diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index aaf968a1..b56c3d0b 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.1.0-alpha.3"
+  ".": "0.1.0-alpha.4"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0421fb5..5f014202 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.1.0-alpha.4 (2025-07-22)
+
+Full Changelog: [v0.1.0-alpha.3...v0.1.0-alpha.4](https://github.com/scaleapi/agentex-python/compare/v0.1.0-alpha.3...v0.1.0-alpha.4)
+
 ## 0.1.0-alpha.3 (2025-07-22)
 
 Full Changelog: [v0.1.0-alpha.2...v0.1.0-alpha.3](https://github.com/scaleapi/agentex-python/compare/v0.1.0-alpha.2...v0.1.0-alpha.3)
diff --git a/pyproject.toml b/pyproject.toml
index 487bd552..8e69b5ed 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "agentex"
-version = "0.1.0-alpha.3"
+version = "0.1.0-alpha.4"
 description = "The official Python library for the agentex API"
 dynamic = ["readme"]
 license = "Apache-2.0"
diff --git a/src/agentex/_version.py b/src/agentex/_version.py
index 90582396..756d68b8 100644
--- a/src/agentex/_version.py
+++ b/src/agentex/_version.py
@@ -1,4 +1,4 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 __title__ = "agentex"
-__version__ = "0.1.0-alpha.3"  # x-release-please-version
+__version__ = "0.1.0-alpha.4"  # x-release-please-version
diff --git a/src/agentex/lib/cli/templates/sync/project/acp.py.j2 b/src/agentex/lib/cli/templates/sync/project/acp.py.j2
index d990f5c5..ad6c935c 100644
--- a/src/agentex/lib/cli/templates/sync/project/acp.py.j2
+++ b/src/agentex/lib/cli/templates/sync/project/acp.py.j2
@@ -3,7 +3,8 @@ from agentex.lib.sdk.fastacp.fastacp import FastACP
 from agentex.lib.types.acp import SendMessageParams
 
 from agentex.lib.types.task_message_updates import TaskMessageUpdate
-from agentex.types.task_messages import TaskMessageContent, TextContent
+from agentex.types.task_message_content import TaskMessageContent
+from agentex.types.text_content import TextContent
 from agentex.lib.utils.logging import make_logger
 
 logger = make_logger(__name__)
@@ -14,14 +15,12 @@ acp = FastACP.create(
     acp_type="sync",
 )
 
-
 @acp.on_message_send
 async def handle_message_send(
     params: SendMessageParams
-) -> Union[TaskMessageContent, AsyncGenerator[TaskMessageUpdate, None]]:
+) -> TaskMessageContent | list[TaskMessageContent] | AsyncGenerator[TaskMessageUpdate, None]:
     """Default message handler with streaming support"""
     return TextContent(
         author="agent",
         content=f"Hello! I've received your message. Here's a generic response, but in future tutorials we'll see how you can get me to intelligently respond to your message. This is what I heard you say: {params.content.content}",
     )
-
diff --git a/src/agentex/lib/sdk/fastacp/base/base_acp_server.py b/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
index 746a1af0..843ef4d5 100644
--- a/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
+++ b/src/agentex/lib/sdk/fastacp/base/base_acp_server.py
@@ -294,7 +294,7 @@ def on_message_send(
         self,
         fn: Callable[
             [SendMessageParams],
-            Awaitable[list[TaskMessageContent] | AsyncGenerator[TaskMessageUpdate, None]],
+            Awaitable[TaskMessageContent | list[TaskMessageContent] | AsyncGenerator[TaskMessageUpdate, None]],
         ],
     ):
         """Handle message/send method - supports both single and streaming responses