diff --git a/docs/prompt-pool-routing-map.md b/docs/prompt-pool-routing-map.md
index 28dde4a..85edd08 100644
--- a/docs/prompt-pool-routing-map.md
+++ b/docs/prompt-pool-routing-map.md
@@ -837,6 +837,9 @@ pair metadata through the core Python APIs, then verifies:
 
 - generated rows keep prompt, negative prompt, scene, composition, action item,
   and role graph metadata populated;
+- a user-added JSON category in a temporary category directory reaches category
+  choices, subcategory choices, prompt generation, and formatter metadata
+  routes without Python glue code;
 - Krea2, SDXL, and natural caption routes use metadata instead of text fallback;
 - SDXL and caption trigger handling keeps one trigger;
 - negative prompts do not duplicate comma-list items;
diff --git a/tools/prompt_smoke.py b/tools/prompt_smoke.py
index 638b509..7f36eca 100644
--- a/tools/prompt_smoke.py
+++ b/tools/prompt_smoke.py
@@ -1497,6 +1497,80 @@ def smoke_category_extensions_policy() -> None:
         "JSON pool_extensions did not reach legacy group scenes",
     )
 
+    previous_category_dir = category_library.CATEGORY_DIR
+    previous_extensions_applied = category_extensions._EXTENSIONS_APPLIED
+    try:
+        with tempfile.TemporaryDirectory() as temp_dir:
+            category_library.CATEGORY_DIR = Path(temp_dir)
+            category_extensions._EXTENSIONS_APPLIED = False
+            Path(temp_dir, "custom_category.json").write_text(
+                json.dumps(
+                    {
+                        "categories": {
+                            "Dev Test Wear": {
+                                "prompt_template": (
+                                    "{subject_phrase}: clean test style. {item_label}: {item}. "
+                                    "Scene: {scene}. Pose: {pose}. Facial expression: {expression}. "
+                                    "Composition: {composition}."
+                                ),
+                                "caption_template": "{subject_phrase}, {item}, {scene}, {composition}",
+                                "subcategories": {
+                                    "Layered Office": {
+                                        "items": ["structured test blazer over dark trousers"],
+                                        "scenes": ["temporary showroom with modular shelves"],
+                                        "poses": ["standing by a rail"],
+                                        "expressions": ["focused calm look"],
+                                        "compositions": ["centered catalog frame"],
+                                    }
+                                },
+                            }
+                        }
+                    },
+                    ensure_ascii=True,
+                ),
+                encoding="utf-8",
+            )
+            _expect("Dev Test Wear" in pb.category_choices(), "User-added JSON category did not reach category choices")
+            _expect(
+                "Dev Test Wear / Layered Office" in pb.subcategory_choices(),
+                "User-added JSON subcategory did not reach subcategory choices",
+            )
+            row = pb.build_prompt(
+                category="Dev Test Wear",
+                subcategory="Dev Test Wear / Layered Office",
+                row_number=1,
+                start_index=1,
+                seed=4109,
+                clothing="random",
+                ethnicity="any",
+                poses="random",
+                backside_bias=0.0,
+                figure="random",
+                no_plus_women=False,
+                no_black=False,
+                minimal_clothing_ratio=0.0,
+                standard_pose_ratio=1.0,
+                trigger=Trigger,
+                prepend_trigger_to_prompt=True,
+                extra_positive="",
+                extra_negative="",
+                women_count=1,
+                men_count=0,
+            )
+            _expect_row_base(row, "category_extensions_user_added_json")
+            _expect(row.get("source") == "json_category", "User-added JSON category did not use custom row route")
+            _expect(row.get("main_category") == "Dev Test Wear", "User-added JSON category name drifted")
+            _expect(row.get("subcategory") == "Layered Office", "User-added JSON subcategory name drifted")
+            _expect(row.get("item") == "structured test blazer over dark trousers", "User-added JSON item did not generate")
+            _expect(row.get("scene_text") == "temporary showroom with modular shelves", "User-added JSON scene did not generate")
+            _expect(row.get("pose") == "standing by a rail", "User-added JSON pose did not generate")
+            _expect(row.get("expression") == "focused calm look", "User-added JSON expression did not generate")
+            _expect(row.get("composition") == "centered catalog frame", "User-added JSON composition did not generate")
+            _expect_formatter_outputs(row, "category_extensions_user_added_json", target="single")
+    finally:
+        category_library.CATEGORY_DIR = previous_category_dir
+        category_extensions._EXTENSIONS_APPLIED = previous_extensions_applied
+
 
 def smoke_category_cast_config_policy() -> None:
     _expect(pb.CATEGORY_PRESETS is category_cast_config.CATEGORY_PRESETS, "Prompt builder category presets are not delegated")