From cf6c277386295090a411f0ea6040d71b390dddef Mon Sep 17 00:00:00 2001
From: 0xxmemo <mguleryuz3@gmail.com>
Date: Mon, 6 Apr 2026 15:56:14 -0500
Subject: [PATCH] Add support for server_tool_use and web_search_tool_result in
 FakeAnthropicMessagesStreamIterator

- Implemented handling for "server_tool_use" and "web_search_tool_result" block types in the FakeAnthropicMessagesStreamIterator.
- Added logic to emit content_block_start and content_block_stop events for both block types, aligning with Anthropic's native streaming format.
- Enhanced the iterator's functionality to support new message types, improving integration with external tools.
---
 .../messages/fake_stream_iterator.py          | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/litellm/llms/anthropic/experimental_pass_through/messages/fake_stream_iterator.py b/litellm/llms/anthropic/experimental_pass_through/messages/fake_stream_iterator.py
index 7fc9b00f2c7..9dde357f4ee 100644
--- a/litellm/llms/anthropic/experimental_pass_through/messages/fake_stream_iterator.py
+++ b/litellm/llms/anthropic/experimental_pass_through/messages/fake_stream_iterator.py
@@ -169,6 +169,42 @@ class FakeAnthropicMessagesStreamIterator:
             block_dict = cast(Dict[str, Any], block)
             chunks.extend(self._create_content_block_chunks(block_dict, index))
 
+                elif block_type == "server_tool_use":
+                    # Emit the full block as content_block_start (same as
+                    # Anthropic's native streaming format).
+                    content_block_start = {
+                        "type": "content_block_start",
+                        "index": index,
+                        "content_block": block_dict,
+                    }
+                    chunks.append(
+                        f"event: content_block_start\ndata: {json.dumps(content_block_start)}\n\n".encode()
+                    )
+
+                    # content_block_stop
+                    content_block_stop = {"type": "content_block_stop", "index": index}
+                    chunks.append(
+                        f"event: content_block_stop\ndata: {json.dumps(content_block_stop)}\n\n".encode()
+                    )
+
+                elif block_type == "web_search_tool_result":
+                    # Emit the full block as content_block_start (same as
+                    # Anthropic's native streaming format).
+                    content_block_start = {
+                        "type": "content_block_start",
+                        "index": index,
+                        "content_block": block_dict,
+                    }
+                    chunks.append(
+                        f"event: content_block_start\ndata: {json.dumps(content_block_start)}\n\n".encode()
+                    )
+
+                    # content_block_stop
+                    content_block_stop = {"type": "content_block_stop", "index": index}
+                    chunks.append(
+                        f"event: content_block_stop\ndata: {json.dumps(content_block_stop)}\n\n".encode()
+                    )
+
         # 5. message_delta event (with final usage and stop_reason)
         # Include cache usage fields so clients that only read message_delta
         # (like Claude Code's SDK) see the full input token breakdown.