langchain langchain==1.4.0a3

Third alpha of the line. This release focuses on the new namespace for adapting MCP servers into LangChain tools. ## highlights - **** adapts any target accepts — a URL, a local script, an in-process server, an naming several servers, or a pre-built client — as well as a FastMCP for a fleet of servers behind one client. - **** discovers and adapts tools, with optional client-side response caching (SEP-2549): serves a cached list within the server's TTL hint, repopulates it, skips it. - **** converts a single MCP tool for callers managing their own client. - **Tool metadata** is grouped under an namespace on each tool: the tool's (snake_case) and under , and the serving server's identity under . - **** surfaces a server's mid-call questions as LangGraph interrupts, so a human answers and the run resumes. Requires the extra: (and ). ## Install This is a pre-release; install…