fix(playbook_loader): load generated playbooks from styles/custom/

lib/playbook_generator.save_playbook() writes generated playbooks to
styles/custom/, and the skills tell agents to save them there
(skills/meta/capability-extension.md, the animation and explainer
proposal directors). But this loader globs only the styles/ root, and it
is the loader tools/video/video_compose.py imports — so every generated
playbook was invisible at render time. The only way to make one work was
to hand-copy it up one directory, which is why custom playbooks end up
duplicated in both places.

Search styles/custom/ as a fallback in load_playbook() and merge it into
list_playbooks(), matching the semantics lib/playbook_generator.py
already uses: a preset wins when both exist, and the listing is deduped.
The not-found error now names both directories it searched instead of
just the last path it tried.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GYThSL15CujvBwD1wuUmr9

styles/playbook_loader.py

@@ -17,6 +17,10 @@ import yaml
 import jsonschema
 
 STYLES_DIR = Path(__file__).resolve().parent
+# Generated playbooks are written to styles/custom/ by
+# lib/playbook_generator.save_playbook(); both lookups below search it as a
+# fallback so those playbooks are visible to the render path.
+CUSTOM_SUBDIR = "custom"
 SCHEMA_PATH = (
     Path(__file__).resolve().parent.parent
     / "schemas"
@@ -33,6 +37,9 @@ def _load_playbook_schema() -> dict:
 def load_playbook(name: str, styles_dir: Optional[Path] = None) -> dict[str, Any]:
     """Load and validate a style playbook by name.
 
+    Presets live directly in the styles dir; generated playbooks live in its
+    ``custom/`` subdirectory. A preset wins when both exist.
+
     Args:
         name: Playbook name (without .yaml extension).
         styles_dir: Override directory for playbook files.
@@ -43,7 +50,12 @@ def load_playbook(name: str, styles_dir: Optional[Path] = None) -> dict[str, Any
     styles_dir = styles_dir or STYLES_DIR
     path = styles_dir / f"{name}.yaml"
     if not path.exists():
-        raise FileNotFoundError(f"Playbook not found: {path}")
+        path = styles_dir / CUSTOM_SUBDIR / f"{name}.yaml"
+    if not path.exists():
+        raise FileNotFoundError(
+            f"Playbook not found: {name!r} "
+            f"(searched {styles_dir} and {styles_dir / CUSTOM_SUBDIR})"
+        )
 
     with open(path, encoding="utf-8") as f:
         playbook = yaml.safe_load(f)
@@ -59,13 +71,17 @@ def validate_playbook(playbook: dict) -> None:
 
 
 def list_playbooks(styles_dir: Optional[Path] = None) -> list[str]:
-    """List all available playbook names."""
+    """List all available playbook names (presets + generated custom ones)."""
     styles_dir = styles_dir or STYLES_DIR
-    return [
+    names = [
         p.stem
         for p in styles_dir.glob("*.yaml")
         if p.stem != "__pycache__"
     ]
+    custom_dir = styles_dir / CUSTOM_SUBDIR
+    if custom_dir.exists():
+        names.extend(p.stem for p in custom_dir.glob("*.yaml"))
+    return sorted(set(names))
 
 
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