[Release] langchain-ai/langchain langchain-core==1.3.0a2: langchain-core==1.3.0a2

langchain-core version 1.3.0a2 is released with improvements to reference counting for garbage collection, streaming metadata optimizations, and various bug fixes. The release includes security hardening, documentation updates, and performance enhancements across multiple components including template sanitization, prompt loading, and token counting. Key fixes address symlink handling, model serialization, and tool schema validation.

Key Points

• •Implement reference counting for inherited run trees to enable proper garbage collection and memory management
• •Optimize streaming metadata handling and reduce performance overhead in core operations
• •Add comprehensive sanitization to templates and deprecated prompt save paths to prevent security vulnerabilities
• •Enhance token counting with multimodal support and approximate scaling based on reported usage metrics
• •Harden anti-SSRF protections and improve deserialization security with warnings and best practices documentation
• •Fix tool schema handling including default_factory preservation and improved error messages for non-JSON-serializable schemas
• •Add ContextOverflowError exception for better error handling in anthropic and openai integrations
• •Improve type safety and documentation across RunnableSerializable, RunnableConfig, and callback parameters
• •Support new model integrations including ChatBaseten and ChatAnthropicBedrock with proper serialization mappings
• •Reduce import time by deferring langsmith-specific imports and optimize dependency management across packages

Workflow Diagram

Concepts