[Release] langchain-ai/langchain langchain-core==1.4.0a1: langchain-core==1.4.0a1

langchain-core version 1.4.0a1 is an alpha release featuring the new stream_events(version='v3') protocol for improved event streaming. The release includes fixes for structured inputs preservation in tool runs, optional removal parameters in deprecation warnings, and batch size validation to prevent infinite loops. Key improvements focus on streaming capabilities, tracer metadata handling, and various bug fixes across core functionality.

Key Points

• •Introduced stream_events(version='v3') protocol for enhanced event streaming capabilities
• •Fixed preservation of structured inputs on tool runs in tracers for better data integrity
• •Made 'removal' parameter optional in warn_deprecated() function for flexibility
• •Added batch_size validation in _batch and _abatch methods to prevent infinite loops
• •Marked stream_v2/astream_v2 as beta, indicating maturation of streaming APIs
• •Implemented content-block-centric streaming (v2) for improved streaming architecture
• •Updated tracer metadata inheritance behavior for special keys
• •Enhanced SSRF (Server-Side Request Forgery) security hardening in cloud metadata
• •Added chat model and LLM invocation params to traceable metadata for better observability
• •Improved token counting with support for tool schemas in count_tokens_approximately()

Workflow Diagram

Concepts