langchain-ai/langgraph · error · ValueError

EmbeddingsLambda was initialized with an async function but

Error message

EmbeddingsLambda was initialized with an async function but no sync function. Use aembed_documents for async operation or provide a sync function.

What it means

Error "EmbeddingsLambda was initialized with an async function but no sync function. Use aembed_documents for async operation or provide a sync function." thrown in langchain-ai/langgraph.

Source

Thrown at libs/checkpoint/langgraph/checkpoint/store/base/embed.py:176

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/checkpoint/langgraph/checkpoint/store/base/embed.py:176 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langchain-ai/langgraph@38031739e5 (2026-08-26). Data as JSON: /api/errors/20fa876486e101cb. Report an issue: GitHub.