diff --git a/engine/data_sources/pipeline_introspection.py b/engine/data_sources/pipeline_introspection.py
index b7c372d..31c67fd 100644
--- a/engine/data_sources/pipeline_introspection.py
+++ b/engine/data_sources/pipeline_introspection.py
@@ -67,13 +67,13 @@ class PipelineIntrospectionSource(DataSource):
 
     @property
     def inlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.NONE}
 
     @property
     def outlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.SOURCE_ITEMS}
 
diff --git a/engine/effects/plugins/tint.py b/engine/effects/plugins/tint.py
index ce8c941..b983f77 100644
--- a/engine/effects/plugins/tint.py
+++ b/engine/effects/plugins/tint.py
@@ -20,13 +20,13 @@ class TintEffect(EffectPlugin):
     # Define inlet types for PureData-style typing
     @property
     def inlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.TEXT_BUFFER}
 
     @property
     def outlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.TEXT_BUFFER}
 
diff --git a/engine/interfaces/__init__.py b/engine/interfaces/__init__.py
index 2d8879f..8d5d899 100644
--- a/engine/interfaces/__init__.py
+++ b/engine/interfaces/__init__.py
@@ -28,7 +28,7 @@ from engine.effects.types import (
     apply_param_bindings,
     create_effect_context,
 )
-from engine.pipeline.core import (
+from engine.pipeline import (
     DataType,
     Stage,
     StageConfig,
diff --git a/engine/pipeline/__init__.py b/engine/pipeline/__init__.py
index ff740d0..22b4a81 100644
--- a/engine/pipeline/__init__.py
+++ b/engine/pipeline/__init__.py
@@ -26,6 +26,11 @@ from sideline.pipeline import (
     register_source,
 )
 
+# Also re-export from sideline.core for compatibility
+from sideline.pipeline.core import (
+    DataType,
+)
+
 # Re-export from engine.pipeline.presets (Mainline-specific)
 from engine.pipeline.presets import (
     DEMO_PRESET,
@@ -91,4 +96,6 @@ __all__ = [
     "register_effect",
     "register_display",
     "register_camera",
+    # Core types (from sideline)
+    "DataType",
 ]
diff --git a/engine/pipeline/adapters/camera.py b/engine/pipeline/adapters/camera.py
index d0fca41..17a7f3d 100644
--- a/engine/pipeline/adapters/camera.py
+++ b/engine/pipeline/adapters/camera.py
@@ -3,7 +3,7 @@
 import time
 from typing import Any
 
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 
 
 class CameraClockStage(Stage):
diff --git a/engine/pipeline/adapters/data_source.py b/engine/pipeline/adapters/data_source.py
index 04a59af..ecdfc9e 100644
--- a/engine/pipeline/adapters/data_source.py
+++ b/engine/pipeline/adapters/data_source.py
@@ -8,7 +8,7 @@ This module provides adapters that wrap existing components
 from typing import Any
 
 from engine.data_sources import SourceItem
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 
 
 class DataSourceStage(Stage):
diff --git a/engine/pipeline/adapters/display.py b/engine/pipeline/adapters/display.py
index cdef260..f04b3e0 100644
--- a/engine/pipeline/adapters/display.py
+++ b/engine/pipeline/adapters/display.py
@@ -2,7 +2,7 @@
 
 from typing import Any
 
-from engine.pipeline.core import PipelineContext, Stage
+from engine.pipeline import PipelineContext, Stage
 
 
 class DisplayStage(Stage):
@@ -59,13 +59,13 @@ class DisplayStage(Stage):
 
     @property
     def inlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.TEXT_BUFFER}  # Display consumes rendered text
 
     @property
     def outlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.NONE}  # Display is a terminal stage (no output)
 
diff --git a/engine/pipeline/adapters/effect_plugin.py b/engine/pipeline/adapters/effect_plugin.py
index 1185021..6b038e7 100644
--- a/engine/pipeline/adapters/effect_plugin.py
+++ b/engine/pipeline/adapters/effect_plugin.py
@@ -2,7 +2,7 @@
 
 from typing import Any
 
-from engine.pipeline.core import PipelineContext, Stage
+from engine.pipeline import PipelineContext, Stage
 
 
 class EffectPluginStage(Stage):
@@ -69,13 +69,13 @@ class EffectPluginStage(Stage):
 
     @property
     def inlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.TEXT_BUFFER}
 
     @property
     def outlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.TEXT_BUFFER}
 
diff --git a/engine/pipeline/adapters/frame_capture.py b/engine/pipeline/adapters/frame_capture.py
index 03d909a..5fda41b 100644
--- a/engine/pipeline/adapters/frame_capture.py
+++ b/engine/pipeline/adapters/frame_capture.py
@@ -7,7 +7,7 @@ Wraps pipeline stages to capture frames for animation report generation.
 from typing import Any
 
 from engine.display.backends.animation_report import AnimationReportDisplay
-from engine.pipeline.core import PipelineContext, Stage
+from engine.pipeline import PipelineContext, Stage
 
 
 class FrameCaptureStage(Stage):
diff --git a/engine/pipeline/adapters/message_overlay.py b/engine/pipeline/adapters/message_overlay.py
index 2433a38..140e533 100644
--- a/engine/pipeline/adapters/message_overlay.py
+++ b/engine/pipeline/adapters/message_overlay.py
@@ -12,7 +12,7 @@ from datetime import datetime
 
 from engine import config
 from engine.effects.legacy import vis_trunc
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 from engine.render.blocks import big_wrap
 from engine.render.gradient import msg_gradient
 
diff --git a/engine/pipeline/adapters/positioning.py b/engine/pipeline/adapters/positioning.py
index 40d48ec..35c410d 100644
--- a/engine/pipeline/adapters/positioning.py
+++ b/engine/pipeline/adapters/positioning.py
@@ -10,7 +10,7 @@ different ANSI positioning approaches:
 from enum import Enum
 from typing import Any
 
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 
 
 class PositioningMode(Enum):
diff --git a/engine/pipeline/adapters/transform.py b/engine/pipeline/adapters/transform.py
index e1b6c08..7bab5e8 100644
--- a/engine/pipeline/adapters/transform.py
+++ b/engine/pipeline/adapters/transform.py
@@ -4,7 +4,7 @@ from typing import Any
 
 import engine.render
 from engine.data_sources import SourceItem
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 
 
 def estimate_simple_height(text: str, width: int) -> int:
diff --git a/engine/pipeline/controller.py b/engine/pipeline/controller.py
index 62eeb49..c3b087d 100644
--- a/engine/pipeline/controller.py
+++ b/engine/pipeline/controller.py
@@ -9,7 +9,7 @@ import time
 from dataclasses import dataclass, field
 from typing import Any
 
-from engine.pipeline.core import PipelineContext, Stage, StageError, StageResult
+from engine.pipeline import PipelineContext, Stage, StageError, StageResult
 from engine.pipeline.params import PipelineParams
 from engine.pipeline.registry import StageRegistry
 
@@ -640,7 +640,7 @@ class Pipeline:
 
         Raises StageError if type mismatch is detected.
         """
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         errors: list[str] = []
 
diff --git a/engine/pipeline/core.py b/engine/pipeline/core.py
deleted file mode 100644
index 55ebf8c..0000000
--- a/engine/pipeline/core.py
+++ /dev/null
@@ -1,321 +0,0 @@
-"""
-Pipeline core - Unified Stage abstraction and PipelineContext.
-
-This module provides the foundation for a clean, dependency-managed pipeline:
-- Stage: Base class for all pipeline components (sources, effects, displays, cameras)
-- PipelineContext: Dependency injection context for runtime data exchange
-- Capability system: Explicit capability declarations with duck-typing support
-- DataType: PureData-style inlet/outlet typing for validation
-"""
-
-from abc import ABC, abstractmethod
-from collections.abc import Callable
-from dataclasses import dataclass, field
-from enum import Enum, auto
-from typing import TYPE_CHECKING, Any
-
-if TYPE_CHECKING:
-    from engine.pipeline.params import PipelineParams
-
-
-class DataType(Enum):
-    """PureData-style data types for inlet/outlet validation.
-
-    Each type represents a specific data format that flows through the pipeline.
-    This enables compile-time-like validation of connections.
-
-    Examples:
-        SOURCE_ITEMS: List[SourceItem] - raw items from sources
-        ITEM_TUPLES: List[tuple] - (title, source, timestamp) tuples
-        TEXT_BUFFER: List[str] - rendered ANSI buffer for display
-        RAW_TEXT: str - raw text strings
-        PIL_IMAGE: PIL Image object
-    """
-
-    SOURCE_ITEMS = auto()  # List[SourceItem] - from DataSource
-    ITEM_TUPLES = auto()  # List[tuple] - (title, source, ts)
-    TEXT_BUFFER = auto()  # List[str] - ANSI buffer
-    RAW_TEXT = auto()  # str - raw text
-    PIL_IMAGE = auto()  # PIL Image object
-    ANY = auto()  # Accepts any type
-    NONE = auto()  # No data (terminator)
-
-
-@dataclass
-class StageConfig:
-    """Configuration for a single stage."""
-
-    name: str
-    category: str
-    enabled: bool = True
-    optional: bool = False
-    params: dict[str, Any] = field(default_factory=dict)
-
-
-class Stage(ABC):
-    """Abstract base class for all pipeline stages.
-
-    A Stage is a single component in the rendering pipeline. Stages can be:
-    - Sources: Data providers (headlines, poetry, pipeline viz)
-    - Effects: Post-processors (noise, fade, glitch, hud)
-    - Displays: Output backends (terminal, pygame, websocket)
-    - Cameras: Viewport controllers (vertical, horizontal, omni)
-    - Overlays: UI elements that compose on top (HUD)
-
-    Stages declare:
-    - capabilities: What they provide to other stages
-    - dependencies: What they need from other stages
-    - stage_type: Category of stage (source, effect, overlay, display)
-    - render_order: Execution order within category
-    - is_overlay: If True, output is composited on top, not passed downstream
-
-    Duck-typing is supported: any class with the required methods can act as a Stage.
-    """
-
-    name: str
-    category: str  # "source", "effect", "overlay", "display", "camera"
-    optional: bool = False  # If True, pipeline continues even if stage fails
-
-    @property
-    def stage_type(self) -> str:
-        """Category of stage for ordering.
-
-        Valid values: "source", "effect", "overlay", "display", "camera"
-        Defaults to category for backwards compatibility.
-        """
-        return self.category
-
-    @property
-    def render_order(self) -> int:
-        """Execution order within stage_type group.
-
-        Higher values execute later. Useful for ordering overlays
-        or effects that need specific execution order.
-        """
-        return 0
-
-    @property
-    def is_overlay(self) -> bool:
-        """If True, this stage's output is composited on top of the buffer.
-
-        Overlay stages don't pass their output to the next stage.
-        Instead, their output is layered on top of the final buffer.
-        Use this for HUD, status displays, and similar UI elements.
-        """
-        return False
-
-    @property
-    def inlet_types(self) -> set[DataType]:
-        """Return set of data types this stage accepts.
-
-        PureData-style inlet typing. If the connected upstream stage's
-        outlet_type is not in this set, the pipeline will raise an error.
-
-        Examples:
-            - Source stages: {DataType.NONE} (no input needed)
-            - Transform stages: {DataType.ITEM_TUPLES, DataType.TEXT_BUFFER}
-            - Display stages: {DataType.TEXT_BUFFER}
-        """
-        return {DataType.ANY}
-
-    @property
-    def outlet_types(self) -> set[DataType]:
-        """Return set of data types this stage produces.
-
-        PureData-style outlet typing. Downstream stages must accept
-        this type in their inlet_types.
-
-        Examples:
-            - Source stages: {DataType.SOURCE_ITEMS}
-            - Transform stages: {DataType.TEXT_BUFFER}
-            - Display stages: {DataType.NONE} (consumes data)
-        """
-        return {DataType.ANY}
-
-    @property
-    def capabilities(self) -> set[str]:
-        """Return set of capabilities this stage provides.
-
-        Examples:
-            - "source.headlines"
-            - "effect.noise"
-            - "display.output"
-            - "camera"
-        """
-        return {f"{self.category}.{self.name}"}
-
-    @property
-    def dependencies(self) -> set[str]:
-        """Return set of capability names this stage needs.
-
-        Examples:
-            - {"display.output"}
-            - {"source.headlines"}
-            - {"camera"}
-        """
-        return set()
-
-    @property
-    def stage_dependencies(self) -> set[str]:
-        """Return set of stage names this stage must connect to directly.
-
-        This allows explicit stage-to-stage dependencies, useful for enforcing
-        pipeline structure when capability matching alone is insufficient.
-
-        Examples:
-            - {"viewport_filter"}  # Must connect to viewport_filter stage
-            - {"camera_update"}    # Must connect to camera_update stage
-
-        NOTE: These are stage names (as added to pipeline), not capabilities.
-        """
-        return set()
-
-    def init(self, ctx: "PipelineContext") -> bool:
-        """Initialize stage with pipeline context.
-
-        Args:
-            ctx: PipelineContext for accessing services
-
-        Returns:
-            True if initialization succeeded, False otherwise
-        """
-        return True
-
-    @abstractmethod
-    def process(self, data: Any, ctx: "PipelineContext") -> Any:
-        """Process input data and return output.
-
-        Args:
-            data: Input data from previous stage (or initial data for first stage)
-            ctx: PipelineContext for accessing services and state
-
-        Returns:
-            Processed data for next stage
-        """
-        ...
-
-    def cleanup(self) -> None:  # noqa: B027
-        """Clean up resources when pipeline shuts down."""
-        pass
-
-    def get_config(self) -> StageConfig:
-        """Return current configuration of this stage."""
-        return StageConfig(
-            name=self.name,
-            category=self.category,
-            optional=self.optional,
-        )
-
-    def set_enabled(self, enabled: bool) -> None:
-        """Enable or disable this stage."""
-        self._enabled = enabled  # type: ignore[attr-defined]
-
-    def is_enabled(self) -> bool:
-        """Check if stage is enabled."""
-        return getattr(self, "_enabled", True)
-
-
-@dataclass
-class StageResult:
-    """Result of stage processing, including success/failure info."""
-
-    success: bool
-    data: Any
-    error: str | None = None
-    stage_name: str = ""
-
-
-class PipelineContext:
-    """Dependency injection context passed through the pipeline.
-
-    Provides:
-    - services: Named services (display, config, event_bus, etc.)
-    - state: Runtime state shared between stages
-    - params: PipelineParams for animation-driven config
-
-    Services can be injected at construction time or lazily resolved.
-    """
-
-    def __init__(
-        self,
-        services: dict[str, Any] | None = None,
-        initial_state: dict[str, Any] | None = None,
-    ):
-        self.services: dict[str, Any] = services or {}
-        self.state: dict[str, Any] = initial_state or {}
-        self._params: PipelineParams | None = None
-
-        # Lazy resolvers for common services
-        self._lazy_resolvers: dict[str, Callable[[], Any]] = {
-            "config": self._resolve_config,
-            "event_bus": self._resolve_event_bus,
-        }
-
-    def _resolve_config(self) -> Any:
-        from engine.config import get_config
-
-        return get_config()
-
-    def _resolve_event_bus(self) -> Any:
-        from engine.eventbus import get_event_bus
-
-        return get_event_bus()
-
-    def get(self, key: str, default: Any = None) -> Any:
-        """Get a service or state value by key.
-
-        First checks services, then state, then lazy resolution.
-        """
-        if key in self.services:
-            return self.services[key]
-        if key in self.state:
-            return self.state[key]
-        if key in self._lazy_resolvers:
-            try:
-                return self._lazy_resolvers[key]()
-            except Exception:
-                return default
-        return default
-
-    def set(self, key: str, value: Any) -> None:
-        """Set a service or state value."""
-        self.services[key] = value
-
-    def set_state(self, key: str, value: Any) -> None:
-        """Set a runtime state value."""
-        self.state[key] = value
-
-    def get_state(self, key: str, default: Any = None) -> Any:
-        """Get a runtime state value."""
-        return self.state.get(key, default)
-
-    @property
-    def params(self) -> "PipelineParams | None":
-        """Get current pipeline params (for animation)."""
-        return self._params
-
-    @params.setter
-    def params(self, value: "PipelineParams") -> None:
-        """Set pipeline params (from animation controller)."""
-        self._params = value
-
-    def has_capability(self, capability: str) -> bool:
-        """Check if a capability is available."""
-        return capability in self.services or capability in self._lazy_resolvers
-
-
-class StageError(Exception):
-    """Raised when a stage fails to process."""
-
-    def __init__(self, stage_name: str, message: str, is_optional: bool = False):
-        self.stage_name = stage_name
-        self.message = message
-        self.is_optional = is_optional
-        super().__init__(f"Stage '{stage_name}' failed: {message}")
-
-
-def create_stage_error(
-    stage_name: str, error: Exception, is_optional: bool = False
-) -> StageError:
-    """Helper to create a StageError from an exception."""
-    return StageError(stage_name, str(error), is_optional)
diff --git a/engine/pipeline/registry.py b/engine/pipeline/registry.py
index 6e9bcac..8d04d5c 100644
--- a/engine/pipeline/registry.py
+++ b/engine/pipeline/registry.py
@@ -8,10 +8,10 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING, Any, TypeVar
 
-from engine.pipeline.core import Stage
+from engine.pipeline import Stage
 
 if TYPE_CHECKING:
-    from engine.pipeline.core import Stage
+    from engine.pipeline import Stage
 
 T = TypeVar("T")
 
diff --git a/engine/pipeline/stages/framebuffer.py b/engine/pipeline/stages/framebuffer.py
index 790be34..3df5a8b 100644
--- a/engine/pipeline/stages/framebuffer.py
+++ b/engine/pipeline/stages/framebuffer.py
@@ -14,7 +14,7 @@ from dataclasses import dataclass
 from typing import Any
 
 from engine.display import _strip_ansi
-from engine.pipeline.core import DataType, PipelineContext, Stage
+from engine.pipeline import DataType, PipelineContext, Stage
 
 
 @dataclass
diff --git a/engine/sensors/__init__.py b/engine/sensors/__init__.py
index 24dd5ff..bac7844 100644
--- a/engine/sensors/__init__.py
+++ b/engine/sensors/__init__.py
@@ -25,7 +25,7 @@ from dataclasses import dataclass
 from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
-    from engine.pipeline.core import PipelineContext
+    from engine.pipeline import PipelineContext
 
 
 @dataclass
@@ -166,13 +166,13 @@ class SensorStage:
 
     @property
     def inlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.ANY}
 
     @property
     def outlet_types(self) -> set:
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         return {DataType.ANY}
 
diff --git a/sideline/pipeline/controller.py b/sideline/pipeline/controller.py
index 301c1ab..765ee3b 100644
--- a/sideline/pipeline/controller.py
+++ b/sideline/pipeline/controller.py
@@ -423,7 +423,7 @@ class Pipeline:
             List of stages that were injected
         """
         from sideline.camera import Camera
-        from sideline.data_sources.sources import EmptyDataSource
+        from engine.data_sources.sources import EmptyDataSource
         from sideline.display import DisplayRegistry
         from sideline.pipeline.adapters import (
             CameraClockStage,
@@ -1033,7 +1033,7 @@ def create_pipeline_from_params(params: PipelineParams) -> Pipeline:
 
 def create_default_pipeline() -> Pipeline:
     """Create a default pipeline with all standard components."""
-    from sideline.data_sources.sources import HeadlinesDataSource
+    from engine.data_sources.sources import HeadlinesDataSource
     from sideline.pipeline.adapters import (
         DataSourceStage,
         SourceItemsToBufferStage,
diff --git a/tests/test_pipeline.py b/tests/test_pipeline.py
index 1e34287..dcc8148 100644
--- a/tests/test_pipeline.py
+++ b/tests/test_pipeline.py
@@ -15,7 +15,7 @@ from engine.pipeline import (
     create_default_pipeline,
     discover_stages,
 )
-from engine.pipeline.core import DataType, StageError
+from engine.pipeline import DataType, StageError
 
 
 class TestStageRegistry:
@@ -118,7 +118,7 @@ class TestPipeline:
 
     def test_build_resolves_dependencies(self):
         """Pipeline.build resolves execution order."""
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         pipeline = Pipeline()
         mock_source = MagicMock(spec=Stage)
@@ -153,7 +153,7 @@ class TestPipeline:
 
     def test_execute_runs_stages(self):
         """Pipeline.execute runs all stages in order."""
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         pipeline = Pipeline()
 
@@ -283,7 +283,7 @@ class TestCapabilityBasedDependencies:
     def test_capability_wildcard_resolution(self):
         """Pipeline resolves dependencies using wildcard capabilities."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class SourceStage(Stage):
             name = "headlines"
@@ -329,7 +329,7 @@ class TestCapabilityBasedDependencies:
     def test_missing_capability_raises_error(self):
         """Pipeline raises error when capability is missing."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage, StageError
+        from engine.pipeline import Stage, StageError
 
         class RenderStage(Stage):
             name = "render"
@@ -359,7 +359,7 @@ class TestCapabilityBasedDependencies:
     def test_multiple_stages_same_capability(self):
         """Pipeline uses first registered stage for capability."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class SourceA(Stage):
             name = "headlines"
@@ -458,8 +458,15 @@ class TestPipelineContext:
         """PipelineContext resolves lazy services."""
         ctx = PipelineContext()
 
+        # Register a lazy service resolver
+        from unittest.mock import MagicMock
+
+        mock_config = MagicMock()
+        ctx.register_service("config", lambda: mock_config)
+
         config = ctx.get("config")
         assert config is not None
+        assert config == mock_config
 
     def test_has_capability(self):
         """PipelineContext.has_capability checks for services."""
@@ -608,7 +615,7 @@ class TestStageAdapters:
         """DisplayStage.init initializes display."""
         from engine.display.backends.null import NullDisplay
         from engine.pipeline.adapters import DisplayStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
         from engine.pipeline.params import PipelineParams
 
         display = NullDisplay()
@@ -623,7 +630,7 @@ class TestStageAdapters:
         """DisplayStage.process forwards to display."""
         from engine.display.backends.null import NullDisplay
         from engine.pipeline.adapters import DisplayStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
         from engine.pipeline.params import PipelineParams
 
         display = NullDisplay()
@@ -640,7 +647,7 @@ class TestStageAdapters:
         """CameraStage applies camera transform."""
         from engine.camera import Camera, CameraMode
         from engine.pipeline.adapters import CameraStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
 
         camera = Camera(mode=CameraMode.FEED)
         stage = CameraStage(camera, name="vertical")
@@ -658,7 +665,7 @@ class TestStageAdapters:
         """
         from engine.camera import Camera, CameraMode
         from engine.pipeline.adapters import CameraStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
         from engine.pipeline.params import PipelineParams
 
         camera = Camera(mode=CameraMode.FEED)
@@ -696,7 +703,7 @@ class TestDataSourceStage:
 
         from engine.data_sources.sources import HeadlinesDataSource
         from engine.pipeline.adapters import DataSourceStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
 
         mock_items = [
             ("Test Headline 1", "TestSource", "12:00"),
@@ -739,7 +746,7 @@ class TestEffectPluginStage:
         """EffectPluginStage applies sensor param bindings."""
         from engine.effects.types import EffectConfig, EffectPlugin
         from engine.pipeline.adapters import EffectPluginStage
-        from engine.pipeline.core import PipelineContext
+        from engine.pipeline import PipelineContext
         from engine.pipeline.params import PipelineParams
 
         class SensorDrivenEffect(EffectPlugin):
@@ -772,7 +779,7 @@ class TestFullPipeline:
     def test_pipeline_circular_dependency_detection(self):
         """Pipeline detects circular dependencies."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class StageA(Stage):
             name = "a"
@@ -819,7 +826,7 @@ class TestPipelineMetrics:
     def test_metrics_collected(self):
         """Pipeline collects metrics when enabled."""
         from engine.pipeline.controller import Pipeline, PipelineConfig
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class DummyStage(Stage):
             name = "dummy"
@@ -842,7 +849,7 @@ class TestPipelineMetrics:
     def test_metrics_disabled(self):
         """Pipeline skips metrics when disabled."""
         from engine.pipeline.controller import Pipeline, PipelineConfig
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class DummyStage(Stage):
             name = "dummy"
@@ -864,7 +871,7 @@ class TestPipelineMetrics:
     def test_reset_metrics(self):
         """Pipeline.reset_metrics clears collected metrics."""
         from engine.pipeline.controller import Pipeline, PipelineConfig
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class DummyStage(Stage):
             name = "dummy"
@@ -894,7 +901,7 @@ class TestOverlayStages:
 
     def test_stage_is_overlay_property(self):
         """Stage has is_overlay property defaulting to False."""
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class TestStage(Stage):
             name = "test"
@@ -908,7 +915,7 @@ class TestOverlayStages:
 
     def test_stage_render_order_property(self):
         """Stage has render_order property defaulting to 0."""
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class TestStage(Stage):
             name = "test"
@@ -922,7 +929,7 @@ class TestOverlayStages:
 
     def test_stage_stage_type_property(self):
         """Stage has stage_type property defaulting to category."""
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class TestStage(Stage):
             name = "test"
@@ -937,7 +944,7 @@ class TestOverlayStages:
     def test_pipeline_get_overlay_stages(self):
         """Pipeline.get_overlay_stages returns overlay stages sorted by render_order."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class OverlayStageA(Stage):
             name = "overlay_a"
@@ -991,7 +998,7 @@ class TestOverlayStages:
     def test_pipeline_executes_overlays_after_regular(self):
         """Pipeline executes overlays after regular stages."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         call_order = []
 
@@ -1071,7 +1078,7 @@ class TestOverlayStages:
     def test_pipeline_get_stage_type(self):
         """Pipeline.get_stage_type returns stage_type for a stage."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class TestStage(Stage):
             name = "test"
@@ -1093,7 +1100,7 @@ class TestOverlayStages:
     def test_pipeline_get_render_order(self):
         """Pipeline.get_render_order returns render_order for a stage."""
         from engine.pipeline.controller import Pipeline
-        from engine.pipeline.core import Stage
+        from engine.pipeline import Stage
 
         class TestStage(Stage):
             name = "test"
@@ -1341,7 +1348,7 @@ class TestPipelineMutation:
         dependencies: set | None = None,
     ):
         """Helper to create a mock stage."""
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         mock = MagicMock(spec=Stage)
         mock.name = name
@@ -1693,7 +1700,7 @@ class TestPipelineMutation:
 
     def test_mutation_preserves_execution_for_remaining_stages(self):
         """Removing a stage doesn't break execution of remaining stages."""
-        from engine.pipeline.core import DataType
+        from engine.pipeline import DataType
 
         call_log = []