cf08ef0a29
Fixes #36581 ## Problem `ChatOpenRouter` had no way to set custom HTTP headers on requests to OpenRouter. Passing `default_headers` to the constructor silently misfired: `build_extra` treated it as an unrecognized kwarg, emitted a "transferred to model_kwargs" warning, and dumped the header into the request body instead of the HTTP layer. This blocked any feature that needs per-request header injection — for example xAI's `x-grok-conv-id` for sticky-routing prompt cache hits. ## What changed - `default_headers` is now a first-class field on `ChatOpenRouter` (`Mapping[str, str] | None`). Because headers may carry credentials, the field is excluded from serialization. - User-supplied headers are merged with the built-in app-attribution headers (`HTTP-Referer`, `X-Title`, `X-OpenRouter-Categories`). On collision the user value wins; because HTTP header names are case-insensitive, the merge drops any built-in whose name case-insensitively matches a user header before applying, so `http-referer` replaces `HTTP-Referer` rather than producing a doubled header. - Corrected the documented `session_id` length limit from 128 to 256 characters. Example: ChatOpenRouter( model="x-ai/grok-4", default_headers={"x-grok-conv-id": "session-abc123"}, ) --------- Co-authored-by: Mason Daugherty <github@mdrxy.com>
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.