Fix tutorial test failures across sync and temporal agents

- worker.py: Remove private _JSONTypeConverterUnhandled import (removed
  in newer temporalio) and lazy-import OpenAIAgentsPlugin to avoid
  opentelemetry.sdk dependency at import time. Fixes all 10 temporal
  tutorial tests.
- 020_streaming/acp.py: Fix TextContent import path and add missing
  return after error yield.
- 030_langgraph/graph.py: Change model from gpt-5 (invalid) to
  gpt-4o-mini, remove unsupported reasoning parameter.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: danielmillerp

examples/tutorials/00_sync/020_streaming/project/acp.py

@@ -9,7 +9,8 @@
 from agentex.lib.utils.model_utils import BaseModel
 from agentex.lib.sdk.fastacp.fastacp import FastACP
 from agentex.types.task_message_update import TaskMessageUpdate, StreamTaskMessageFull
-from agentex.types.task_message_content import TextContent, TaskMessageContent
+from agentex.types.task_message_content import TaskMessageContent
+from agentex.types.text_content import TextContent
 from agentex.lib.adk.providers._modules.sync_provider import (
     SyncStreamingProvider,
     convert_openai_to_agentex_events,
@@ -56,6 +57,7 @@ async def handle_message_send(
                 content="Hey, sorry I'm unable to respond to your message because you're running this example without an OpenAI API key. Please set the OPENAI_API_KEY environment variable to run this example. Do this by either by adding a .env file to the project/ directory or by setting the environment variable in your terminal.",
             ),
         )
+        return
 
     # Try to retrieve the state. If it doesn't exist, create it.
     task_state = await adk.state.get_by_task_and_agent(task_id=params.task.id, agent_id=params.agent.id)

examples/tutorials/00_sync/030_langgraph/project/graph.py

@@ -20,7 +20,7 @@
 from project.tools import TOOLS
 from agentex.lib.adk import create_checkpointer
 
-MODEL_NAME = "gpt-5"
+MODEL_NAME = "gpt-4o-mini"
 SYSTEM_PROMPT = """You are a helpful AI assistant with access to tools.
 
 Current date and time: {timestamp}
@@ -46,7 +46,6 @@ async def create_graph():
     """
     llm = ChatOpenAI(
         model=MODEL_NAME,
-        reasoning={"effort": "high", "summary": "auto"},
     )
     llm_with_tools = llm.bind_tools(TOOLS)
 

src/agentex/lib/core/temporal/workers/worker.py

@@ -24,9 +24,7 @@
     DefaultPayloadConverter,
     CompositePayloadConverter,
     JSONPlainPayloadConverter,
-    _JSONTypeConverterUnhandled,
 )
-from temporalio.contrib.openai_agents import OpenAIAgentsPlugin
 
 from agentex.lib.utils.logging import make_logger
 from agentex.lib.utils.registration import register_agent
@@ -45,7 +43,7 @@ def default(self, o: Any) -> Any:
 
 class DateTimeJSONTypeConverter(JSONTypeConverter):
     @override
-    def to_typed_value(self, hint: type, value: Any) -> Any | None | _JSONTypeConverterUnhandled:
+    def to_typed_value(self, hint: type, value: Any) -> Any | None:
         if hint == datetime.datetime:
             return datetime.datetime.fromisoformat(value)
         return JSONTypeConverter.Unhandled
@@ -96,6 +94,8 @@ async def get_temporal_client(temporal_address: str, metrics_url: str | None = N
         _validate_plugins(plugins)
 
     # Check if OpenAI plugin is present - it needs to configure its own data converter
+    # Lazy import to avoid pulling in opentelemetry.sdk for non-Temporal agents
+    from temporalio.contrib.openai_agents import OpenAIAgentsPlugin
     has_openai_plugin = any(
         isinstance(p, OpenAIAgentsPlugin) for p in (plugins or [])
     )