Frameworks, Runtimes, and Harnesses
Status: ACTIVE (pulled from docs.langchain.com) Source: https://docs.langchain.com/oss/python/concepts/products Timestamp: 2026-05-11
LangChain maintains several open source packages. Understanding the differences helps choose the right tool.
| Framework | Runtime | Harness | |
|---|---|---|---|
| Value add | Abstractions, integrations | Durable execution, streaming, HITL, persistence | Predefined tools, prompts, subagents |
| When to use | Getting started quickly, standardizing team approach | Low-level control, long-running stateful workflows | Autonomous agents, complex non-deterministic tasks |
| Examples | LangChain, Vercel AI SDK, CrewAI, OpenAI Agents SDK, Google ADK | LangGraph, Temporal, Inngest | Deep Agents SDK, Claude Agent SDK, Manus |
LangChain (Framework)
Provides abstractions that make it easier to build with LLMs: structured content blocks, agent loop, middleware. Built on top of LangGraph but you don't need to know LangGraph to use LangChain.
When to use: Quick agent building, standard abstractions, straightforward applications.
LangGraph (Runtime)
Low-level orchestration framework for building, managing, and deploying long-running, stateful agents. Provides durable execution, streaming, human-in-the-loop, and persistence.
When to use: Fine-grained control, durable execution needs, complex workflows combining deterministic and agentic steps, production infrastructure.
Deep Agents SDK (Harness)
Opinionated, batteries-included framework with built-in tools on top of LangGraph: planning, task delegation, file system, token management, subagents.
When to use: Long-running agents, complex multi-step tasks, need predefined tools and prompts.
Feature Comparison
| Feature | LangChain | LangGraph | Deep Agents |
|---|---|---|---|
| Short-term memory | Yes | Yes | StateBackend |
| Long-term memory | Yes | Yes | Yes |
| Multi-agent | Subagents | Subgraphs | Subagents |
| Human-in-the-loop | Middleware | interrupt() | interrupt_on parameter |
| Streaming | Yes | Yes | Yes |
| Skills | Multi-agent skills | - | Skills |