diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 5a36a4131..2045b8264 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.11.5"
+  ".": "0.11.6"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4088d956f..75bc4756f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,36 @@
 # Changelog
 
+## 0.11.6 (2026-05-29)
+
+Full Changelog: [v0.11.5...v0.11.6](https://github.com/scaleapi/scale-agentex-python/compare/v0.11.5...v0.11.6)
+
+### Features
+
+* **api:** add cleaned_at field to task response types ([38ed338](https://github.com/scaleapi/scale-agentex-python/commit/38ed3384094f7f07f6b2482489f457fd1dc4f76d))
+* **deps:** bump openai-agents to >=0.14.3 for scale-sandbox oai_agents adapter ([#375](https://github.com/scaleapi/scale-agentex-python/issues/375)) ([e1b31d9](https://github.com/scaleapi/scale-agentex-python/commit/e1b31d91abadec572989b805592b788500d61994))
+* **lib:** expose data_converter kwarg on AgentexWorker and Temporal client APIs ([#372](https://github.com/scaleapi/scale-agentex-python/issues/372)) ([d04624e](https://github.com/scaleapi/scale-agentex-python/commit/d04624e6899e43a0429ef2deeb84509265b9f636))
+
+
+### Bug Fixes
+
+* **tutorials:** restore tutorial CI deps after agentex-sdk 0.11.5 (pytest + debugpy) ([#379](https://github.com/scaleapi/scale-agentex-python/issues/379)) ([0a2418c](https://github.com/scaleapi/scale-agentex-python/commit/0a2418cc9f9b06e3bdc46099106e50d226412fa0))
+
+
+### Performance Improvements
+
+* **tracing:** span queue linger + per-loop httpx keepalive ([#362](https://github.com/scaleapi/scale-agentex-python/issues/362)) ([feec842](https://github.com/scaleapi/scale-agentex-python/commit/feec8426f79e9f02533451d44997717655fd33f2))
+
+
+### Chores
+
+* back-merge release 0.11.5 into next ([#381](https://github.com/scaleapi/scale-agentex-python/issues/381)) ([ab5a7d9](https://github.com/scaleapi/scale-agentex-python/commit/ab5a7d9732a56d47efad469675c7630046106ef6))
+* **deps:** drop unused runtime deps and exclude tests from wheel ([#367](https://github.com/scaleapi/scale-agentex-python/issues/367)) ([f4303d1](https://github.com/scaleapi/scale-agentex-python/commit/f4303d1e7211783d19beca6554e44eb73bb29c42))
+
+
+### Refactors
+
+* **types:** promote protocol types to agentex.protocol.* ([#371](https://github.com/scaleapi/scale-agentex-python/issues/371)) ([6f1c14f](https://github.com/scaleapi/scale-agentex-python/commit/6f1c14fd61077da52038361642a9fbc4a0a56c8b))
+
 ## 0.11.5 (2026-05-29)
 
 Full Changelog: [v0.11.4...v0.11.5](https://github.com/scaleapi/scale-agentex-python/compare/v0.11.4...v0.11.5)
diff --git a/examples/tutorials/run_agent_test.sh b/examples/tutorials/run_agent_test.sh
index d785ab088..c6fd17960 100755
--- a/examples/tutorials/run_agent_test.sh
+++ b/examples/tutorials/run_agent_test.sh
@@ -259,8 +259,15 @@ run_test() {
     cd "$tutorial_path" || return 1
 
 
-    # Run the tests with retry mechanism
-    local -a pytest_cmd=("uv" "run" "pytest")
+    # Run the tests with retry mechanism.
+    #
+    # pytest is brought in explicitly via --with: the tutorials only list it
+    # under an optional `dev` extra (which `uv run` does not install), and it
+    # used to be pulled in transitively by agentex-sdk's runtime deps. Once
+    # agentex-sdk 0.11.5 dropped pytest as a runtime dep, `uv run pytest` could
+    # no longer find it ("Failed to spawn: pytest"). Requesting it directly is
+    # robust across all tutorials regardless of how each declares test deps.
+    local -a pytest_cmd=("uv" "run" "--with" "pytest" "--with" "pytest-asyncio" "pytest")
     if [ "$BUILD_CLI" = true ]; then
         local wheel_file
         wheel_file=$(ls /home/runner/work/*/*/dist/agentex_sdk-*.whl 2>/dev/null | head -n1)
@@ -268,7 +275,7 @@ run_test() {
             wheel_file=$(ls "${SCRIPT_DIR}/../../dist/agentex_sdk-*.whl" 2>/dev/null | head -n1)
         fi
         if [[ -n "$wheel_file" ]]; then
-            pytest_cmd=("uv" "run" "--with" "$wheel_file" "pytest")
+            pytest_cmd=("uv" "run" "--with" "$wheel_file" "--with" "pytest" "--with" "pytest-asyncio" "pytest")
         fi
     fi
 
diff --git a/pyproject.toml b/pyproject.toml
index 7cf27ff4e..3d669f0dd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "agentex-sdk"
-version = "0.11.5"
+version = "0.11.6"
 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 6902d0b63..22dd4399f 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__ = "0.11.5"  # x-release-please-version
+__version__ = "0.11.6"  # x-release-please-version
diff --git a/src/agentex/lib/core/clients/temporal/temporal_client.py b/src/agentex/lib/core/clients/temporal/temporal_client.py
index f44648da2..ca17d30ff 100644
--- a/src/agentex/lib/core/clients/temporal/temporal_client.py
+++ b/src/agentex/lib/core/clients/temporal/temporal_client.py
@@ -7,7 +7,7 @@
 from temporalio.client import Client, WorkflowExecutionStatus
 from temporalio.common import RetryPolicy as TemporalRetryPolicy, WorkflowIDReusePolicy
 from temporalio.service import RPCError, RPCStatusCode
-from temporalio.converter import PayloadCodec
+from temporalio.converter import PayloadCodec, DataConverter
 
 from agentex.lib.utils.logging import make_logger
 from agentex.lib.utils.model_utils import BaseModel
@@ -78,11 +78,16 @@
 
 class TemporalClient:
     def __init__(
-        self, temporal_client: Client | None = None, plugins: list[Any] = [], payload_codec: PayloadCodec | None = None
+        self,
+        temporal_client: Client | None = None,
+        plugins: list[Any] = [],
+        payload_codec: PayloadCodec | None = None,
+        data_converter: DataConverter | None = None,
     ):
         self._client: Client | None = temporal_client
         self._plugins = plugins
         self._payload_codec = payload_codec
+        self._data_converter = data_converter
 
     @property
     def client(self) -> Client:
@@ -92,7 +97,13 @@ def client(self) -> Client:
         return self._client
 
     @classmethod
-    async def create(cls, temporal_address: str, plugins: list[Any] = [], payload_codec: PayloadCodec | None = None):
+    async def create(
+        cls,
+        temporal_address: str,
+        plugins: list[Any] = [],
+        payload_codec: PayloadCodec | None = None,
+        data_converter: DataConverter | None = None,
+    ):
         if temporal_address in [
             "false",
             "False",
@@ -105,8 +116,13 @@ async def create(cls, temporal_address: str, plugins: list[Any] = [], payload_co
         ]:
             _client = None
         else:
-            _client = await get_temporal_client(temporal_address, plugins=plugins, payload_codec=payload_codec)
-        return cls(_client, plugins, payload_codec)
+            _client = await get_temporal_client(
+                temporal_address,
+                plugins=plugins,
+                payload_codec=payload_codec,
+                data_converter=data_converter,
+            )
+        return cls(_client, plugins, payload_codec, data_converter)
 
     async def setup(self, temporal_address: str):
         self._client = await self._get_temporal_client(temporal_address=temporal_address)
@@ -124,7 +140,12 @@ async def _get_temporal_client(self, temporal_address: str) -> Client | None:
         ]:
             return None
         else:
-            return await get_temporal_client(temporal_address, plugins=self._plugins, payload_codec=self._payload_codec)
+            return await get_temporal_client(
+                temporal_address,
+                plugins=self._plugins,
+                payload_codec=self._payload_codec,
+                data_converter=self._data_converter,
+            )
 
     async def start_workflow(
         self,
diff --git a/src/agentex/lib/core/clients/temporal/utils.py b/src/agentex/lib/core/clients/temporal/utils.py
index 8c2241c62..95319720a 100644
--- a/src/agentex/lib/core/clients/temporal/utils.py
+++ b/src/agentex/lib/core/clients/temporal/utils.py
@@ -6,7 +6,7 @@
 from temporalio.client import Client, Plugin as ClientPlugin
 from temporalio.worker import Interceptor
 from temporalio.runtime import Runtime, TelemetryConfig, OpenTelemetryConfig
-from temporalio.converter import PayloadCodec
+from temporalio.converter import PayloadCodec, DataConverter
 from temporalio.contrib.pydantic import pydantic_data_converter
 
 # class DateTimeJSONEncoder(AdvancedJSONEncoder):
@@ -86,6 +86,7 @@ async def get_temporal_client(
     metrics_url: str | None = None,
     plugins: list[Any] = [],
     payload_codec: PayloadCodec | None = None,
+    data_converter: DataConverter | None = None,
 ) -> Client:
     """
     Create a Temporal client with plugin integration.
@@ -94,7 +95,14 @@ async def get_temporal_client(
         temporal_address: Temporal server address
         metrics_url: Optional metrics endpoint URL
         plugins: List of Temporal plugins to include
-        payload_codec: Optional payload codec for encoding/decoding payloads (e.g. encryption, compression)
+        payload_codec: Optional payload codec for encoding/decoding payloads
+            (e.g. encryption, compression). Cannot be combined with the
+            OpenAIAgentsPlugin via this kwarg — see ``data_converter``.
+        data_converter: Optional pre-built ``DataConverter``. Use this when
+            composing the OpenAIAgentsPlugin with a payload codec: build a
+            ``DataConverter(payload_converter_class=OpenAIPayloadConverter,
+            payload_codec=...)`` and pass it here. Mutually exclusive with
+            ``payload_codec``.
 
     Returns:
         Configured Temporal client
@@ -103,29 +111,40 @@ async def get_temporal_client(
     if plugins:
         validate_client_plugins(plugins)
 
-    # Check if OpenAI plugin is present - it needs to configure its own data converter
+    if payload_codec is not None and data_converter is not None:
+        raise ValueError(
+            "Pass payload_codec inside `data_converter` "
+            "(DataConverter(..., payload_codec=...)) instead of as a separate "
+            "kwarg. Specifying both is ambiguous."
+        )
+
     # 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 []))
 
-    if has_openai_plugin and payload_codec is not None:
+    if has_openai_plugin and payload_codec is not None and data_converter is None:
         raise ValueError(
-            "payload_codec is not supported alongside OpenAIAgentsPlugin: the plugin "
-            "installs its own data converter and the codec would be silently ignored, "
-            "leaving payloads unencoded. Remove one or the other."
+            "payload_codec passed as a kwarg alongside OpenAIAgentsPlugin would "
+            "be silently dropped by the plugin's data-converter transformer. "
+            "Build a DataConverter explicitly with "
+            "`payload_converter_class=OpenAIPayloadConverter` (or a subclass) "
+            "and `payload_codec=...`, then pass it via the `data_converter` "
+            "kwarg instead."
         )
 
-    connect_kwargs = {
+    connect_kwargs: dict[str, Any] = {
         "target_host": temporal_address,
         "plugins": plugins,
     }
 
-    if not has_openai_plugin:
-        data_converter = pydantic_data_converter
-        if payload_codec:
-            data_converter = dataclasses.replace(data_converter, payload_codec=payload_codec)
+    if data_converter is not None:
         connect_kwargs["data_converter"] = data_converter
+    elif not has_openai_plugin:
+        dc = pydantic_data_converter
+        if payload_codec:
+            dc = dataclasses.replace(dc, payload_codec=payload_codec)
+        connect_kwargs["data_converter"] = dc
 
     if not metrics_url:
         client = await Client.connect(**connect_kwargs)
diff --git a/src/agentex/lib/core/temporal/workers/worker.py b/src/agentex/lib/core/temporal/workers/worker.py
index 2e8591242..253b6759f 100644
--- a/src/agentex/lib/core/temporal/workers/worker.py
+++ b/src/agentex/lib/core/temporal/workers/worker.py
@@ -95,35 +95,45 @@ async def get_temporal_client(
     metrics_url: str | None = None,
     plugins: list = [],
     payload_codec: PayloadCodec | None = None,
+    data_converter: DataConverter | None = None,
 ) -> Client:
     if plugins != []:  # We don't need to validate the plugins if they are empty
         _validate_plugins(plugins)
 
-    # Check if OpenAI plugin is present - it needs to configure its own data converter
+    if payload_codec is not None and data_converter is not None:
+        raise ValueError(
+            "Pass payload_codec inside `data_converter` "
+            "(DataConverter(..., payload_codec=...)) instead of as a separate "
+            "kwarg. Specifying both is ambiguous."
+        )
+
     # 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 []))
 
-    if has_openai_plugin and payload_codec is not None:
+    if has_openai_plugin and payload_codec is not None and data_converter is None:
         raise ValueError(
-            "payload_codec is not supported alongside OpenAIAgentsPlugin: the plugin "
-            "installs its own data converter and the codec would be silently ignored, "
-            "leaving payloads unencoded. Remove one or the other."
+            "payload_codec passed as a kwarg alongside OpenAIAgentsPlugin would "
+            "be silently dropped by the plugin's data-converter transformer. "
+            "Build a DataConverter explicitly with "
+            "`payload_converter_class=OpenAIPayloadConverter` (or a subclass) "
+            "and `payload_codec=...`, then pass it via the `data_converter` "
+            "kwarg instead."
         )
 
-    # Build connection kwargs
-    connect_kwargs = {
+    connect_kwargs: dict[str, Any] = {
         "target_host": temporal_address,
         "plugins": plugins,
     }
 
-    # Only set data_converter if OpenAI plugin is not present
-    if not has_openai_plugin:
-        data_converter = custom_data_converter
-        if payload_codec:
-            data_converter = dataclasses.replace(data_converter, payload_codec=payload_codec)
+    if data_converter is not None:
         connect_kwargs["data_converter"] = data_converter
+    elif not has_openai_plugin:
+        dc = custom_data_converter
+        if payload_codec:
+            dc = dataclasses.replace(dc, payload_codec=payload_codec)
+        connect_kwargs["data_converter"] = dc
 
     if not metrics_url:
         client = await Client.connect(**connect_kwargs)
@@ -145,6 +155,7 @@ def __init__(
         interceptors: list = [],
         metrics_url: str | None = None,
         payload_codec: PayloadCodec | None = None,
+        data_converter: DataConverter | None = None,
     ):
         self.task_queue = task_queue
         self.activity_handles = []
@@ -159,6 +170,7 @@ def __init__(
         self.interceptors = interceptors
         self.metrics_url = metrics_url
         self.payload_codec = payload_codec
+        self.data_converter = data_converter
 
     @overload
     async def run(
@@ -195,6 +207,7 @@ async def run(
             plugins=self.plugins,
             metrics_url=self.metrics_url,
             payload_codec=self.payload_codec,
+            data_converter=self.data_converter,
         )
 
         # Enable debug mode if AgentEx debug is enabled (disables deadlock detection)
diff --git a/src/agentex/lib/sdk/fastacp/fastacp.py b/src/agentex/lib/sdk/fastacp/fastacp.py
index fbd4f0511..42859793d 100644
--- a/src/agentex/lib/sdk/fastacp/fastacp.py
+++ b/src/agentex/lib/sdk/fastacp/fastacp.py
@@ -65,6 +65,8 @@ def create_async_acp(config: AsyncACPConfig, **kwargs) -> BaseACPServer:
                 temporal_config["interceptors"] = config.interceptors  # type: ignore[attr-defined]
             if hasattr(config, "payload_codec"):
                 temporal_config["payload_codec"] = config.payload_codec  # type: ignore[attr-defined]
+            if hasattr(config, "data_converter"):
+                temporal_config["data_converter"] = config.data_converter  # type: ignore[attr-defined]
             return implementation_class.create(**temporal_config)
         else:
             return implementation_class.create(**kwargs)
diff --git a/src/agentex/lib/sdk/fastacp/impl/temporal_acp.py b/src/agentex/lib/sdk/fastacp/impl/temporal_acp.py
index 54fe72e6c..69d843720 100644
--- a/src/agentex/lib/sdk/fastacp/impl/temporal_acp.py
+++ b/src/agentex/lib/sdk/fastacp/impl/temporal_acp.py
@@ -4,7 +4,7 @@
 from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
-from temporalio.converter import PayloadCodec
+from temporalio.converter import PayloadCodec, DataConverter
 
 from agentex.protocol.acp import (
     SendEventParams,
@@ -33,6 +33,7 @@ def __init__(
         plugins: list[Any] | None = None,
         interceptors: list[Any] | None = None,
         payload_codec: PayloadCodec | None = None,
+        data_converter: DataConverter | None = None,
     ):
         super().__init__()
         self._temporal_task_service = temporal_task_service
@@ -40,6 +41,7 @@ def __init__(
         self._plugins = plugins or []
         self._interceptors = interceptors or []
         self._payload_codec = payload_codec
+        self._data_converter = data_converter
 
     @classmethod
     @override
@@ -49,12 +51,17 @@ def create(
         plugins: list[Any] | None = None,
         interceptors: list[Any] | None = None,
         payload_codec: PayloadCodec | None = None,
+        data_converter: DataConverter | None = None,
     ) -> "TemporalACP":
         logger.info("Initializing TemporalACP instance")
 
         # Create instance without temporal client initially
         temporal_acp = cls(
-            temporal_address=temporal_address, plugins=plugins, interceptors=interceptors, payload_codec=payload_codec
+            temporal_address=temporal_address,
+            plugins=plugins,
+            interceptors=interceptors,
+            payload_codec=payload_codec,
+            data_converter=data_converter,
         )
         temporal_acp._setup_handlers()
         logger.info("TemporalACP instance initialized now")
@@ -71,7 +78,10 @@ async def lifespan(app: FastAPI):
             if self._temporal_task_service is None:
                 env_vars = EnvironmentVariables.refresh()
                 temporal_client = await TemporalClient.create(
-                    temporal_address=self._temporal_address, plugins=self._plugins, payload_codec=self._payload_codec
+                    temporal_address=self._temporal_address,
+                    plugins=self._plugins,
+                    payload_codec=self._payload_codec,
+                    data_converter=self._data_converter,
                 )
                 self._temporal_task_service = TemporalTaskService(
                     temporal_client=temporal_client,
diff --git a/src/agentex/lib/types/fastacp.py b/src/agentex/lib/types/fastacp.py
index e11091e93..493ca5f11 100644
--- a/src/agentex/lib/types/fastacp.py
+++ b/src/agentex/lib/types/fastacp.py
@@ -2,7 +2,7 @@
 
 from typing import Any, Literal
 
-from pydantic import Field, BaseModel, field_validator
+from pydantic import Field, BaseModel, field_validator, model_validator
 
 from agentex.lib.core.clients.temporal.utils import validate_client_plugins, validate_worker_interceptors
 
@@ -56,7 +56,16 @@ class TemporalACPConfig(AsyncACPConfig):
             encoding/decoding payloads (e.g. encryption, compression). NOTE:
             this only configures the ACP (client) side. The worker side must
             be configured separately via ``AgentexWorker(payload_codec=...)``
-            with the SAME codec, or decode will fail at runtime.
+            with the SAME codec, or decode will fail at runtime. Cannot be
+            combined with ``OpenAIAgentsPlugin``; use ``data_converter``
+            instead in that case.
+        data_converter: Optional pre-built ``temporalio.converter.DataConverter``.
+            Use this when composing the ``OpenAIAgentsPlugin`` with a payload
+            codec: build a ``DataConverter(payload_converter_class=
+            OpenAIPayloadConverter, payload_codec=...)`` and pass it here.
+            Mutually exclusive with ``payload_codec``. The worker side must
+            be configured separately via ``AgentexWorker(data_converter=...)``
+            with the SAME converter, or decode will fail at runtime.
     """
 
     type: Literal["temporal"] = Field(default="temporal", frozen=True)
@@ -64,6 +73,7 @@ class TemporalACPConfig(AsyncACPConfig):
     plugins: list[Any] = Field(default=[], frozen=True)
     interceptors: list[Any] = Field(default=[], frozen=True)
     payload_codec: Any = Field(default=None, frozen=True)
+    data_converter: Any = Field(default=None, frozen=True)
 
     @field_validator("plugins")
     @classmethod
@@ -79,6 +89,16 @@ def validate_interceptors(cls, v: list[Any]) -> list[Any]:
         validate_worker_interceptors(v)
         return v
 
+    @model_validator(mode="after")
+    def _validate_codec_and_data_converter_mutually_exclusive(self) -> "TemporalACPConfig":
+        if self.payload_codec is not None and self.data_converter is not None:
+            raise ValueError(
+                "Pass payload_codec inside `data_converter` "
+                "(DataConverter(..., payload_codec=...)) instead of as a separate "
+                "field. Specifying both is ambiguous."
+            )
+        return self
+
 
 class AsyncBaseACPConfig(AsyncACPConfig):
     """Configuration for AsyncBaseACP implementation
diff --git a/src/agentex/lib/utils/debug.py b/src/agentex/lib/utils/debug.py
index 69cbf6b19..831199f9a 100644
--- a/src/agentex/lib/utils/debug.py
+++ b/src/agentex/lib/utils/debug.py
@@ -6,8 +6,6 @@
 
 import os
 
-import debugpy  # type: ignore
-
 from agentex.lib.utils.logging import make_logger
 
 logger = make_logger(__name__)
@@ -30,6 +28,13 @@ def setup_debug_if_enabled() -> None:
         Any exception from debugpy setup (will bubble up naturally)
     """
     if os.getenv("AGENTEX_DEBUG_ENABLED") == "true":
+        # Imported lazily: debugpy is a development-only tool, so a normal
+        # worker startup must not require it to be installed.  Importing it at
+        # module scope forced it onto every worker (it used to be satisfied
+        # transitively via ipykernel; that dep was dropped in agentex-sdk
+        # 0.11.5, surfacing this as "No module named 'debugpy'").
+        import debugpy  # type: ignore
+
         debug_port = int(os.getenv("AGENTEX_DEBUG_PORT", "5678"))
         debug_type = os.getenv("AGENTEX_DEBUG_TYPE", "worker")
         wait_for_attach = os.getenv("AGENTEX_DEBUG_WAIT_FOR_ATTACH", "false").lower() == "true"
diff --git a/tests/lib/test_payload_codec.py b/tests/lib/test_payload_codec.py
index bb2b24228..59736dc21 100644
--- a/tests/lib/test_payload_codec.py
+++ b/tests/lib/test_payload_codec.py
@@ -5,7 +5,11 @@
 
 import pytest
 from temporalio.client import Client, Plugin as ClientPlugin
-from temporalio.converter import PayloadCodec
+from temporalio.converter import (
+    PayloadCodec,
+    DataConverter,
+    DefaultPayloadConverter,
+)
 from temporalio.contrib.pydantic import pydantic_data_converter
 
 
@@ -68,6 +72,28 @@ async def test_create_propagates_codec_to_get_temporal_client(self):
         mock_get.assert_awaited_once()
         assert mock_get.await_args.kwargs["payload_codec"] is codec
 
+    def test_init_stores_data_converter(self):
+        from agentex.lib.core.clients.temporal.temporal_client import TemporalClient
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        client = TemporalClient(data_converter=dc)
+        assert client._data_converter is dc
+
+    def test_init_default_data_converter_is_none(self):
+        from agentex.lib.core.clients.temporal.temporal_client import TemporalClient
+
+        assert TemporalClient()._data_converter is None
+
+    async def test_create_propagates_data_converter_to_get_temporal_client(self):
+        import agentex.lib.core.clients.temporal.temporal_client as module
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        with patch.object(module, "get_temporal_client", new=AsyncMock(return_value=object())) as mock_get:
+            await module.TemporalClient.create(temporal_address="localhost:7233", plugins=[], data_converter=dc)
+
+        mock_get.assert_awaited_once()
+        assert mock_get.await_args.kwargs["data_converter"] is dc
+
 
 class TestGetTemporalClientUtils:
     async def test_no_codec_uses_pydantic_data_converter_unchanged(self):
@@ -96,7 +122,7 @@ async def test_codec_with_openai_plugin_raises(self):
 
         codec = _NoopCodec()
         with _patch_openai_plugin(), _mock_connect() as mock_connect:
-            with pytest.raises(ValueError, match="payload_codec is not supported alongside OpenAIAgentsPlugin"):
+            with pytest.raises(ValueError, match="silently dropped by the plugin's data-converter transformer"):
                 await get_temporal_client(
                     temporal_address="localhost:7233",
                     plugins=[_FakeOpenAIPlugin()],
@@ -112,6 +138,42 @@ async def test_openai_plugin_without_codec_omits_data_converter(self):
 
         assert "data_converter" not in mock_connect.await_args.kwargs
 
+    async def test_data_converter_passthrough_with_openai_plugin(self):
+        from agentex.lib.core.clients.temporal.utils import get_temporal_client
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        with _patch_openai_plugin(), _mock_connect() as mock_connect:
+            await get_temporal_client(
+                temporal_address="localhost:7233",
+                plugins=[_FakeOpenAIPlugin()],
+                data_converter=dc,
+            )
+
+        assert mock_connect.await_args.kwargs["data_converter"] is dc
+
+    async def test_data_converter_passthrough_without_openai_plugin(self):
+        from agentex.lib.core.clients.temporal.utils import get_temporal_client
+
+        dc = DataConverter(payload_converter_class=DefaultPayloadConverter)
+        with _mock_connect() as mock_connect:
+            await get_temporal_client(temporal_address="localhost:7233", data_converter=dc)
+
+        assert mock_connect.await_args.kwargs["data_converter"] is dc
+
+    async def test_codec_and_data_converter_together_raises(self):
+        from agentex.lib.core.clients.temporal.utils import get_temporal_client
+
+        codec = _NoopCodec()
+        dc = DataConverter(payload_codec=codec)
+        with _mock_connect() as mock_connect:
+            with pytest.raises(ValueError, match="Pass payload_codec inside `data_converter`"):
+                await get_temporal_client(
+                    temporal_address="localhost:7233",
+                    payload_codec=codec,
+                    data_converter=dc,
+                )
+            mock_connect.assert_not_awaited()
+
 
 class TestGetTemporalClientWorker:
     async def test_no_codec_uses_custom_data_converter_unchanged(self):
@@ -140,7 +202,7 @@ async def test_codec_with_openai_plugin_raises(self):
 
         codec = _NoopCodec()
         with _patch_openai_plugin(), _mock_connect() as mock_connect:
-            with pytest.raises(ValueError, match="payload_codec is not supported alongside OpenAIAgentsPlugin"):
+            with pytest.raises(ValueError, match="silently dropped by the plugin's data-converter transformer"):
                 await get_temporal_client(
                     temporal_address="localhost:7233",
                     plugins=[_FakeOpenAIPlugin()],
@@ -156,6 +218,42 @@ async def test_openai_plugin_without_codec_omits_data_converter(self):
 
         assert "data_converter" not in mock_connect.await_args.kwargs
 
+    async def test_data_converter_passthrough_with_openai_plugin(self):
+        from agentex.lib.core.temporal.workers.worker import get_temporal_client
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        with _patch_openai_plugin(), _mock_connect() as mock_connect:
+            await get_temporal_client(
+                temporal_address="localhost:7233",
+                plugins=[_FakeOpenAIPlugin()],
+                data_converter=dc,
+            )
+
+        assert mock_connect.await_args.kwargs["data_converter"] is dc
+
+    async def test_data_converter_passthrough_without_openai_plugin(self):
+        from agentex.lib.core.temporal.workers.worker import get_temporal_client
+
+        dc = DataConverter(payload_converter_class=DefaultPayloadConverter)
+        with _mock_connect() as mock_connect:
+            await get_temporal_client(temporal_address="localhost:7233", data_converter=dc)
+
+        assert mock_connect.await_args.kwargs["data_converter"] is dc
+
+    async def test_codec_and_data_converter_together_raises(self):
+        from agentex.lib.core.temporal.workers.worker import get_temporal_client
+
+        codec = _NoopCodec()
+        dc = DataConverter(payload_codec=codec)
+        with _mock_connect() as mock_connect:
+            with pytest.raises(ValueError, match="Pass payload_codec inside `data_converter`"):
+                await get_temporal_client(
+                    temporal_address="localhost:7233",
+                    payload_codec=codec,
+                    data_converter=dc,
+                )
+            mock_connect.assert_not_awaited()
+
 
 class TestAgentexWorkerCodec:
     def test_worker_stores_payload_codec(self):
@@ -171,6 +269,19 @@ def test_worker_default_payload_codec_is_none(self):
         worker = AgentexWorker(task_queue="test-queue", health_check_port=80)
         assert worker.payload_codec is None
 
+    def test_worker_stores_data_converter(self):
+        from agentex.lib.core.temporal.workers.worker import AgentexWorker
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        worker = AgentexWorker(task_queue="test-queue", health_check_port=80, data_converter=dc)
+        assert worker.data_converter is dc
+
+    def test_worker_default_data_converter_is_none(self):
+        from agentex.lib.core.temporal.workers.worker import AgentexWorker
+
+        worker = AgentexWorker(task_queue="test-queue", health_check_port=80)
+        assert worker.data_converter is None
+
 
 class TestTemporalACPCodec:
     def test_create_stores_payload_codec(self):
@@ -186,6 +297,19 @@ def test_create_default_payload_codec_is_none(self):
         acp = TemporalACP.create(temporal_address="localhost:7233")
         assert acp._payload_codec is None
 
+    def test_create_stores_data_converter(self):
+        from agentex.lib.sdk.fastacp.impl.temporal_acp import TemporalACP
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        acp = TemporalACP.create(temporal_address="localhost:7233", data_converter=dc)
+        assert acp._data_converter is dc
+
+    def test_create_default_data_converter_is_none(self):
+        from agentex.lib.sdk.fastacp.impl.temporal_acp import TemporalACP
+
+        acp = TemporalACP.create(temporal_address="localhost:7233")
+        assert acp._data_converter is None
+
 
 class TestFastACPConfigCodec:
     def test_config_default_codec_is_none(self):
@@ -218,3 +342,44 @@ def fake_create(**kwargs):
             FastACP.create("async", config=config)
 
         assert captured.get("payload_codec") is codec
+
+    def test_config_default_data_converter_is_none(self):
+        from agentex.lib.types.fastacp import TemporalACPConfig
+
+        assert TemporalACPConfig().data_converter is None
+
+    def test_config_accepts_data_converter(self):
+        from agentex.lib.types.fastacp import TemporalACPConfig
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        assert TemporalACPConfig(data_converter=dc).data_converter is dc
+
+    def test_config_rejects_codec_and_data_converter_together(self):
+        from pydantic import ValidationError
+
+        from agentex.lib.types.fastacp import TemporalACPConfig
+
+        codec = _NoopCodec()
+        dc = DataConverter(payload_codec=codec)
+        with pytest.raises(ValidationError, match="Pass payload_codec inside `data_converter`"):
+            TemporalACPConfig(payload_codec=codec, data_converter=dc)
+
+    def test_fastacp_forwards_data_converter_from_config(self):
+        from agentex.lib.types.fastacp import TemporalACPConfig
+        from agentex.lib.sdk.fastacp.fastacp import FastACP
+
+        dc = DataConverter(payload_codec=_NoopCodec())
+        config = TemporalACPConfig(data_converter=dc)
+        captured: dict[str, Any] = {}
+
+        def fake_create(**kwargs):
+            captured.update(kwargs)
+            return object()
+
+        with patch(
+            "agentex.lib.sdk.fastacp.impl.temporal_acp.TemporalACP.create",
+            side_effect=fake_create,
+        ):
+            FastACP.create("async", config=config)
+
+        assert captured.get("data_converter") is dc