bfc65cc04f
## Summary - Fix `ChatAnthropic._make_message_chunk_from_anthropic_event` dropping the first text chunk of an assistant turn when Anthropic carries the opening text on the `content_block_start` event rather than a following `text_delta`. This most often hits the assistant turn right after a tool result. - The dropped content streams to clients but never reaches the aggregated `AIMessage`, so anything reading message history back (e.g. a checkpointer) sees a truncated message (`Here's the answer.` → `'s the answer.`). Reported via Pylon 25478 (Zip), whose `<canvaspreview>` parser broke because the dropped chunk was the opening `<can` tag. - Add a `content_block_start` branch for `text` and `thinking` blocks: emit non-empty start-event content on both the string (`coerce_content_to_string=True`) and structured content paths; empty starts still emit no chunk (preserving prior behavior) and update `block_start_event` so following deltas resolve against the current block. --------- Co-authored-by: Mason Daugherty <mason@langchain.dev> 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.