Add comprehensive docstrings to LanceDB adapter

- Add Google-style docstrings to all public functions and classes in lancedb_adapter.py
- Include Args, Returns, Raises, and Example sections where appropriate
- Add test file to verify docstrings exist for all public API methods
- Addresses issue #3955

Co-Authored-By: João <joao@crewai.com>

lib/crewai-tools/src/crewai_tools/adapters/lancedb_adapter.py

@@ -14,6 +14,22 @@ from crewai_tools.tools.rag.rag_tool import Adapter
 
 
 def _default_embedding_function():
+    """Create a default embedding function using OpenAI's text-embedding-ada-002 model.
+
+    This function creates and returns an embedding function that uses OpenAI's API
+    to generate embeddings for text inputs. The embedding function is used by the
+    LanceDBAdapter to convert text queries into vector representations for similarity search.
+
+    Returns:
+        Callable: A function that takes a list of strings and returns their embeddings
+            as a list of vectors.
+
+    Example:
+        >>> embed_fn = _default_embedding_function()
+        >>> embeddings = embed_fn(["Hello world"])
+        >>> len(embeddings[0])  # Vector dimension
+        1536
+    """
     client = OpenAIClient()
 
     def _embedding_function(input):
@@ -24,6 +40,32 @@ def _default_embedding_function():
 
 
 class LanceDBAdapter(Adapter):
+    """Adapter for integrating LanceDB vector database with CrewAI RAG tools.
+
+    LanceDBAdapter provides a bridge between CrewAI's RAG (Retrieval-Augmented Generation)
+    system and LanceDB, enabling efficient vector similarity search for knowledge retrieval.
+    It handles embedding generation, vector search, and data ingestion with precise control
+    over query parameters and column mappings.
+
+    Attributes:
+        uri: Database connection URI or path to the LanceDB database.
+        table_name: Name of the table to query within the LanceDB database.
+        embedding_function: Function to convert text into embeddings. Defaults to OpenAI's
+            text-embedding-ada-002 model.
+        top_k: Number of top results to return from similarity search. Defaults to 3.
+        vector_column_name: Name of the column containing vector embeddings. Defaults to "vector".
+        text_column_name: Name of the column containing text content. Defaults to "text".
+
+    Example:
+        >>> from crewai_tools.adapters.lancedb_adapter import LanceDBAdapter
+        >>> adapter = LanceDBAdapter(
+        ...     uri="./my_lancedb",
+        ...     table_name="documents",
+        ...     top_k=5
+        ... )
+        >>> results = adapter.query("What is machine learning?")
+        >>> print(results)
+    """
     uri: str | Path
     table_name: str
     embedding_function: Callable = Field(default_factory=_default_embedding_function)
@@ -35,12 +77,44 @@ class LanceDBAdapter(Adapter):
     _table: LanceDBTable = PrivateAttr()
 
     def model_post_init(self, __context: Any) -> None:
+        """Initialize the database connection and table after model instantiation.
+
+        This method is automatically called after the Pydantic model is initialized.
+        It establishes the connection to the LanceDB database and opens the specified
+        table for querying and data operations.
+
+        Args:
+            __context: Pydantic context object passed during initialization.
+
+        Raises:
+            Exception: If the database connection fails or the table does not exist.
+        """
         self._db = lancedb_connect(self.uri)
         self._table = self._db.open_table(self.table_name)
 
         super().model_post_init(__context)
 
     def query(self, question: str) -> str:  # type: ignore[override]
+        """Perform a vector similarity search for the given question.
+
+        This method converts the input question into an embedding vector and searches
+        the LanceDB table for the most similar entries. It returns the top-k results
+        based on vector similarity, providing precise retrieval for RAG applications.
+
+        Args:
+            question: The text query to search for in the vector database.
+
+        Returns:
+            A string containing the concatenated text results from the top-k most
+            similar entries, separated by newlines.
+
+        Example:
+            >>> adapter = LanceDBAdapter(uri="./db", table_name="docs")
+            >>> results = adapter.query("What is CrewAI?")
+            >>> print(results)
+            CrewAI is a framework for orchestrating AI agents...
+            CrewAI provides precise control over agent workflows...
+        """
         query = self.embedding_function([question])[0]
         results = (
             self._table.search(query, vector_column_name=self.vector_column_name)
@@ -56,4 +130,23 @@ class LanceDBAdapter(Adapter):
         *args: Any,
         **kwargs: Any,
     ) -> None:
+        """Add data to the LanceDB table.
+
+        This method provides a direct interface to add new records to the underlying
+        LanceDB table. It accepts the same arguments as the LanceDB table's add method,
+        allowing flexible data ingestion for building knowledge bases.
+
+        Args:
+            *args: Positional arguments to pass to the LanceDB table's add method.
+            **kwargs: Keyword arguments to pass to the LanceDB table's add method.
+                Common kwargs include 'data' (list of records) and 'mode' (append/overwrite).
+
+        Example:
+            >>> adapter = LanceDBAdapter(uri="./db", table_name="docs")
+            >>> data = [
+            ...     {"text": "CrewAI enables agent collaboration", "vector": [0.1, 0.2, ...]},
+            ...     {"text": "LanceDB provides vector storage", "vector": [0.3, 0.4, ...]}
+            ... ]
+            >>> adapter.add(data=data)
+        """
         self._table.add(*args, **kwargs)

lib/crewai-tools/tests/adapters/test_lancedb_adapter_docs.py

@@ -0,0 +1,62 @@
+"""Test that LanceDB adapter has proper docstrings."""
+
+import inspect
+
+import pytest
+
+lancedb = pytest.importorskip("lancedb")
+
+from crewai_tools.adapters.lancedb_adapter import (
+    LanceDBAdapter,
+    _default_embedding_function,
+)
+
+
+def test_lancedb_adapter_class_has_docstring():
+    """Verify that LanceDBAdapter class has a docstring."""
+    assert LanceDBAdapter.__doc__ is not None, "LanceDBAdapter class is missing a docstring"
+    assert len(LanceDBAdapter.__doc__.strip()) > 0, "LanceDBAdapter docstring is empty"
+
+
+def test_lancedb_adapter_model_post_init_has_docstring():
+    """Verify that model_post_init method has a docstring."""
+    assert (
+        LanceDBAdapter.model_post_init.__doc__ is not None
+    ), "model_post_init method is missing a docstring"
+    assert (
+        len(LanceDBAdapter.model_post_init.__doc__.strip()) > 0
+    ), "model_post_init docstring is empty"
+
+
+def test_lancedb_adapter_query_has_docstring():
+    """Verify that query method has a docstring."""
+    assert LanceDBAdapter.query.__doc__ is not None, "query method is missing a docstring"
+    assert len(LanceDBAdapter.query.__doc__.strip()) > 0, "query docstring is empty"
+
+
+def test_lancedb_adapter_add_has_docstring():
+    """Verify that add method has a docstring."""
+    assert LanceDBAdapter.add.__doc__ is not None, "add method is missing a docstring"
+    assert len(LanceDBAdapter.add.__doc__.strip()) > 0, "add docstring is empty"
+
+
+def test_default_embedding_function_has_docstring():
+    """Verify that _default_embedding_function has a docstring."""
+    assert (
+        _default_embedding_function.__doc__ is not None
+    ), "_default_embedding_function is missing a docstring"
+    assert (
+        len(_default_embedding_function.__doc__.strip()) > 0
+    ), "_default_embedding_function docstring is empty"
+
+
+def test_docstrings_contain_required_sections():
+    """Verify that docstrings contain Args, Returns, or Example sections where appropriate."""
+    query_doc = LanceDBAdapter.query.__doc__
+    assert query_doc is not None
+    assert "Args:" in query_doc or "Parameters:" in query_doc, "query docstring should have Args/Parameters section"
+    assert "Returns:" in query_doc, "query docstring should have Returns section"
+
+    add_doc = LanceDBAdapter.add.__doc__
+    assert add_doc is not None
+    assert "Args:" in add_doc or "Parameters:" in add_doc, "add docstring should have Args/Parameters section"