refactor(xcf_stack): use explicit inputs for layer list and scheduling

Replace prior_steps and runs_last with inputs=[...] step refs so GIMP
export waits only on listed layers. Add rezepttest pipeline and
bokeh-oktagon recipe.

Co-authored-by: Cursor <cursoragent@cursor.com>

RECIPES.md

@@ -24,7 +24,7 @@ Not executable code. Named building blocks for creating or editing pipelines in
    ```
 
 6. **Shared expensive steps** — `rembg` runs once per pipeline and is reused. Recipe lines say `rembg`, but the agent must not re-run it for every composite.
-7. **`xcf_stack` (GIMP export)** — stacks **all prior step outputs** (plus `input/` by default) into one `.xcf` per image with layers named after step ids. Usually the **last step** after all composites. Requires `gimp` on PATH. Not a layer inside a `combine` block — a separate finishing recipe.
+7. **`xcf_stack` (GIMP export)** — stacks **listed step outputs** into one `.xcf` per image. Pass step refs in `inputs=[...]` (bottom layer → top). The runner waits until all listed steps finish. Requires `gimp` on PATH. Not a layer inside a `combine` block — a separate recipe.
 8. **Placeholders** — `COLOR1`, `COLOR2`, `COLOR`, `STYLE`, `MAX_EDGE`, `PROMPT`, `MODEL`, `TEMPLATE_IMAGE`, etc. are filled in at pipeline creation time (from your prompt or constants at the top of the script).
 9. **Colors** — hex for backgrounds (`#RRGGBB` or `#RRGGBBAA`). G'MIC filters need `R,G,B` tuples (see [GMIC color derivation](#6-gmic-color-derivation) below).
 10. **Single-step vs composite vs pipeline** — one declarative line = one module step. Multiple indented lines in a **composite** recipe = layers (bottom → top). Multiple indented lines in a **pipeline** recipe = sequential steps (first step first, output feeds the next).
@@ -67,7 +67,7 @@ Not executable code. Named building blocks for creating or editing pipelines in
 - **Recipe inclusion:** if an indented line is a known recipe id (e.g. `colorsplash` inside `colorsplash-watermark`), look up that recipe, expand it, and use its output as the input for the next step. Expand recursively. Do not duplicate shared steps — one `rembg` (etc.) per pipeline when multiple included recipes need it.
 - **Pipeline vs composite:** multiple indented lines that are **sequential steps or recipe refs** = pipeline recipe (chain). Multiple indented **layer** lines (original, rembg, backgrounds, gmic-on-rembg, …) = composite recipe (combine). When unsure: if any line is another recipe id, treat the parent as a pipeline recipe.
 - **Ignore notes:** skip any line that is only a `#` comment (after indent trim). Strip inline `# …` suffixes on recipe-id lines. Do not copy note text into Python comments unless Fränky asks.
-- **`xcf_stack`:** when a pipeline includes recipe `xcf-stack` (or the user asks for GIMP layers), append as the final step: `p.step("xcf_stack", inputs="input")`. The module auto-collects `prior_steps` from the runner — do not list every composite as explicit inputs. See `imagepipeline/modules/xcf_stack.py`.
+- **`xcf_stack`:** list every layer source in `inputs=[...]` (bottom → top). Include `"input"` for the original. The runner schedules `xcf_stack` after all listed steps complete. See `imagepipeline/modules/xcf_stack.py` and `pipelines/pipeline_rezepttest.py`.
 - **Shared steps:** define `rembg` (and other expensive steps) **once** per pipeline and reference the step in composites — mirror `pipelines/pipeline_baxxter.py`.
 - Follow the **Rules cheat sheet** above — especially layer order and chained composites.
 - **3+ layers:** chain `composite` steps (see baxxter, crusaders, orange).
@@ -87,14 +87,14 @@ Not executable code. Named building blocks for creating or editing pipelines in
 | `gradient background COLOR1 COLOR2 radial` | `imagemagick_fill` radial |
 | `COLOR background` | `imagemagick_fill` solid `color1=COLOR` |
 | `rembg with gmic: FILTER` | `gmic` on rembg output; command = `-FILTER` |
+| `original with gmic: FILTER` | `gmic` on input; command = `-FILTER` |
 | `layer opacity N%` | `composite` `foreground_opacity=N/100` on that layer |
 | `make layer 5% bigger then crop to original size` | `imagemagick_scale_crop` `scale=1.05` |
 | `COLOR to alpha` | `color_to_alpha` `color=COLOR` |
 | `resize max edge MAX_EDGE` | `imagemagick_resize` `max_edge=MAX_EDGE` |
 | `crop square` | `crop_square` |
 | `darktable style STYLE` | `darktable_style` `style=STYLE` |
-| `xcf stack all steps` | `xcf_stack` — GIMP layer export of all prior steps |
+| `xcf stack layers: LAYER1, LAYER2, …` | `xcf_stack` with `inputs=[...]` in that order |
-| `xcf stack without input` | `xcf_stack` `include_input=false` |
 | `xcf stack skip missing` | `xcf_stack` `skip_missing=true` |
 | `openrouter edit PROMPT MODEL` | `openrouter_edit` |
 | `openrouter gallery match TEMPLATE_IMAGE` | `openrouter_edit` with `template_image` |
@@ -230,24 +230,15 @@ crop-square
 
 ```text
 xcf-stack  # GIMP layer export — one .xcf per input image
-  xcf stack all steps
+  xcf stack layers: input, rembg, composite_01, composite_02, …
 ```
 
-- **Module:** `xcf_stack` — `p.step("xcf_stack", inputs="input")` as **last step**
+- **Module:** `xcf_stack` — `p.step("xcf_stack", inputs=["input", step_a, step_b, …])`
-- **Layer order in XCF:** `input/` (bottom, default) then prior steps in pipeline definition order
+- **Layer order in XCF:** same as `inputs` list (bottom → top); GIMP layer names = step ids (`input` for originals)
 - **Matching:** layers matched by filename stem (extension may differ, e.g. rembg `.png` on `.jpg` input)
 - **Output:** `{stem}.xcf` per input image
 - **Requires:** `gimp` on PATH
-- **No existing pipeline uses this yet** — append to any multi-output pipeline (e.g. baxxter variants + `xcf-stack`)
+- **Source:** `pipelines/pipeline_rezepttest.py`
-
-### xcf-stack-no-input
-
-```text
-xcf-stack-no-input
-  xcf stack without input
-```
-
-- **Module:** `xcf_stack` — `include_input=False`
 
 ### xcf-stack-skip-missing
 
@@ -461,6 +452,19 @@ original-jpr-smooth-rembg
 - **Middle layer:** jpr smooth on rembg, then scale 5% + center crop
 - **Source:** baxxter, crusaders
 
+### bokeh-oktagon
+
+```text
+bokeh-oktagon
+  original
+  original with gmic: fx_bokeh 3,5,0,30,8,4,0.3,0.2,R1,G1,B1,ALPHA1,0.7,30,20,20,1,2,R2,G2,B2,ALPHA2,0.15
+  rembg
+```
+
+- **3 layers:** composite(original, input_bokeh) → composite(result, rembg)
+- **Colors:** `R1,G1,B1` from **COLOR1**; `R2,G2,B2` from **COLOR2**; `ALPHA1` / `ALPHA2` are 0–255 (defaults 160 / 110)
+- **G'MIC:** octagonal bokeh discs — first color pair `R1,G1,B1,ALPHA1`, second `R2,G2,B2,ALPHA2`
+
 ### original-jpr-smooth-grey-alpha-rembg
 
 ```text
@@ -556,6 +560,7 @@ G'MIC commands in parameterized recipes use **comma-separated RGB integers**, no
 | `original-bwrecolor-rembg` | highlight `R2,G2,B2`, accent `R1,G1,B1` in `fx_bwrecolorize` |
 | `rembg-custom-gradient-a` | starts with `R1,G1,B1`, transitions via `R2,G2,B2` |
 | `rembg-custom-gradient-b` | starts with `R2,G2,B2`, transitions via `R1,G1,B1` |
+| `bokeh-oktagon` | bokeh tints `R1,G1,B1,ALPHA1` and `R2,G2,B2,ALPHA2` in `fx_bokeh` |
 | `imagemagick_fill` backgrounds | use full hex including alpha if needed (`#d7fd00ff`) |
 
 ### Agent workflow
@@ -596,7 +601,12 @@ colorsplash-watermark
 Create pipeline "foo" with recipes colorsplash, rembg-radial-2colors, and xcf-stack
 ```
 
-Agent: all composite outputs first, then `p.step("xcf_stack", inputs="input")` as the final step.
+Agent: build all composite steps, then `p.step("xcf_stack", inputs=["input", rembg_out, …, composite_final])` listing every layer bottom → top.
+
+```text
+xcf-stack
+  xcf stack layers: input, rembg, composite_colorsplash, composite_radial, …
+```
 
 ### Full combine list (baxxter style)
 

imagepipeline/core/context.py

@@ -18,7 +18,8 @@ class ModuleContext:
     pipeline_output_root: Path
     step_id: str
     matched_groups: list[list[Path]] = field(default_factory=list)
-    prior_steps: list[tuple[str, Path]] = field(default_factory=list)
+    input_refs: list[str] = field(default_factory=list)
+    input_layer_dirs: list[tuple[str, Path]] = field(default_factory=list)
     logger: PipelineLogger | None = None
 
     @property

imagepipeline/core/runner.py

@@ -151,9 +151,23 @@ class PipelineRunner:
         step.module.check_dependencies()
         validated = step.module.validate_module_params(step.params)
 
-        source_lists = [self._resolve_source_paths(ref) for ref in step.input_refs]
+        if step.module_name == "xcf_stack":
-        matched_groups = match_by_stem(source_lists)
+            if not step.input_refs:
-        input_paths = flatten_matched(matched_groups)
+                raise ValidationError("xcf_stack requires at least one input layer")
+            source_lists = [self._resolve_source_paths(ref) for ref in step.input_refs]
+            input_paths = source_lists[0]
+            matched_groups = [[path] for path in input_paths]
+            input_layer_dirs: list[tuple[str, Path]] = []
+            for ref in step.input_refs:
+                if ref == INPUT_SOURCE:
+                    input_layer_dirs.append(("input", self._input_link_dir))
+                else:
+                    input_layer_dirs.append((ref, self._results[ref].output_dir))
+        else:
+            source_lists = [self._resolve_source_paths(ref) for ref in step.input_refs]
+            matched_groups = match_by_stem(source_lists)
+            input_paths = flatten_matched(matched_groups)
+            input_layer_dirs = []
 
         output_dir = self.output_root / step.output_dir_name
         output_dir.mkdir(parents=True, exist_ok=True)
@@ -220,7 +234,8 @@ class PipelineRunner:
             pipeline_output_root=self.output_root,
             step_id=step.step_id,
             matched_groups=matched_groups,
-            prior_steps=[(sid, res.output_dir) for sid, res in self._results.items()],
+            input_refs=list(step.input_refs),
+            input_layer_dirs=input_layer_dirs,
             logger=self.logger,
         )
 
@@ -280,7 +295,4 @@ class PipelineRunner:
         if len(ordered_ids) != len(self.steps):
             raise CycleError("Pipeline contains a cycle in step dependencies")
 
-        ordered = [step_by_id[step_id] for step_id in ordered_ids]
+        return [step_by_id[step_id] for step_id in ordered_ids]
-        deferred = [step for step in ordered if step.module.runs_last]
-        regular = [step for step in ordered if not step.module.runs_last]
-        return regular + deferred

imagepipeline/modules/base.py

@@ -14,7 +14,6 @@ class BaseModule(ABC):
 
     name: ClassVar[str]
     description: ClassVar[str] = ""
-    runs_last: ClassVar[bool] = False
     supported_input_formats: ClassVar[tuple[str, ...]] = (
         ".jpg",
         ".jpeg",

imagepipeline/modules/xcf_stack.py

@@ -4,18 +4,22 @@ from pathlib import Path
 
 from imagepipeline.core.context import ModuleContext
 from imagepipeline.core.params import Param
+from imagepipeline.core.step import INPUT_SOURCE
 from imagepipeline.modules.base import SubprocessModule
 from imagepipeline.modules.registry import register
 from imagepipeline.utils.files import find_image_by_stem
 from imagepipeline.utils.gimp import stack_images_to_xcf
 
 
+def _layer_name(ref: str) -> str:
+    return "input" if ref == INPUT_SOURCE else ref
+
+
 @register
 class XcfStackModule(SubprocessModule):
     name = "xcf_stack"
-    runs_last = True
     description = (
-        "Stack all prior pipeline step outputs as GIMP layers into one XCF per image"
+        "Stack listed pipeline step outputs as GIMP layers into one XCF per image"
     )
     command_candidates = ("gimp-console", "gimp")
 
@@ -32,11 +36,6 @@ class XcfStackModule(SubprocessModule):
     @classmethod
     def parameters(cls) -> dict[str, Param]:
         return {
-            "include_input": Param(
-                "bool",
-                default=True,
-                help="Include pipeline input/ directory as bottom layer",
-            ),
             "skip_missing": Param(
                 "bool",
                 default=False,
@@ -50,19 +49,13 @@ class XcfStackModule(SubprocessModule):
         }
 
     def run(self, ctx: ModuleContext) -> None:
-        include_input = ctx.params["include_input"]
         skip_missing = ctx.params["skip_missing"]
         timeout = ctx.params["timeout"]
 
-        layer_sources: list[tuple[str, Path]] = []
+        if not ctx.input_layer_dirs:
-        if include_input:
-            layer_sources.append(("input", ctx.pipeline_output_root / "input"))
-        layer_sources.extend(ctx.prior_steps)
-
-        if not layer_sources:
             raise ValueError(
-                "xcf_stack has no layer sources "
+                "xcf_stack requires at least one input layer "
-                "(include_input=False and no prior_steps)"
+                "(pass step refs in inputs=[...], bottom to top)"
             )
 
         ctx.output_dir.mkdir(parents=True, exist_ok=True)
@@ -73,19 +66,19 @@ class XcfStackModule(SubprocessModule):
             stem = input_path.stem
             layers: list[tuple[str, Path]] = []
 
-            for step_id, directory in layer_sources:
+            for ref, directory in ctx.input_layer_dirs:
                 image_path = find_image_by_stem(directory, stem)
                 if image_path is None:
                     if not skip_missing:
                         raise ValueError(
                             f"xcf_stack: no image with stem '{stem}' in step "
-                            f"'{step_id}' ({directory})"
+                            f"'{_layer_name(ref)}' ({directory})"
                         )
                     continue
-                layers.append((step_id, image_path))
+                layers.append((_layer_name(ref), image_path))
 
             if not layers:
-                checked = ", ".join(step_id for step_id, _ in layer_sources)
+                checked = ", ".join(name for name, _ in ctx.input_layer_dirs)
                 raise ValueError(
                     f"xcf_stack: no layers found for stem '{stem}' "
                     f"(checked: {checked})"

pipelines/pipeline_rezepttest.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+"""Rezepttest pipeline — RECIPES.md smoke test (Indians Aichelberg logo colors)."""
+
+from pathlib import Path
+
+from imagepipeline import Pipeline
+
+# Change to your Darktable export folder.
+INPUT = Path("/home/frank/tmp/bar")
+OUTPUT_BASE = Path.home() / "pipeline_output"
+
+EXISTING_OUTPUTS: dict[str, Path] = {}
+CONTINUE_FROM: Path | None = None
+
+# Colors from Indians Aichelberg logo (orange text + red stitching).
+COLOR1 = "#f0b020"  # 240, 176, 32
+COLOR2 = "#f01000"  # 240, 16, 0
+
+ALPHA1 = 160
+ALPHA2 = 110
+
+GMIC_DROP_SHADOW = "-fx_drop_shadow3d 0,0,0,10,1,1,2,0.5,240,16,0,200,0"
+GMIC_JPR_SMOOTH = "-jpr_gradient_smooth 0,1.5"
+GMIC_BOKEH = (
+    f"-fx_bokeh 3,5,0,30,8,4,0.3,0.2,240,176,32,{ALPHA1},0.7,30,20,20,1,2,"
+    f"240,16,0,{ALPHA2},0.15"
+)
+
+
+def main() -> None:
+    with Pipeline(
+        name="rezepttest",
+        input_dir=INPUT,
+        output_base=OUTPUT_BASE,
+        existing_outputs=EXISTING_OUTPUTS or None,
+        continue_from=CONTINUE_FROM,
+    ) as p:
+        rembg_out = p.step("rembg", inputs="input")
+        grayscale = p.step("gmic_grayscale", inputs="input")
+        gradient_radial_bg = p.step(
+            "imagemagick_fill",
+            inputs="input",
+            color1=COLOR1,
+            color2=COLOR2,
+            gradient=True,
+            radial=True,
+        )
+
+        rembg_shadow = p.step("gmic", inputs=rembg_out, command=GMIC_DROP_SHADOW)
+        rembg_jpr_smooth = p.step("gmic", inputs=rembg_out, command=GMIC_JPR_SMOOTH)
+        rembg_jpr_smooth_sized = p.step(
+            "imagemagick_scale_crop",
+            inputs=rembg_jpr_smooth,
+            scale=1.05,
+        )
+        input_bokeh = p.step("gmic", inputs="input", command=GMIC_BOKEH)
+
+        # recipe: colorsplash
+        composite_colorsplash = p.step("composite", inputs=[grayscale, rembg_out])
+
+        # recipe: rembg-radial-2colors (gradient-radial)
+        composite_radial = p.step("composite", inputs=[gradient_radial_bg, rembg_out])
+
+        # recipe: original-drop-shadow-rembg
+        shadow_mid = p.step("composite", inputs=["input", rembg_shadow])
+        composite_shadow = p.step("composite", inputs=[shadow_mid, rembg_out])
+
+        # recipe: original-jpr-smooth-rembg
+        smooth_mid = p.step("composite", inputs=["input", rembg_jpr_smooth_sized])
+        composite_smooth = p.step("composite", inputs=[smooth_mid, rembg_out])
+
+        # recipe: bokeh-oktagon
+        bokeh_mid = p.step("composite", inputs=["input", input_bokeh])
+        composite_bokeh = p.step("composite", inputs=[bokeh_mid, rembg_out])
+
+        # recipe: xcf-stack — explicit layer list, bottom to top
+        p.step(
+            "xcf_stack",
+            inputs=[
+                "input",
+                rembg_out,
+                grayscale,
+                gradient_radial_bg,
+                rembg_shadow,
+                rembg_jpr_smooth_sized,
+                input_bokeh,
+                composite_colorsplash,
+                composite_radial,
+                composite_shadow,
+                composite_smooth,
+                composite_bokeh,
+            ],
+        )
+
+        output_root = p.run()
+
+    print(f"Pipeline finished. Output: {output_root}")
+
+
+if __name__ == "__main__":
+    main()

tests/test_xcf_stack.py

@@ -41,7 +41,7 @@ class TestModuleRegistration:
     def test_get_module_returns_xcf_stack_class(self) -> None:
         assert get_module("xcf_stack") is XcfStackModule
 
-    def test_xcf_stack_runs_last(self) -> None:
+    def test_xcf_stack_waits_for_layer_inputs(self) -> None:
         from imagepipeline.core.runner import PipelineRunner
         from imagepipeline.core.step import StepDefinition
         from imagepipeline.modules.imagemagick_grayscale import ImageMagickGrayscale
@@ -51,7 +51,7 @@ class TestModuleRegistration:
                 step_id="xcf_stack_01",
                 module_name="xcf_stack",
                 module=XcfStackModule,
-                input_refs=["input"],
+                input_refs=["input", "imagemagick_grayscale_01"],
                 params={},
                 output_dir_name="xcf_stack_01",
             ),
@@ -71,7 +71,10 @@ class TestModuleRegistration:
             steps=steps,
         )
         ordered = runner._topological_sort()
-        assert ordered[-1].module_name == "xcf_stack"
+        assert [step.step_id for step in ordered] == [
+            "imagemagick_grayscale_01",
+            "xcf_stack_01",
+        ]
 
 
 class TestExpectedOutputFilenames:
@@ -116,7 +119,7 @@ def _make_stack_fixture(tmp_path: Path) -> dict[str, Path]:
 
 class TestXcfStackRun:
     @patch("imagepipeline.modules.xcf_stack.stack_images_to_xcf")
-    def test_collects_layers_from_input_and_prior_steps(
+    def test_collects_layers_from_explicit_inputs(
         self, mock_stack: object, tmp_path: Path
     ) -> None:
         paths = _make_stack_fixture(tmp_path)
@@ -130,7 +133,8 @@ class TestXcfStackRun:
             params=XcfStackModule.validate_module_params({}),
             pipeline_output_root=paths["root"],
             step_id="xcf_stack_01",
-            prior_steps=[
+            input_layer_dirs=[
+                ("input", paths["input_dir"]),
                 ("step_a", paths["step_a"]),
                 ("step_b", paths["step_b"]),
             ],
@@ -161,7 +165,8 @@ class TestXcfStackRun:
             params=XcfStackModule.validate_module_params({"skip_missing": True}),
             pipeline_output_root=paths["root"],
             step_id="xcf_stack_01",
-            prior_steps=[
+            input_layer_dirs=[
+                ("input", paths["input_dir"]),
                 ("step_a", paths["step_a"]),
                 ("step_b", paths["step_b"]),
             ],
@@ -187,7 +192,8 @@ class TestXcfStackRun:
             params=XcfStackModule.validate_module_params({"skip_missing": False}),
             pipeline_output_root=paths["root"],
             step_id="xcf_stack_01",
-            prior_steps=[
+            input_layer_dirs=[
+                ("input", paths["input_dir"]),
                 ("step_a", paths["step_a"]),
                 ("step_b", paths["step_b"]),
             ],