LangChain 1.4.0a1 introduces langchain.mcp namespace with MCPAdapter and elicitation via LangGraph interrupts

LangChain

Tools official 1 src. ~1 min

Aug 27, 2026 wave: langchain 1.4.0a1 introduces a new langchain.mcp namespace with MCPAdapter and elicitation support via LangGraph interrupts; langchain-core 1.6.1 makes StructuredTool JSON-serializable and propagates gateway information on the error path; langchain-anthropic 1.7.0 supports Anthropic SDK 1.0 and a top-level container parameter for skills plus gateway response metadata; langchain-fireworks 1.6.1 drops reasoning history blocks and refreshes model profile data; langchain 1.3.18 fixes PIIMiddleware redaction preserving content-block shape and a core indexing fix for genai v1 streaming content.

Why it matters

First MCP adapter shipped inside the LangChain package (not a separate integration); wiring elicitation through LangGraph interrupts means agents can now request clarification from inside a multi-agent graph rather than hard-coding prompts.

Importance: 3/5

notable release; official confirmation

langchain mcp adapters langgraph release v1.4.0a1 anthropic

Sources

official LangChain releases (1.4.0a1, 1.3.18, langchain-anthropic 1.7.0, langchain-core 1.6.1, langchain-fireworks 1.6.1)