diff --git a/src/google/adk/agents/agent_config.py b/src/google/adk/agents/agent_config.py
index 9e1e1d43..583048a6 100644
--- a/src/google/adk/agents/agent_config.py
+++ b/src/google/adk/agents/agent_config.py
@@ -20,7 +20,7 @@ from typing import Union
 from pydantic import Discriminator
 from pydantic import RootModel
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent import BaseAgentConfig
 from .llm_agent_config import LlmAgentConfig
 from .loop_agent_config import LoopAgentConfig
@@ -55,7 +55,7 @@ def agent_config_discriminator(v: Any):
 
 # Use a RootModel to represent the agent directly at the top level.
 # The `discriminator` is applied to the union within the RootModel.
-@working_in_progress("AgentConfig is not ready for use.")
+@experimental
 class AgentConfig(RootModel[ConfigsUnion]):
   """The config for the YAML schema to create an agent."""
 
diff --git a/src/google/adk/agents/base_agent.py b/src/google/adk/agents/base_agent.py
index 98f7b125..f26ee42d 100644
--- a/src/google/adk/agents/base_agent.py
+++ b/src/google/adk/agents/base_agent.py
@@ -39,7 +39,7 @@ from typing_extensions import override
 from typing_extensions import TypeAlias
 
 from ..events.event import Event
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent_config import BaseAgentConfig
 from .callback_context import CallbackContext
 from .common_configs import AgentRefConfig
@@ -506,6 +506,7 @@ class BaseAgent(BaseModel):
 
   @final
   @classmethod
+  @experimental
   def from_config(
       cls: Type[SelfAgent],
       config: BaseAgentConfig,
@@ -529,6 +530,7 @@ class BaseAgent(BaseModel):
     return cls(**kwargs)
 
   @classmethod
+  @experimental
   def _parse_config(
       cls: Type[SelfAgent],
       config: BaseAgentConfig,
diff --git a/src/google/adk/agents/base_agent_config.py b/src/google/adk/agents/base_agent_config.py
index aef9b03a..312584b8 100644
--- a/src/google/adk/agents/base_agent_config.py
+++ b/src/google/adk/agents/base_agent_config.py
@@ -14,46 +14,25 @@
 
 from __future__ import annotations
 
-import inspect
-from typing import Any
-from typing import AsyncGenerator
-from typing import Awaitable
-from typing import Callable
-from typing import Dict
-from typing import final
 from typing import List
 from typing import Literal
-from typing import Mapping
 from typing import Optional
 from typing import Type
 from typing import TYPE_CHECKING
 from typing import TypeVar
 from typing import Union
 
-from google.genai import types
-from opentelemetry import trace
 from pydantic import BaseModel
 from pydantic import ConfigDict
-from pydantic import Field
-from pydantic import field_validator
-from pydantic import model_validator
-from typing_extensions import override
-from typing_extensions import TypeAlias
 
-from ..events.event import Event
-from ..utils.feature_decorator import working_in_progress
-from .callback_context import CallbackContext
+from ..utils.feature_decorator import experimental
 from .common_configs import AgentRefConfig
 from .common_configs import CodeConfig
 
-if TYPE_CHECKING:
-  from .invocation_context import InvocationContext
-
-
 TBaseAgentConfig = TypeVar('TBaseAgentConfig', bound='BaseAgentConfig')
 
 
-@working_in_progress('BaseAgentConfig is not ready for use.')
+@experimental
 class BaseAgentConfig(BaseModel):
   """The config for the YAML schema of a BaseAgent.
 
diff --git a/src/google/adk/agents/common_configs.py b/src/google/adk/agents/common_configs.py
index 094b8fb7..b765fcb3 100644
--- a/src/google/adk/agents/common_configs.py
+++ b/src/google/adk/agents/common_configs.py
@@ -23,10 +23,10 @@ from pydantic import BaseModel
 from pydantic import ConfigDict
 from pydantic import model_validator
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 
 
-@working_in_progress("ArgumentConfig is not ready for use.")
+@experimental
 class ArgumentConfig(BaseModel):
   """An argument passed to a function or a class's constructor."""
 
@@ -42,7 +42,7 @@ class ArgumentConfig(BaseModel):
   """The argument value."""
 
 
-@working_in_progress("CodeConfig is not ready for use.")
+@experimental
 class CodeConfig(BaseModel):
   """Code reference config for a variable, a function, or a class.
 
@@ -80,6 +80,7 @@ class CodeConfig(BaseModel):
   """
 
 
+@experimental
 class AgentRefConfig(BaseModel):
   """The config for the reference to another agent."""
 
diff --git a/src/google/adk/agents/config_agent_utils.py b/src/google/adk/agents/config_agent_utils.py
index 80ea93b0..7982a9cf 100644
--- a/src/google/adk/agents/config_agent_utils.py
+++ b/src/google/adk/agents/config_agent_utils.py
@@ -22,7 +22,7 @@ from typing import List
 
 import yaml
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .agent_config import AgentConfig
 from .base_agent import BaseAgent
 from .base_agent_config import BaseAgentConfig
@@ -30,7 +30,7 @@ from .common_configs import AgentRefConfig
 from .common_configs import CodeConfig
 
 
-@working_in_progress("from_config is not ready for use.")
+@experimental
 def from_config(config_path: str) -> BaseAgent:
   """Build agent from a configfile path.
 
@@ -79,7 +79,6 @@ def _resolve_agent_class(agent_class: str) -> type[BaseAgent]:
   )
 
 
-@working_in_progress("_load_config_from_path is not ready for use.")
 def _load_config_from_path(config_path: str) -> AgentConfig:
   """Load an agent's configuration from a YAML file.
 
@@ -103,7 +102,7 @@ def _load_config_from_path(config_path: str) -> AgentConfig:
   return AgentConfig.model_validate(config_data)
 
 
-@working_in_progress("resolve_fully_qualified_name is not ready for use.")
+@experimental
 def resolve_fully_qualified_name(name: str) -> Any:
   try:
     module_path, obj_name = name.rsplit(".", 1)
@@ -113,7 +112,7 @@ def resolve_fully_qualified_name(name: str) -> Any:
     raise ValueError(f"Invalid fully qualified name: {name}") from e
 
 
-@working_in_progress("resolve_agent_reference is not ready for use.")
+@experimental
 def resolve_agent_reference(
     ref_config: AgentRefConfig, referencing_agent_config_abs_path: str
 ) -> BaseAgent:
@@ -143,7 +142,6 @@ def resolve_agent_reference(
     raise ValueError("AgentRefConfig must have either 'code' or 'config_path'")
 
 
-@working_in_progress("_resolve_agent_code_reference is not ready for use.")
 def _resolve_agent_code_reference(code: str) -> Any:
   """Resolve a code reference to an actual agent instance.
 
@@ -172,7 +170,7 @@ def _resolve_agent_code_reference(code: str) -> Any:
   return obj
 
 
-@working_in_progress("resolve_code_reference is not ready for use.")
+@experimental
 def resolve_code_reference(code_config: CodeConfig) -> Any:
   """Resolve a code reference to actual Python object.
 
@@ -201,7 +199,7 @@ def resolve_code_reference(code_config: CodeConfig) -> Any:
     return obj
 
 
-@working_in_progress("resolve_callbacks is not ready for use.")
+@experimental
 def resolve_callbacks(callbacks_config: List[CodeConfig]) -> Any:
   """Resolve callbacks from configuration.
 
diff --git a/src/google/adk/agents/llm_agent.py b/src/google/adk/agents/llm_agent.py
index 8ebcade5..7f753521 100644
--- a/src/google/adk/agents/llm_agent.py
+++ b/src/google/adk/agents/llm_agent.py
@@ -51,7 +51,7 @@ from ..tools.base_toolset import BaseToolset
 from ..tools.function_tool import FunctionTool
 from ..tools.tool_configs import ToolConfig
 from ..tools.tool_context import ToolContext
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent import BaseAgent
 from .base_agent_config import BaseAgentConfig
 from .callback_context import CallbackContext
@@ -521,7 +521,7 @@ class LlmAgent(BaseAgent):
     return generate_content_config
 
   @classmethod
-  @working_in_progress('LlmAgent._resolve_tools is not ready for use.')
+  @experimental
   def _resolve_tools(
       cls, tool_configs: list[ToolConfig], config_abs_path: str
   ) -> list[Any]:
@@ -580,6 +580,7 @@ class LlmAgent(BaseAgent):
 
   @override
   @classmethod
+  @experimental
   def _parse_config(
       cls: Type[LlmAgent],
       config: LlmAgentConfig,
diff --git a/src/google/adk/agents/loop_agent.py b/src/google/adk/agents/loop_agent.py
index de4f3438..da879f7d 100644
--- a/src/google/adk/agents/loop_agent.py
+++ b/src/google/adk/agents/loop_agent.py
@@ -27,7 +27,7 @@ from typing_extensions import override
 
 from ..agents.invocation_context import InvocationContext
 from ..events.event import Event
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent import BaseAgent
 from .base_agent_config import BaseAgentConfig
 from .loop_agent_config import LoopAgentConfig
@@ -78,6 +78,7 @@ class LoopAgent(BaseAgent):
 
   @override
   @classmethod
+  @experimental
   def _parse_config(
       cls: type[LoopAgent],
       config: LoopAgentConfig,
diff --git a/src/google/adk/agents/loop_agent_config.py b/src/google/adk/agents/loop_agent_config.py
index c50785c7..c11af1b2 100644
--- a/src/google/adk/agents/loop_agent_config.py
+++ b/src/google/adk/agents/loop_agent_config.py
@@ -21,11 +21,11 @@ from typing import Optional
 
 from pydantic import ConfigDict
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent_config import BaseAgentConfig
 
 
-@working_in_progress('LoopAgentConfig is not ready for use.')
+@experimental
 class LoopAgentConfig(BaseAgentConfig):
   """The config for the YAML schema of a LoopAgent."""
 
diff --git a/src/google/adk/agents/parallel_agent.py b/src/google/adk/agents/parallel_agent.py
index bb8e0a46..ffc29a09 100644
--- a/src/google/adk/agents/parallel_agent.py
+++ b/src/google/adk/agents/parallel_agent.py
@@ -26,7 +26,6 @@ from typing import Type
 from typing_extensions import override
 
 from ..events.event import Event
-from ..utils.feature_decorator import working_in_progress
 from .base_agent import BaseAgent
 from .base_agent_config import BaseAgentConfig
 from .invocation_context import InvocationContext
diff --git a/src/google/adk/agents/parallel_agent_config.py b/src/google/adk/agents/parallel_agent_config.py
index ce6a936e..9989ae5c 100644
--- a/src/google/adk/agents/parallel_agent_config.py
+++ b/src/google/adk/agents/parallel_agent_config.py
@@ -20,11 +20,11 @@ from typing import Literal
 
 from pydantic import ConfigDict
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 from .base_agent_config import BaseAgentConfig
 
 
-@working_in_progress('ParallelAgentConfig is not ready for use.')
+@experimental
 class ParallelAgentConfig(BaseAgentConfig):
   """The config for the YAML schema of a ParallelAgent."""
 
diff --git a/src/google/adk/agents/sequential_agent.py b/src/google/adk/agents/sequential_agent.py
index 10d1e7c2..6ed203ed 100644
--- a/src/google/adk/agents/sequential_agent.py
+++ b/src/google/adk/agents/sequential_agent.py
@@ -22,7 +22,6 @@ from typing import Type
 from typing_extensions import override
 
 from ..events.event import Event
-from ..utils.feature_decorator import working_in_progress
 from .base_agent import BaseAgent
 from .base_agent import BaseAgentConfig
 from .invocation_context import InvocationContext
diff --git a/src/google/adk/agents/sequential_agent_config.py b/src/google/adk/agents/sequential_agent_config.py
index d8660aea..e454ed87 100644
--- a/src/google/adk/agents/sequential_agent_config.py
+++ b/src/google/adk/agents/sequential_agent_config.py
@@ -20,11 +20,11 @@ from typing import Literal
 
 from pydantic import ConfigDict
 
-from ..agents.base_agent import working_in_progress
+from ..agents.base_agent import experimental
 from ..agents.base_agent_config import BaseAgentConfig
 
 
-@working_in_progress('SequentialAgentConfig is not ready for use.')
+@experimental
 class SequentialAgentConfig(BaseAgentConfig):
   """The config for the YAML schema of a SequentialAgent."""
 
diff --git a/src/google/adk/cli/utils/agent_loader.py b/src/google/adk/cli/utils/agent_loader.py
index 0bc44abd..c5c83e4d 100644
--- a/src/google/adk/cli/utils/agent_loader.py
+++ b/src/google/adk/cli/utils/agent_loader.py
@@ -27,7 +27,7 @@ from typing_extensions import override
 from . import envs
 from ...agents import config_agent_utils
 from ...agents.base_agent import BaseAgent
-from ...utils.feature_decorator import working_in_progress
+from ...utils.feature_decorator import experimental
 from .base_agent_loader import BaseAgentLoader
 
 logger = logging.getLogger("google_adk." + __name__)
@@ -138,7 +138,7 @@ class AgentLoader(BaseAgentLoader):
 
     return None
 
-  @working_in_progress("_load_from_yaml_config is not ready for use.")
+  @experimental
   def _load_from_yaml_config(self, agent_name: str) -> Optional[BaseAgent]:
     # Load from the config file at agents_dir/{agent_name}/root_agent.yaml
     config_path = os.path.join(self.agents_dir, agent_name, "root_agent.yaml")
@@ -178,9 +178,7 @@ class AgentLoader(BaseAgentLoader):
     if root_agent := self._load_from_submodule(agent_name):
       return root_agent
 
-    if os.getenv("ADK_ALLOW_WIP_FEATURES") and (
-        root_agent := self._load_from_yaml_config(agent_name)
-    ):
+    if root_agent := self._load_from_yaml_config(agent_name):
       return root_agent
 
     # If no root_agent was found by any pattern
diff --git a/src/google/adk/plugins/base_plugin.py b/src/google/adk/plugins/base_plugin.py
index 08e281db..c35c08f6 100644
--- a/src/google/adk/plugins/base_plugin.py
+++ b/src/google/adk/plugins/base_plugin.py
@@ -28,7 +28,6 @@ from ..events.event import Event
 from ..models.llm_request import LlmRequest
 from ..models.llm_response import LlmResponse
 from ..tools.base_tool import BaseTool
-from ..utils.feature_decorator import working_in_progress
 
 if TYPE_CHECKING:
   from ..agents.invocation_context import InvocationContext
diff --git a/src/google/adk/tools/tool_configs.py b/src/google/adk/tools/tool_configs.py
index a1b82077..9210e646 100644
--- a/src/google/adk/tools/tool_configs.py
+++ b/src/google/adk/tools/tool_configs.py
@@ -19,10 +19,10 @@ from typing import Optional
 from pydantic import BaseModel
 from pydantic import ConfigDict
 
-from ..utils.feature_decorator import working_in_progress
+from ..utils.feature_decorator import experimental
 
 
-@working_in_progress("BaseToolConfig is not ready for use.")
+@experimental
 class BaseToolConfig(BaseModel):
   """The base class for all tool configs."""
 
@@ -30,14 +30,14 @@ class BaseToolConfig(BaseModel):
   """Forbid extra fields."""
 
 
-@working_in_progress("ToolArgsConfig is not ready for use.")
+@experimental
 class ToolArgsConfig(BaseModel):
   """Config to host free key-value pairs for the args in ToolConfig."""
 
   model_config = ConfigDict(extra="allow")
 
 
-@working_in_progress("ToolConfig is not ready for use.")
+@experimental
 class ToolConfig(BaseModel):
   """The configuration for a tool.
 
diff --git a/tests/unittests/cli/utils/test_agent_loader.py b/tests/unittests/cli/utils/test_agent_loader.py
index 81d6baae..a17d6edd 100644
--- a/tests/unittests/cli/utils/test_agent_loader.py
+++ b/tests/unittests/cli/utils/test_agent_loader.py
@@ -31,8 +31,6 @@ class TestAgentLoader:
     """Ensure sys.path is restored after each test."""
     original_path = sys.path.copy()
     original_env = os.environ.copy()
-    # Enable WIP features for YAML agent loading tests
-    os.environ["ADK_ALLOW_WIP_FEATURES"] = "true"
     yield
     sys.path[:] = original_path
     # Restore environment variables