[Release] langchain-ai/langchain langchain==1.3.8: langchain==1.3.8

LangChain v1.3.8 release includes documentation improvements, type system enhancements, and bug fixes across the monorepo. Key updates involve replacing double backticks in docstrings for consistency, adding overloads to `create_agent`, improving async middleware decorator typing, and tightening structured output model fallbacks. The release also includes mypy version bump to 2.1 and unified type-check configuration across the project.

Key Points

• •Documentation standardization: Replaced double backticks in docstrings across core, langchain, langchain-classic, and partners packages
• •Type system improvements: Bumped mypy to 2.1 and unified type-check configuration across the monorepo for better type safety
• •Agent creation enhancements: Added overloads to `create_agent` function for improved API usability and type hints
• •Async middleware support: Fixed async middleware decorator typing to properly support asynchronous middleware patterns
• •Structured output robustness: Tightened structured output model fallbacks to improve reliability of output parsing
• •Test refactoring: Refactored `test_create_agent_tool_validation` test for better maintainability
• •Dependency management: Updated lockfiles and bumped Anthropic package to v1.4.5
• •Core library updates: Released langchain-core v1.4.6 alongside langchain v1.3.8

Workflow Diagram

Concepts