langgraph>=1.0,<2.0
langsmith>=0.3.0
Add your model provider, e.g.:
langchain-openai
langchain-anthropic
langchain-google-genai
</python>
</ex-langgraph-python>
<ex-langgraph-typescript>
<typescript>
Minimal package.json dependencies for a LangGraph project (provider-agnostic).
```json
{
"dependencies": {
"@langchain/core": "^1.0.0",
"langchain": "^1.0.0",
"@langchain/langgraph": "^1.0.0",
"langsmith": "^0.3.0"
}
}
</typescript>
</ex-langgraph-typescript>
<ex-deepagents-python>
<python>
Minimal dependency set for a Deep Agents project (provider-agnostic).
```
# requirements.txt
deepagents # bundles langgraph internally
langchain>=1.0,<2.0
langchain-core>=1.0,<2.0
langsmith>=0.3.0
Add your model provider, e.g.:
langchain-anthropic
langchain-openai
</python>
</ex-deepagents-python>
<ex-deepagents-typescript>
<typescript>
Minimal package.json dependencies for a Deep Agents project (provider-agnostic).
```json
{
"dependencies": {
"deepagents": "latest",
"@langchain/core": "^1.0.0",
"langchain": "^1.0.0",
"langsmith": "^0.3.0"
}
}
</typescript>
</ex-deepagents-typescript>
<ex-with-tools-python>
<python>
Adding Tavily search and a vector store to a LangGraph project.
```
# requirements.txt
langchain>=1.0,<2.0
langchain-core>=1.0,<2.0
langgraph>=1.0,<2.0
langsmith>=0.3.0
Web search
langchain-tavily # use latest; partner package, semver
Vector store — pick one:
langchain-chroma # use latest; partner package, semver
langchain-pinecone # use latest; partner package, semver
langchain-qdrant # use latest; partner package, semver
Text processing
langchain-text-splitters # use latest; semver
Your model provider:
langchain-openai / langchain-anthropic / etc.
</python>
</ex-with-tools-python>
<ex-with-tools-typescript>
<typescript>
Adding Tavily search and a vector store to a LangGraph project.
```json
{
"dependencies": {
"@langchain/core": "^1.0.0",
"langchain": "^1.0.0",
"@langchain/langgraph": "^1.0.0",
"langsmith": "^0.3.0",
"@langchain/tavily": "latest",
"@langchain/pinecone": "latest"
}
}
</typescript>
</ex-with-tools-typescript>
Versioning Policy & Upgrade Strategy
<versioning-policy>
| Package group | Versioning | Safe upgrade strategy |
|---|
| , | Strict semver (1.0 LTS) | Allow minor: |
| / | Strict semver (v1 LTS) | Allow minor: |
| Strict semver | Allow minor: |
| Dedicated integration packages (e.g. , ) | Independently versioned | Allow minor updates; use latest |
| NOT semver | Pin exact minor: |
| Follow project releases | Pin to tested version in production |
Breaking changes only happen in major versions (1.x → 2.x) for all semver-compliant packages. Deprecated features remain functional across the entire 1.x series with warnings.
Prefer dedicated integration packages over langchain-community. When a dedicated package exists (e.g.
instead of
's Chroma integration), use it — dedicated packages are independently versioned and better tested.
Community tool packages (Tavily, vector stores, etc.) should be kept at latest unless your project requires a locked environment. These packages frequently release compatibility fixes alongside LangChain/LangGraph updates.
</versioning-policy>
Environment Variables
<environment-variables>
All keys are read from the environment at runtime. Set only the keys for services you actually use.
bash
# LangSmith (always recommended for observability)
LANGSMITH_API_KEY=<your-key>
LANGSMITH_PROJECT=<project-name> # optional, defaults to "default"
# Model provider — set the one(s) you use
OPENAI_API_KEY=<your-key>
ANTHROPIC_API_KEY=<your-key>
GOOGLE_API_KEY=<your-key>
MISTRAL_API_KEY=<your-key>
GROQ_API_KEY=<your-key>
COHERE_API_KEY=<your-key>
FIREWORKS_API_KEY=<your-key>
TOGETHER_API_KEY=<your-key>
HUGGINGFACEHUB_API_TOKEN=<your-key>
# Common tool/retrieval services
TAVILY_API_KEY=<your-key> # for Tavily search
PINECONE_API_KEY=<your-key> # for Pinecone
</environment-variables>
Common Mistakes
<fix-legacy-version>
Never start a new project on LangChain 0.3. It is maintenance-only until December 2026.
```
# WRONG: legacy, no new features, security patches only
langchain>=0.3,<0.4
CORRECT: LangChain 1.0 LTS
langchain>=1.0,<2.0
</fix-legacy-version>
<fix-community-unpinned>
`langchain-community` can break on minor version bumps — it does not follow semver.
WRONG: allows minor-version updates that may be breaking
langchain-community>=0.4
CORRECT: pin to exact minor series
langchain-community>=0.4.0,<0.5.0
Also consider switching to the equivalent dedicated integration package if one exists (e.g. `langchain-chroma` instead of the community Chroma integration).
</fix-community-unpinned>
<fix-community-tool-outdated>
Community tool packages like `langchain-tavily` and vector store integrations release compatibility fixes alongside LangChain updates. Using an old pinned version can cause import errors or broken tool schemas.
RISKY: old pin may be incompatible with LangChain 1.0
langchain-tavily==0.0.1
BETTER: allow latest within the current major
langchain-tavily>=0.1
</fix-community-tool-outdated>
<fix-community-import-deprecated>
Many tools that used to live in `langchain-community` now have dedicated packages with updated import paths. Always prefer the dedicated package import.
```python
# WRONG — deprecated community import path
from langchain_community.tools.tavily_search import TavilySearchResults
from langchain_community.tools import WikipediaQueryRun
from langchain_community.vectorstores import Chroma
from langchain_community.vectorstores import Pinecone
# CORRECT — use dedicated package imports
from langchain_tavily import TavilySearch # pip: langchain-tavily (TavilySearchResults is deprecated)
from langchain_community.tools import WikipediaQueryRun # no dedicated pkg yet
from langchain_chroma import Chroma # pip: langchain-chroma
from langchain_pinecone import PineconeVectorStore # pip: langchain-pinecone
To find the current canonical import for any integration, search the integrations directory:
https://python.langchain.com/docs/integrations/tools/Each entry shows the correct package and import path. If a dedicated package exists, use it — the community path may still work but is considered legacy.
</fix-community-import-deprecated>
<fix-core-not-installed>
<typescript>
`@langchain/core` is a peer dependency — it must be in your package.json, especially in monorepos.
```json
// WRONG: missing @langchain/core (breaks in yarn workspaces / strict hoisting)
{
"dependencies": {
"@langchain/langgraph": "^1.0.0"
}
}
// CORRECT: always list @langchain/core explicitly
{
"dependencies": {
"@langchain/core": "^1.0.0",
"@langchain/langgraph": "^1.0.0"
}
}
</typescript>
</fix-core-not-installed>
<fix-python-version>
<python>
Python 3.9 and below are not supported by LangChain 1.0.
```python
# Verify before installing
import sys
assert sys.version_info >= (3, 10), "Python 3.10+ required for LangChain 1.0"
</python>
</fix-python-version>
<fix-node-version>
<typescript>
Node.js below 20 is not officially supported.
```bash
# Verify before installing
node --version # must be v20.x or higher
```
</typescript>
</fix-node-version>