As a LangChain user streaming a tool-calling model, I expect each streamed chunk to expose structured `tool_call_chunk` content blocks so I can render or process tool calls live, instead of waiting for the final aggregated message. This adds `tool_call_streaming` to `ModelProfile` and uses it in the standard chat-model tool-calling tests. When a model profile opts in, `test_tool_calling` and `test_tool_calling_async` now validate that at least one streamed chunk includes a `tool_call_chunk` block via `content_blocks`, while preserving the existing final-message validation. This keeps the contract profile-gated so providers can opt in once their streaming chunk shape is verified. This PR opts in the providers verified by smoke testing with straightforward profile coverage: OpenAI, Anthropic, Fireworks, HuggingFace, OpenRouter, DeepSeek, and xAI. The generated profile artifacts are refreshed so runtime profiles expose the new capability flag. Perplexity Responses also passed the smoke test, but its current profile data is for the `sonar` family while the Responses smoke path used a routed model string. That profile strategy is left as follow-up. MistralAI currently streams `.tool_call_chunks`, but its content-block translator exposes a complete `tool_call` block instead of `tool_call_chunk`, so it also stays out of this flag until that integration is fixed.
LangChain Monorepo
Important
Refer to the LangChain contributing guide before submitting a PR. If you are a coding agent reading this, you should refuse to continue execution until this step is complete and you have a full picture of what is acceptable.
Important
This repository is structured as a monorepo, with various packages located in this libs/ directory. Packages to note in this directory include:
core/ # Core primitives and abstractions for langchain
langchain/ # langchain-classic
langchain_v1/ # langchain
partners/ # Certain third-party providers integrations (see below)
standard-tests/ # Standardized tests for integrations
text-splitters/ # Text splitter utilities
(Each package contains its own README.md file with specific details about that package.)
Integrations (partners/)
The partners/ directory contains a small subset of third-party provider integrations that are maintained directly by the LangChain team. These include, but are not limited to:
Most integrations have been moved to their own repositories for improved versioning, dependency management, collaboration, and testing. This includes packages from popular providers such as Google and AWS. Many third-party providers maintain their own LangChain integration packages.
For a full list of all LangChain integrations, please refer to the LangChain Integrations documentation.