LangChain Upgrade Migration

Current State

!npm list @langchain/core @langchain/openai 2>/dev/null | head -10

Overview

Safely upgrade LangChain versions: check compatibility, migrate import paths, convert legacy chains to LCEL, update agent APIs, and validate with tests.

Breaking Changes Timeline

0.1.x to 0.2.x (Major Restructuring)

• @langchain/core extracted as separate package
• Chat models moved to provider packages (@langchain/openai, @langchain/anthropic)
• Imports changed from langchain/* to @langchain/core/*

0.2.x to 0.3.x (LCEL Standardization)