diff --git a/langchain/chains/research/fetch.py b/langchain/chains/research/download.py
similarity index 92%
rename from langchain/chains/research/fetch.py
rename to langchain/chains/research/download.py
index 372dfb1f4f1..e0448829b24 100644
--- a/langchain/chains/research/fetch.py
+++ b/langchain/chains/research/download.py
@@ -15,6 +15,7 @@ import abc
 import asyncio
 import mimetypes
 from typing import Any, List, Optional, Sequence
+from pydantic import ValidationError
 
 from bs4 import BeautifulSoup
 
@@ -109,10 +110,18 @@ class RequestsDownloadHandler(DownloadHandler):
 
 def _repackage_as_blobs(urls: Sequence[str], contents: Sequence[str]) -> List[Blob]:
     """Repackage the contents as blobs."""
-    return [
-        Blob(data=content, mimetype=mimetypes.guess_type(url)[0], path=url)
-        for url, content in zip(urls, contents)
-    ]
+    blobs = []
+    for url, content in zip(urls, contents):
+        mimetype = mimetypes.guess_type(url)[0]
+        try:
+            blobs.append(Blob(data=content, mimetype=mimetype, path=url))
+        except ValidationError:
+            raise ValueError(
+                f"Could not create a blob for content at {url}. "
+                f"Content type is {type(content)}"
+            )
+
+    return blobs
 
 
 class AutoDownloadHandler(DownloadHandler):
diff --git a/langchain/chains/research/typedefs.py b/langchain/chains/research/typedefs.py
index acfbaee0190..8cb7d4ec37d 100644
--- a/langchain/chains/research/typedefs.py
+++ b/langchain/chains/research/typedefs.py
@@ -1,55 +1,12 @@
 import abc
-from typing import Any, List, Mapping, Sequence
+from typing import List
 
-from langchain.callbacks.manager import Callbacks
 from langchain.document_loaders.blob_loaders import Blob
 
-#
-# class AbstractQueryGenerator(abc.ABC):
-#     """Abstract class for generating queries."""
-#
-#     @abc.abstractmethod
-#     def generate_queries(self, question: str, callbacks: Callbacks = None) -> List[str]:
-#         """Generate queries for the given question."""
-#         raise NotImplementedError()
-#
-#     @abc.abstractmethod
-#     async def agenerate_queries(
-#         self, question: str, callbacks: Callbacks = None
-#     ) -> List[str]:
-#         """Generate queries for the given question."""
-#         raise NotImplementedError()
-#
-#
-# class AbstractSearcher(abc.ABC):
-#     """Abstract class for running searches."""
-#
-#     def search(self, queries: Sequence[str]) -> List[Mapping[str, Any]]:
-#         """Run a search for the given query.
-#
-#         Args:
-#             queries: the query to run the search for.
-#
-#         Returns:
-#             a list of search results.
-#         """
-#         raise NotImplementedError()
-#
-#     async def asearch(self, queries: Sequence[str]) -> List[Mapping[str, Any]]:
-#         """Run a search for the given query.
-#
-#         Args:
-#             queries: the query to run the search for.
-#
-#         Returns:
-#             a list of search results.
-#         """
-#         raise NotImplementedError()
-#
-#
-# class BlobCrawler(abc.ABC):
-#     """Crawl a blob and identify links to related content."""
-#
-#     @abc.abstractmethod
-#     def crawl(self, blob: Blob, query: str, callbacks: Callbacks = None) -> List[str]:
-#         """Explore the blob and identify links to related content that is relevant to the query."""
+
+class BlobCrawler(abc.ABC):
+    """Crawl a blob and identify links to related content."""
+
+    @abc.abstractmethod
+    def crawl(self, blob: Blob, query: str) -> List[str]:
+        """Explore the blob and identify links to relevant content."""