feat(anthropic): web fetch beta (#32894)

Note: citations are broken until Anthropic fixes their API

Author: mdrxy

docs/docs/integrations/chat/anthropic.ipynb

@@ -970,8 +970,8 @@
    "source": [
     "### In tool results (agentic RAG)\n",
     "\n",
-    ":::info Requires ``langchain-anthropic>=0.3.17``\n",
-    "\n",
+    ":::info\n",
+    "Requires ``langchain-anthropic>=0.3.17``\n",
     ":::\n",
     "\n",
     "Claude supports a [search_result](https://docs.anthropic.com/en/docs/build-with-claude/search-results) content block representing citable results from queries against a knowledge base or other custom source. These content blocks can be passed to claude both top-line (as in the above example) and within a tool result. This allows Claude to cite elements of its response using the result of a tool call.\n",
@@ -1290,6 +1290,58 @@
     "print(f\"Key Points: {result.key_points}\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "c580c20a",
+   "metadata": {},
+   "source": [
+    "### Web fetching\n",
+    "\n",
+    "Claude can use a [web fetching tool](https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/web-fetch-tool) to run searches and ground its responses with citations."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "5cf6ad08",
+   "metadata": {},
+   "source": [
+    ":::info\n",
+    "Web search tool is supported since ``langchain-anthropic>=0.3.20``\n",
+    ":::"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c4804be1",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain_anthropic import ChatAnthropic\n",
+    "\n",
+    "llm = ChatAnthropic(\n",
+    "    model=\"claude-3-5-haiku-latest\",\n",
+    "    betas=[\"web-fetch-2025-09-10\"],  # Enable web fetch beta\n",
+    ")\n",
+    "\n",
+    "tool = {\"type\": \"web_fetch_20250910\", \"name\": \"web_fetch\", \"max_uses\": 3}\n",
+    "llm_with_tools = llm.bind_tools([tool])\n",
+    "\n",
+    "response = llm_with_tools.invoke(\n",
+    "    \"Please analyze the content at https://example.com/article\"\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "088c41d0",
+   "metadata": {},
+   "source": [
+    ":::warning\n",
+    "Note: you must add the `'web-fetch-2025-09-10'` beta header to use this tool.\n",
+    ":::"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "1478cdc6-2e52-4870-80f9-b4ddf88f2db2",
@@ -1299,14 +1351,14 @@
     "\n",
     "Claude can use a [code execution tool](https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/code-execution-tool) to execute Python code in a sandboxed environment.\n",
     "\n",
-    ":::info Code execution is supported since ``langchain-anthropic>=0.3.14``\n",
-    "\n",
+    ":::info\n",
+    "Code execution is supported since ``langchain-anthropic>=0.3.14``\n",
     ":::"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "id": "2ce13632-a2da-439f-a429-f66481501630",
    "metadata": {},
    "outputs": [],
@@ -1315,7 +1367,7 @@
     "\n",
     "llm = ChatAnthropic(\n",
     "    model=\"claude-sonnet-4-20250514\",\n",
-    "    betas=[\"code-execution-2025-05-22\"],\n",
+    "    betas=[\"code-execution-2025-05-22\"],  # Enable code execution beta\n",
     ")\n",
     "\n",
     "tool = {\"type\": \"code_execution_20250522\", \"name\": \"code_execution\"}\n",
@@ -1326,6 +1378,16 @@
     ")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "a6b5e15a",
+   "metadata": {},
+   "source": [
+    ":::warning\n",
+    "Note: you must add the `'code_execution_20250522'` beta header to use this tool.\n",
+    ":::"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "24076f91-3a3d-4e53-9618-429888197061",
@@ -1404,14 +1466,14 @@
     "\n",
     "Claude can use a [MCP connector tool](https://docs.anthropic.com/en/docs/agents-and-tools/mcp-connector) for model-generated calls to remote MCP servers.\n",
     "\n",
-    ":::info Remote MCP is supported since ``langchain-anthropic>=0.3.14``\n",
-    "\n",
+    ":::info\n",
+    "Remote MCP is supported since ``langchain-anthropic>=0.3.14``\n",
     ":::"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "id": "22fc4a89-e6d8-4615-96cb-2e117349aebf",
    "metadata": {},
    "outputs": [],
@@ -1423,17 +1485,17 @@
     "        \"type\": \"url\",\n",
     "        \"url\": \"https://mcp.deepwiki.com/mcp\",\n",
     "        \"name\": \"deepwiki\",\n",
-    "        \"tool_configuration\": {  # optional configuration\n",
+    "        \"tool_configuration\": {  # Optional configuration\n",
     "            \"enabled\": True,\n",
     "            \"allowed_tools\": [\"ask_question\"],\n",
     "        },\n",
-    "        \"authorization_token\": \"PLACEHOLDER\",  # optional authorization\n",
+    "        \"authorization_token\": \"PLACEHOLDER\",  # Optional authorization\n",
     "    }\n",
     "]\n",
     "\n",
     "llm = ChatAnthropic(\n",
     "    model=\"claude-sonnet-4-20250514\",\n",
-    "    betas=[\"mcp-client-2025-04-04\"],\n",
+    "    betas=[\"mcp-client-2025-04-04\"],  # Enable MCP beta\n",
     "    mcp_servers=mcp_servers,\n",
     ")\n",
     "\n",
@@ -1443,6 +1505,16 @@
     ")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "0d6d7197",
+   "metadata": {},
+   "source": [
+    ":::warning\n",
+    "Note: you must add the `'mcp-client-2025-04-04'` beta header to use this tool.\n",
+    ":::"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "2fd5d545-a40d-42b1-ad0c-0a79e2536c9b",

libs/partners/anthropic/langchain_anthropic/chat_models.py

@@ -71,6 +71,10 @@ class AnthropicTool(TypedDict):
 
 
 def _is_builtin_tool(tool: Any) -> bool:
+    """Check if a tool is a built-in Anthropic tool.
+
+    https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/overview
+    """
     if not isinstance(tool, dict):
         return False
 
@@ -83,6 +87,7 @@ def _is_builtin_tool(tool: Any) -> bool:
         "computer_",
         "bash_",
         "web_search_",
+        "web_fetch_",
         "code_execution_",
     ]
     return any(tool_type.startswith(prefix) for prefix in _builtin_tool_prefixes)
@@ -277,16 +282,7 @@ def _format_data_content_block(block: dict) -> dict:
 def _format_messages(
     messages: Sequence[BaseMessage],
 ) -> tuple[Union[str, list[dict], None], list[dict]]:
-    """Format messages for anthropic."""
-    """
-    [
-                {
-                    "role": _message_type_lookups[m.type],
-                    "content": [_AnthropicMessageContent(text=m.content).model_dump()],
-                }
-                for m in messages
-            ]
-    """
+    """Format messages for Anthropic's API."""
     system: Union[str, list[dict], None] = None
     formatted_messages: list[dict] = []
     merged_messages = _merge_messages(messages)
@@ -440,6 +436,7 @@ def _format_messages(
                         "code_execution_tool_result",
                         "mcp_tool_result",
                         "web_search_tool_result",
+                        "web_fetch_tool_result",
                     ):
                         content.append(
                             {
@@ -452,6 +449,7 @@ def _format_messages(
                                     "tool_use_id",
                                     "is_error",  # for mcp_tool_result
                                     "cache_control",
+                                    "retrieved_at",  # for web_fetch_tool_result
                                 )
                             },
                         )
@@ -1137,6 +1135,24 @@ def get_weather(location: str) -> str:
                     "How do I update a web app to TypeScript 5.5?"
                 )
 
+        .. dropdown::  Web fetch (beta)
+
+            .. code-block:: python
+
+                from langchain_anthropic import ChatAnthropic
+
+                llm = ChatAnthropic(
+                    model="claude-3-5-haiku-latest",
+                    betas=["web-fetch-2025-09-10"],  # Enable web fetch beta
+                )
+
+                tool = {"type": "web_fetch_20250910", "name": "web_fetch", "max_uses": 3}
+                llm_with_tools = llm.bind_tools([tool])
+
+                response = llm_with_tools.invoke(
+                    "Please analyze the content at https://example.com/article"
+                )
+
         .. dropdown::  Code execution
 
             .. code-block:: python
@@ -2232,6 +2248,7 @@ def _make_message_chunk_from_anthropic_event(
             "mcp_tool_result",
             "server_tool_use",  # Server-side tool usage
             "web_search_tool_result",  # Built-in web search results
+            "web_fetch_tool_result",  # Built-in web fetch results,
         )
     ):
         if coerce_content_to_string:

libs/partners/anthropic/pyproject.toml

@@ -7,8 +7,8 @@ authors = []
 license = { text = "MIT" }
 requires-python = ">=3.9"
 dependencies = [
-    "anthropic<1,>=0.64.0",
-    "langchain-core<1.0.0,>=0.3.74",
+    "anthropic<1,>=0.67.0",
+    "langchain-core<1.0.0,>=0.3.76",
     "pydantic<3.0.0,>=2.7.4",
 ]
 name = "langchain-anthropic"