Implementation:Langchain ai Langchain Pyproject Toml Configuration

Overview

Concrete configuration file for a LangChain partner package, provided by the langchain-deepseek pyproject.toml at libs/partners/deepseek/pyproject.toml.

Description

The pyproject.toml for langchain-deepseek demonstrates the standard configuration structure that every LangChain partner integration package follows. It is organized into the following sections:

Build system: Uses hatchling as the PEP 517 build backend.

Project metadata: Declares the package name (langchain-deepseek), version, description, MIT license, supported Python versions (3.10 through 3.14), and PyPI classifiers.

Runtime dependencies: Requires langchain-core>=1.1.0,<2.0.0 and langchain-openai>=1.1.0,<2.0.0 (since DeepSeek is OpenAI-compatible).

Dependency groups:

test: pytest, pytest-asyncio, pytest-socket (for disabling network in unit tests), pytest-watcher, pytest-timeout, langchain-tests, langchain-openai
test_integration: Empty (no extra deps needed beyond test group)
lint: ruff
typing: mypy

Local development sources ([tool.uv.sources]): Maps langchain-openai, langchain-core, and langchain-tests to local editable paths so that changes are reflected immediately during development.

Tool configurations: Includes settings for mypy (strict untyped defs), ruff (format, lint rules, per-file ignores for tests), pytest (strict markers, asyncio_mode=auto), and coverage.

Usage

Use this file as a reference when creating or modifying the pyproject.toml for any LangChain partner integration package. Copy the structure and adjust the package-specific fields (name, version, description, dependencies).

Code Reference

Source Location: libs/partners/deepseek/pyproject.toml, Lines 1-111

Full configuration:

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[project]
name = "langchain-deepseek"
description = "An integration package connecting DeepSeek and LangChain"
license = { text = "MIT" }
readme = "README.md"
classifiers = [
    "Development Status :: 5 - Production/Stable",
    "Intended Audience :: Developers",
    "License :: OSI Approved :: MIT License",
    "Programming Language :: Python :: 3",
    "Programming Language :: Python :: 3.10",
    "Programming Language :: Python :: 3.11",
    "Programming Language :: Python :: 3.12",
    "Programming Language :: Python :: 3.13",
    "Programming Language :: Python :: 3.14",
    "Topic :: Scientific/Engineering :: Artificial Intelligence",
]

version = "1.1.0"
requires-python = ">=3.10.0,<4.0.0"
dependencies = [
    "langchain-core>=1.1.0,<2.0.0",
    "langchain-openai>=1.1.0,<2.0.0",
]

[project.urls]
Homepage = "https://docs.langchain.com/oss/python/integrations/providers/deepseek"
Documentation = "https://reference.langchain.com/python/integrations/langchain_deepseek/"
Repository = "https://github.com/langchain-ai/langchain"

[dependency-groups]
test = [
    "pytest>=7.4.3,<8.0.0",
    "pytest-asyncio>=0.23.2,<1.0.0",
    "pytest-socket>=0.7.0,<1.0.0",
    "pytest-watcher>=0.3.4,<1.0.0",
    "pytest-timeout>=2.3.1,<3.0.0",
    "langchain-tests",
    "langchain-openai",
]
test_integration = []
lint = ["ruff>=0.13.1,<0.14.0"]
dev = []
typing = ["mypy>=1.10.0,<2.0.0"]

[tool.uv.sources]
langchain-openai = { path = "../openai", editable = true }
langchain-core = { path = "../../core", editable = true }
langchain-tests = { path = "../../standard-tests", editable = true }

[tool.mypy]
disallow_untyped_defs = "True"

[tool.ruff.format]
docstring-code-format = true
docstring-code-line-length = 100

[tool.ruff.lint]
select = [ "ALL" ]

[tool.pytest.ini_options]
addopts = "--strict-markers --strict-config --durations=5"
asyncio_mode = "auto"

[tool.ruff.lint.pydocstyle]
convention = "google"

I/O Contract

Input	Type	Description
`[build-system].requires`	list[str]	Build backend requirement; must be `["hatchling"]`
`[project].name`	str	Package name in `langchain-<name>` format
`[project].version`	str	Semantic version string
`[project].dependencies`	list[str]	Runtime dependencies with version constraints
`[dependency-groups].test`	list[str]	Test-time dependencies including `langchain-tests`

Output	Type	Description
Built wheel	.whl file	Installable Python package
Dependency resolution	uv.lock	Locked dependency graph for reproducible builds
Tool behavior	N/A	Configured linting, formatting, type-checking, and test behavior

Usage Examples

Installing dependencies for a specific group:

# Install test dependencies only
uv sync --group test

# Install all dependency groups
uv sync --all-groups

# Build the package
uv build

Adding a new runtime dependency:

[project]
dependencies = [
    "langchain-core>=1.1.0,<2.0.0",
    "langchain-openai>=1.1.0,<2.0.0",
    "some-new-dependency>=1.0.0,<2.0.0",  # Added
]

Adding a new test dependency:

[dependency-groups]
test = [
    "pytest>=7.4.3,<8.0.0",
    "pytest-asyncio>=0.23.2,<1.0.0",
    "pytest-socket>=0.7.0,<1.0.0",
    "langchain-tests",
    "new-test-helper>=1.0.0",  # Added
]

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