1de100f278
Originally a narrow bump of mypy to `1.20` in four packages. Expanded to get the whole monorepo onto a single, current mypy and a consistent type-check configuration, so contributors no longer hit different mypy versions and divergent behavior depending on which package they touch. ### What changed - **Unified the mypy pin to `>=2.1.0,<2.2.0`** in every mypy-using package (6 libs + 14 partners), replacing the previously scattered pins (`1.10`/`1.17`/`1.18`/`1.19`/`1.20`, with assorted upper bounds). - **Unified the `[tool.mypy]` base per tier:** - libs: `plugins = ["pydantic.mypy"]`, `strict = true`, `enable_error_code = "deprecated"`, `warn_unreachable = true` - partners: `disallow_untyped_defs = true` - Normalized style (`disallow_untyped_defs = "True"` string → bool, quote/key consistency). - **Fixed the 20 real errors** mypy 2.1 surfaces: `redundant-cast` from improved narrowing (`core`, `langchain-classic`), a `var-annotated` for `_LOGGED`, a return-type widening in `langchain-groq`'s `_convert_from_v1_to_groq` (it can legitimately return a bare `str`), and stale `type-arg`/`unused-ignore` in `langchain-model-profiles` tests. ### Deliberate non-uniformity (documented inline in the relevant `pyproject.toml`s) Going fully byte-identical would surface ~196 additional errors that are *not* real bugs, so two settings are kept package-appropriate: - **`warn_unreachable`** is enabled on every strict lib **except `core`**, where it false-flags intentional defensive code — including the SSRF / IP-policy guards in `_security/` — as unreachable. - **`pydantic.mypy` plugin** is used only on `anthropic` and `perplexity` (their code is authored against it and reports ~99/~132 errors without it). It is *not* added to the other partners, where it only flags the public alias constructor API (e.g. `ChatGroq(model=...)`) in tests rather than finding bugs. - **`ollama`** is left on its `ty` type checker; it does not use mypy. --------- Co-authored-by: Mason Daugherty <github@mdrxy.com>
🦜🍎️ LangChain Core
Looking for the JS/TS version? Check out LangChain.js.
To help you ship LangChain apps to production faster, check out LangSmith. LangSmith is a unified developer platform for building, testing, and monitoring LLM applications.
Quick Install
pip install langchain-core
🤔 What is this?
LangChain Core contains the base abstractions that power the LangChain ecosystem.
These abstractions are designed to be as modular and simple as possible.
The benefit of having these abstractions is that any provider can implement the required interface and then easily be used in the rest of the LangChain ecosystem.
⛰️ Why build on top of LangChain Core?
The LangChain ecosystem is built on top of langchain-core. Some of the benefits:
- Modularity: We've designed Core around abstractions that are independent of each other, and not tied to any specific model provider.
- Stability: We are committed to a stable versioning scheme, and will communicate any breaking changes with advance notice and version bumps.
- Battle-tested: Core components have the largest install base in the LLM ecosystem, and are used in production by many companies.
📖 Documentation
For full documentation, see the API reference. For conceptual guides, tutorials, and examples on using LangChain, see the LangChain Docs. You can also chat with the docs using Chat LangChain.
📕 Releases & Versioning
See our Releases and Versioning policies.
💁 Contributing
As an open-source project in a rapidly developing field, we are extremely open to contributions, whether it be in the form of a new feature, improved infrastructure, or better documentation.
For detailed information on how to contribute, see the Contributing Guide.