Add cohere partner package structure for API reference documentation

Co-authored-by: mdrxy <61371264+mdrxy@users.noreply.github.com>

libs/partners/cohere/README.md

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+# LangChain Cohere
+
+This package contains the Cohere integrations for LangChain.
+
+## Installation
+
+```bash
+pip install langchain-cohere
+```
+
+## Usage
+
+The `langchain-cohere` package provides integrations for Cohere's language models and embeddings.
+
+### Chat Models
+
+```python
+from langchain_cohere import ChatCohere
+
+chat = ChatCohere(model="command-r-plus")
+```
+
+### Embeddings
+
+```python
+from langchain_cohere import CohereEmbeddings
+
+embeddings = CohereEmbeddings(model="embed-english-v3.0")
+```
+
+### Rerank
+
+```python
+from langchain_cohere import CohereRerank
+
+rerank = CohereRerank(model="rerank-english-v3.0")
+```
+
+For more details, visit the [LangChain Cohere repository](https://github.com/langchain-ai/langchain-cohere).

libs/partners/cohere/langchain_cohere/__init__.py

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+"""Cohere integration package for LangChain.
+
+This package contains the Cohere integrations for LangChain.
+For the full implementation, please install: pip install langchain-cohere
+
+This is a placeholder package to enable API documentation generation.
+"""
+
+# Import from local modules for documentation generation
+from .chat_models import ChatCohere
+from .common import CohereCitation
+from .embeddings import CohereEmbeddings
+from .rag_retrievers import CohereRagRetriever
+from .rerank import CohereRerank
+
+__all__ = [
+    "CohereCitation",
+    "ChatCohere",
+    "CohereEmbeddings",
+    "CohereRagRetriever",
+    "CohereRerank",
+]

libs/partners/cohere/langchain_cohere/chat_models.py

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+"""Chat model for Cohere."""
+
+from typing import Any, Dict, List, Optional, Union
+
+try:
+    from langchain_core.language_models.chat_models import BaseChatModel
+    from langchain_core.messages import BaseMessage
+except ImportError:
+    # Fallback for when langchain_core is not available
+    class BaseChatModel:
+        pass
+    class BaseMessage:
+        pass
+
+
+class ChatCohere(BaseChatModel):
+    """Cohere chat model.
+    
+    To use this, you need to install the ``langchain-cohere`` package.
+    
+    .. code-block:: bash
+    
+        pip install langchain-cohere
+    
+    Example:
+        .. code-block:: python
+        
+            from langchain_cohere import ChatCohere
+            
+            chat = ChatCohere(model="command-r-plus")
+            messages = [("human", "Hello, how are you?")]
+            response = chat.invoke(messages)
+    
+    """
+    
+    model: str = "command-r-plus"
+    """Model name to use."""
+    
+    cohere_api_key: Optional[str] = None
+    """Cohere API key. If not provided, will read from environment variable COHERE_API_KEY."""
+    
+    temperature: float = 0.0
+    """Temperature for sampling."""
+    
+    max_tokens: Optional[int] = None
+    """Maximum number of tokens to generate."""
+    
+    def _generate(
+        self,
+        messages: List[BaseMessage],
+        stop: Optional[List[str]] = None,
+        run_manager: Optional[Any] = None,
+        **kwargs: Any,
+    ) -> Any:
+        """Generate chat completion."""
+        raise NotImplementedError(
+            "This is a placeholder class. Install langchain-cohere to use: pip install langchain-cohere"
+        )
+    
+    @property
+    def _llm_type(self) -> str:
+        """Return type of chat model."""
+        return "cohere-chat"

libs/partners/cohere/langchain_cohere/common.py

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+"""Common utilities and types for Cohere integration."""
+
+from typing import Any, Dict, Optional
+
+
+class CohereCitation:
+    """Represents a citation from Cohere model responses.
+    
+    To use this, you need to install the ``langchain-cohere`` package.
+    
+    .. code-block:: bash
+    
+        pip install langchain-cohere
+    
+    Example:
+        .. code-block:: python
+        
+            from langchain_cohere import CohereCitation
+            
+            citation = CohereCitation(
+                start=0,
+                end=10,
+                text="cited text",
+                document_ids=["doc1"]
+            )
+    
+    """
+    
+    start: int
+    """Start index of the citation in the generated text."""
+    
+    end: int
+    """End index of the citation in the generated text."""
+    
+    text: str
+    """The cited text."""
+    
+    document_ids: list[str]
+    """List of document IDs that support this citation."""
+    
+    def __init__(
+        self,
+        start: int,
+        end: int,
+        text: str,
+        document_ids: list[str],
+        **kwargs: Any,
+    ) -> None:
+        """Initialize citation."""
+        self.start = start
+        self.end = end
+        self.text = text
+        self.document_ids = document_ids

libs/partners/cohere/langchain_cohere/embeddings.py

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+"""Cohere embeddings."""
+
+from typing import List, Optional
+
+try:
+    from langchain_core.embeddings import Embeddings
+except ImportError:
+    # Fallback for when langchain_core is not available
+    class Embeddings:
+        pass
+
+
+class CohereEmbeddings(Embeddings):
+    """Cohere embeddings.
+    
+    To use this, you need to install the ``langchain-cohere`` package.
+    
+    .. code-block:: bash
+    
+        pip install langchain-cohere
+    
+    Example:
+        .. code-block:: python
+        
+            from langchain_cohere import CohereEmbeddings
+            
+            embeddings = CohereEmbeddings(model="embed-english-v3.0")
+            text_embeddings = embeddings.embed_documents(["Hello world"])
+    
+    """
+    
+    model: str = "embed-english-v3.0"
+    """Model name to use."""
+    
+    cohere_api_key: Optional[str] = None
+    """Cohere API key. If not provided, will read from environment variable COHERE_API_KEY."""
+    
+    def embed_documents(self, texts: List[str]) -> List[List[float]]:
+        """Embed search docs."""
+        raise NotImplementedError(
+            "This is a placeholder class. Install langchain-cohere to use: pip install langchain-cohere"
+        )
+    
+    def embed_query(self, text: str) -> List[float]:
+        """Embed query text."""
+        raise NotImplementedError(
+            "This is a placeholder class. Install langchain-cohere to use: pip install langchain-cohere"
+        )

libs/partners/cohere/langchain_cohere/rag_retrievers.py

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+"""Cohere RAG retriever."""
+
+from typing import Any, List, Optional
+
+try:
+    from langchain_core.documents import Document
+    from langchain_core.retrievers import BaseRetriever
+except ImportError:
+    # Fallback for when langchain_core is not available
+    class Document:
+        pass
+    class BaseRetriever:
+        pass
+
+
+class CohereRagRetriever(BaseRetriever):
+    """Cohere RAG retriever.
+    
+    To use this, you need to install the ``langchain-cohere`` package.
+    
+    .. code-block:: bash
+    
+        pip install langchain-cohere
+    
+    Example:
+        .. code-block:: python
+        
+            from langchain_cohere import CohereRagRetriever
+            
+            retriever = CohereRagRetriever()
+            docs = retriever.get_relevant_documents("query")
+    
+    """
+    
+    cohere_api_key: Optional[str] = None
+    """Cohere API key. If not provided, will read from environment variable COHERE_API_KEY."""
+    
+    def _get_relevant_documents(
+        self,
+        query: str,
+        *,
+        run_manager: Optional[Any] = None,
+    ) -> List[Document]:
+        """Get documents relevant to a query."""
+        raise NotImplementedError(
+            "This is a placeholder class. Install langchain-cohere to use: pip install langchain-cohere"
+        )

libs/partners/cohere/langchain_cohere/rerank.py

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+"""Cohere rerank functionality."""
+
+from typing import Any, List, Optional, Sequence
+
+try:
+    from langchain_core.documents import Document
+except ImportError:
+    # Fallback for when langchain_core is not available
+    class Document:
+        pass
+
+
+class CohereRerank:
+    """Cohere rerank model.
+    
+    To use this, you need to install the ``langchain-cohere`` package.
+    
+    .. code-block:: bash
+    
+        pip install langchain-cohere
+    
+    Example:
+        .. code-block:: python
+        
+            from langchain_cohere import CohereRerank
+            
+            rerank = CohereRerank(model="rerank-english-v3.0")
+            docs = [Document(page_content="doc1"), Document(page_content="doc2")]
+            reranked = rerank.rerank(docs, "query")
+    
+    """
+    
+    model: str = "rerank-english-v3.0"
+    """Model name to use."""
+    
+    cohere_api_key: Optional[str] = None
+    """Cohere API key. If not provided, will read from environment variable COHERE_API_KEY."""
+    
+    top_n: int = 10
+    """Number of documents to return."""
+    
+    def rerank(
+        self,
+        documents: Sequence[Document],
+        query: str,
+        **kwargs: Any,
+    ) -> List[Document]:
+        """Rerank documents based on query relevance."""
+        raise NotImplementedError(
+            "This is a placeholder class. Install langchain-cohere to use: pip install langchain-cohere"
+        )

libs/partners/cohere/pyproject.toml

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+[build-system]
+requires = ["poetry-core>=1.0.0"]
+build-backend = "poetry.core.masonry.api"
+
+[project]
+name = "langchain-cohere"
+version = "0.4.4"
+description = "An integration package connecting Cohere and LangChain"
+readme = "README.md"
+license = {text = "MIT"}
+dependencies = [
+    "langchain-core>=0.3.27",
+    "cohere>=5.12.0,<6.0",
+    "langchain-community>=0.3.0",
+    "pydantic>=2,<3",
+]
+authors = [
+    {name = "LangChain", email = "hello@langchain.com"}
+]
+
+[project.urls]
+"Source Code" = "https://github.com/langchain-ai/langchain-cohere"
+"Homepage" = "https://github.com/langchain-ai/langchain-cohere"
+
+[tool.poetry]
+name = "langchain-cohere"
+version = "0.4.4"
+description = "An integration package connecting Cohere and LangChain"
+authors = []
+readme = "README.md"
+repository = "https://github.com/langchain-ai/langchain-cohere"
+license = "MIT"
+
+[tool.poetry.urls]
+"Source Code" = "https://github.com/langchain-ai/langchain-cohere"
+
+[tool.poetry.dependencies]
+python = ">=3.9,<4.0"
+langchain-core = "^0.3.27"
+cohere = ">=5.12.0,<6.0"
+langchain-community = { version = "^0.3.0"}
+pydantic = ">=2,<3"
+
+[tool.poetry.group.test]
+optional = true
+
+[tool.poetry.group.test.dependencies]
+pytest = "^8.2.2"
+freezegun = "^1.2.2"
+pytest-mock = "^3.10.0"
+syrupy = "^4.0.2"
+pytest-watcher = "^0.3.4"
+pytest-asyncio = "^0.21.1"
+langchain-tests = "0.3.1"
+
+[tool.poetry.group.codespell]
+optional = true
+
+[tool.poetry.group.codespell.dependencies]
+codespell = "^2.2.0"
+
+[tool.poetry.group.lint]
+optional = true
+
+[tool.poetry.group.lint.dependencies]
+ruff = "^0.1.5"
+
+[tool.poetry.group.typing.dependencies]
+mypy = "^0.991"
+
+[tool.ruff]
+select = [
+  "E", # pycodestyle
+  "F", # pyflakes
+  "I", # isort
+]
+
+fixable = ["ALL"]
+
+[tool.mypy]
+disallow_untyped_defs = true
+
+[tool.coverage.run]
+omit = ["tests/*"]
+
+[tool.pytest.ini_options]
+addopts = "--snapshot-warn-unused --strict-markers --strict-config --durations=5"
+markers = [
+  "requires: mark tests as requiring a specific library",
+  "asyncio: mark tests as requiring asyncio",
+  "compile: mark placeholder test used to compile integration tests without running them",
+]
+asyncio_mode = "auto"