Support static context in integration with langchain

[benlangfeld]

This is used to store data about an agent invocation which should be accessible to tools but not to the LLM, like API keys, user IDs etc.

See:

• https://docs.langchain.com/oss/python/langchain/context-engineering#runtime-context-6
• feat(langgraph): new context api (replacing config['configurable'] and config_schema) langchain-ai/langgraph#5243

[CLAassistant]

All committers have signed the CLA.

[davidzhao]

this looks good, could you roll back the uv.lock change and fix the types CI please?

[benlangfeld]

this looks good, could you roll back the uv.lock change and fix the types CI please?

I cannot roll back the uv.lock change, because this feature was introduced in langgraph 0.6.0.

I am trying to fix the type error, it's not clear to me why it's occurring right now. The dependency upgrade should have fixed it.

uv run python
Python 3.12.4 (main, Jul  1 2024, 18:16:41) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from typing import get_type_hints
>>> from langgraph.pregel.protocol import PregelProtocol
>>> get_type_hints(PregelProtocol.astream)['context']
typing.Optional[~ContextT]

The type error raised by mypy is wrong. I am not really a python developer, so I'd appreciate any help in figuring out why it might be happening.

[bcdonadio]

@benlangfeld This should fix it: powerhome#3

[benlangfeld]

@davidzhao This should be ready to go.

[davidzhao]

lg!