ICYMI -- yesterday we released support for the new MCP protocol in @LangChain !! what do you need to know?
1. MCP support is now in the main langchain package! get started with `uv pip install 'langchain[mcp]'`
2. it's now built on top of FastMCP v4; FastMCP has ergonomic
we're adding support for the new MCP spec in @LangChain open source!
the new API is built on top of FastMCP, so you can take advantage of their excellent devx for building MCP servers and clients.
an early version is available in langchain==1.4.0a2; let us know what you think!
What's new in LangChain? 🚀
🧯 Standard exceptions: chat models now raise standard exception types across providers, so you can distinguish retryable errors (timeouts, rate limits, etc.) in a consistent way. Fully backward compatible.
🧩 Agent middleware: custom token_counter
What's new in LangChain? 🚀
🔌 Support for OpenAI's 3.0 SDK (using httpx2)
✨ Support for gemini-3.7-flash
Plus a wave of core reliability fixes from external contributors:
🛠️ Tool calling & structured output: clearer errors, respect for pydantic aliases when validating tool
