engine/pipeline/adapters.py

@@ -111,7 +111,7 @@ class DisplayStage(Stage):
 
     @property
     def dependencies(self) -> set[str]:
-        return set()
+        return {"render.output"}  # Display needs rendered content
 
     def init(self, ctx: PipelineContext) -> bool:
         w = ctx.params.viewport_width if ctx.params else 80

engine/pipeline/controller.py

@@ -520,7 +520,10 @@ def create_pipeline_from_params(params: PipelineParams) -> Pipeline:
 def create_default_pipeline() -> Pipeline:
     """Create a default pipeline with all standard components."""
     from engine.data_sources.sources import HeadlinesDataSource
-    from engine.pipeline.adapters import DataSourceStage
+    from engine.pipeline.adapters import (
+        DataSourceStage,
+        SourceItemsToBufferStage,
+    )
 
     pipeline = Pipeline()
 
@@ -528,6 +531,9 @@ def create_default_pipeline() -> Pipeline:
     source = HeadlinesDataSource()
     pipeline.add_stage("source", DataSourceStage(source, name="headlines"))
 
+    # Add render stage to convert items to text buffer
+    pipeline.add_stage("render", SourceItemsToBufferStage(name="items-to-buffer"))
+
     # Add display stage
     display = StageRegistry.create("display", "terminal")
     if display:

tests/test_adapters.py

@@ -97,10 +97,10 @@ class TestDisplayStage:
         assert "display.output" in stage.capabilities
 
     def test_display_stage_dependencies(self):
-        """DisplayStage has no dependencies."""
+        """DisplayStage depends on render.output."""
         mock_display = MagicMock()
         stage = DisplayStage(mock_display, name="terminal")
-        assert stage.dependencies == set()
+        assert "render.output" in stage.dependencies
 
     def test_display_stage_init(self):
         """DisplayStage.init() calls display.init() with dimensions."""