Improve ProjectLoaderDynamic UX: single node, error feedback, auto-refresh

Remove 3 redundant hardcoded nodes (Standard/VACE/LoRA), keeping only the
Dynamic node. Add total_sequences INT output (slot 0) for loop counting.
Add structured error handling: _fetch_json returns typed error dicts,
load_dynamic raises RuntimeError with descriptive messages, JS shows
red border/title on errors. Add 500ms debounced auto-refresh on widget
changes. Add 404s for missing project/file in API endpoints.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api_routes.py

@@ -55,13 +55,26 @@ def _list_sequences(name: str, file_name: str) -> dict[str, Any]:
 
 def _get_data(name: str, file_name: str, seq: int = Query(default=1)) -> dict[str, Any]:
     db = _get_db()
-    data = db.query_sequence_data(name, file_name, seq)
+    proj = db.get_project(name)
+    if not proj:
+        raise HTTPException(status_code=404, detail=f"Project '{name}' not found")
+    df = db.get_data_file_by_names(name, file_name)
+    if not df:
+        raise HTTPException(status_code=404, detail=f"File '{file_name}' not found in project '{name}'")
+    data = db.get_sequence(df["id"], seq)
     if data is None:
-        raise HTTPException(status_code=404, detail="Sequence not found")
+        raise HTTPException(status_code=404, detail=f"Sequence {seq} not found")
     return data
 
 
 def _get_keys(name: str, file_name: str, seq: int = Query(default=1)) -> dict[str, Any]:
     db = _get_db()
-    keys, types = db.query_sequence_keys(name, file_name, seq)
+    proj = db.get_project(name)
-    return {"keys": keys, "types": types}
+    if not proj:
+        raise HTTPException(status_code=404, detail=f"Project '{name}' not found")
+    df = db.get_data_file_by_names(name, file_name)
+    if not df:
+        raise HTTPException(status_code=404, detail=f"File '{file_name}' not found in project '{name}'")
+    keys, types = db.get_sequence_keys(df["id"], seq)
+    total = db.count_sequences(df["id"])
+    return {"keys": keys, "types": types, "total_sequences": total}

db.py

@@ -182,6 +182,21 @@ class ProjectDB:
         ).fetchall()
         return [r["sequence_number"] for r in rows]
 
+    def count_sequences(self, data_file_id: int) -> int:
+        """Return the number of sequences for a data file."""
+        row = self.conn.execute(
+            "SELECT COUNT(*) AS cnt FROM sequences WHERE data_file_id = ?",
+            (data_file_id,),
+        ).fetchone()
+        return row["cnt"]
+
+    def query_total_sequences(self, project_name: str, file_name: str) -> int:
+        """Return total sequence count by project and file names."""
+        df = self.get_data_file_by_names(project_name, file_name)
+        if not df:
+            return 0
+        return self.count_sequences(df["id"])
+
     def get_sequence_keys(self, data_file_id: int, sequence_number: int) -> tuple[list[str], list[str]]:
         """Returns (keys, types) for a sequence's data dict."""
         data = self.get_sequence(data_file_id, sequence_number)

project_loader.py

@@ -39,13 +39,31 @@ def to_int(val: Any) -> int:
 
 
 def _fetch_json(url: str) -> dict:
-    """Fetch JSON from a URL using stdlib urllib."""
+    """Fetch JSON from a URL using stdlib urllib.
+
+    On error, returns a dict with an "error" key describing the failure.
+    """
     try:
         with urllib.request.urlopen(url, timeout=5) as resp:
             return json.loads(resp.read())
-    except (urllib.error.URLError, json.JSONDecodeError, OSError) as e:
+    except urllib.error.HTTPError as e:
-        logger.warning(f"Failed to fetch {url}: {e}")
+        # HTTPError is a subclass of URLError — must be caught first
-        return {}
+        body = ""
+        try:
+            raw = e.read()
+            detail = json.loads(raw)
+            body = detail.get("detail", str(raw, "utf-8", errors="replace"))
+        except Exception:
+            body = str(e)
+        logger.warning(f"HTTP {e.code} from {url}: {body}")
+        return {"error": "http_error", "status": e.code, "message": body}
+    except (urllib.error.URLError, OSError) as e:
+        reason = str(e.reason) if hasattr(e, "reason") else str(e)
+        logger.warning(f"Network error fetching {url}: {reason}")
+        return {"error": "network_error", "message": reason}
+    except json.JSONDecodeError as e:
+        logger.warning(f"Invalid JSON from {url}: {e}")
+        return {"error": "parse_error", "message": str(e)}
 
 
 def _fetch_data(manager_url: str, project: str, file: str, seq: int) -> dict:
@@ -100,6 +118,9 @@ if PromptServer is not None:
         except (ValueError, TypeError):
             seq = 1
         data = _fetch_keys(manager_url, project, file_name, seq)
+        if data.get("error") in ("http_error", "network_error", "parse_error"):
+            status = data.get("status", 502)
+            return web.json_response(data, status=status)
         return web.json_response(data)
 
 
@@ -124,15 +145,25 @@ class ProjectLoaderDynamic:
             },
         }
 
-    RETURN_TYPES = tuple(any_type for _ in range(MAX_DYNAMIC_OUTPUTS))
+    RETURN_TYPES = ("INT",) + tuple(any_type for _ in range(MAX_DYNAMIC_OUTPUTS))
-    RETURN_NAMES = tuple(f"output_{i}" for i in range(MAX_DYNAMIC_OUTPUTS))
+    RETURN_NAMES = ("total_sequences",) + tuple(f"output_{i}" for i in range(MAX_DYNAMIC_OUTPUTS))
     FUNCTION = "load_dynamic"
     CATEGORY = "utils/json/project"
     OUTPUT_NODE = False
 
     def load_dynamic(self, manager_url, project_name, file_name, sequence_number,
                      output_keys="", output_types=""):
+        # Fetch keys metadata (includes total_sequences count)
+        keys_meta = _fetch_keys(manager_url, project_name, file_name, sequence_number)
+        if keys_meta.get("error") in ("http_error", "network_error", "parse_error"):
+            msg = keys_meta.get("message", "Unknown error")
+            raise RuntimeError(f"Failed to fetch project keys: {msg}")
+        total_sequences = keys_meta.get("total_sequences", 0)
+
         data = _fetch_data(manager_url, project_name, file_name, sequence_number)
+        if data.get("error") in ("http_error", "network_error", "parse_error"):
+            msg = data.get("message", "Unknown error")
+            raise RuntimeError(f"Failed to fetch sequence data: {msg}")
 
         # Parse keys — try JSON array first, fall back to comma-split for compat
         keys = []
@@ -171,111 +202,14 @@ class ProjectLoaderDynamic:
         while len(results) < MAX_DYNAMIC_OUTPUTS:
             results.append("")
 
-        return tuple(results)
+        return (total_sequences,) + tuple(results)
-
-
-# ==========================================
-# 1. STANDARD NODE (Project-based I2V)
-# ==========================================
-
-class ProjectLoaderStandard:
-    @classmethod
-    def INPUT_TYPES(s):
-        return {"required": {
-            "manager_url": ("STRING", {"default": "http://localhost:8080", "multiline": False}),
-            "project_name": ("STRING", {"default": "", "multiline": False}),
-            "file_name": ("STRING", {"default": "", "multiline": False}),
-            "sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
-        }}
-
-    RETURN_TYPES = ("STRING", "STRING", "STRING", "STRING", "STRING", "FLOAT", "INT", "STRING", "STRING", "STRING")
-    RETURN_NAMES = ("general_prompt", "general_negative", "current_prompt", "negative", "camera", "flf", "seed", "video_file_path", "reference_image_path", "flf_image_path")
-    FUNCTION = "load_standard"
-    CATEGORY = "utils/json/project"
-
-    def load_standard(self, manager_url, project_name, file_name, sequence_number):
-        data = _fetch_data(manager_url, project_name, file_name, sequence_number)
-        return (
-            str(data.get("general_prompt", "")), str(data.get("general_negative", "")),
-            str(data.get("current_prompt", "")), str(data.get("negative", "")),
-            str(data.get("camera", "")), to_float(data.get("flf", 0.0)),
-            to_int(data.get("seed", 0)), str(data.get("video file path", "")),
-            str(data.get("reference image path", "")), str(data.get("flf image path", ""))
-        )
-
-
-# ==========================================
-# 2. VACE NODE (Project-based)
-# ==========================================
-
-class ProjectLoaderVACE:
-    @classmethod
-    def INPUT_TYPES(s):
-        return {"required": {
-            "manager_url": ("STRING", {"default": "http://localhost:8080", "multiline": False}),
-            "project_name": ("STRING", {"default": "", "multiline": False}),
-            "file_name": ("STRING", {"default": "", "multiline": False}),
-            "sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
-        }}
-
-    RETURN_TYPES = ("STRING", "STRING", "STRING", "STRING", "STRING", "FLOAT", "INT", "INT", "INT", "INT", "STRING", "INT", "INT", "STRING", "STRING")
-    RETURN_NAMES = ("general_prompt", "general_negative", "current_prompt", "negative", "camera", "flf", "seed", "frame_to_skip", "input_a_frames", "input_b_frames", "reference_path", "reference_switch", "vace_schedule", "video_file_path", "reference_image_path")
-    FUNCTION = "load_vace"
-    CATEGORY = "utils/json/project"
-
-    def load_vace(self, manager_url, project_name, file_name, sequence_number):
-        data = _fetch_data(manager_url, project_name, file_name, sequence_number)
-        return (
-            str(data.get("general_prompt", "")), str(data.get("general_negative", "")),
-            str(data.get("current_prompt", "")), str(data.get("negative", "")),
-            str(data.get("camera", "")), to_float(data.get("flf", 0.0)),
-            to_int(data.get("seed", 0)), to_int(data.get("frame_to_skip", 81)),
-            to_int(data.get("input_a_frames", 16)), to_int(data.get("input_b_frames", 16)),
-            str(data.get("reference path", "")), to_int(data.get("reference switch", 1)),
-            to_int(data.get("vace schedule", 1)), str(data.get("video file path", "")),
-            str(data.get("reference image path", ""))
-        )
-
-
-# ==========================================
-# 3. LoRA NODE (Project-based)
-# ==========================================
-
-class ProjectLoaderLoRA:
-    @classmethod
-    def INPUT_TYPES(s):
-        return {"required": {
-            "manager_url": ("STRING", {"default": "http://localhost:8080", "multiline": False}),
-            "project_name": ("STRING", {"default": "", "multiline": False}),
-            "file_name": ("STRING", {"default": "", "multiline": False}),
-            "sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
-        }}
-
-    RETURN_TYPES = ("STRING", "STRING", "STRING", "STRING", "STRING", "STRING")
-    RETURN_NAMES = ("lora_1_high", "lora_1_low", "lora_2_high", "lora_2_low", "lora_3_high", "lora_3_low")
-    FUNCTION = "load_loras"
-    CATEGORY = "utils/json/project"
-
-    def load_loras(self, manager_url, project_name, file_name, sequence_number):
-        data = _fetch_data(manager_url, project_name, file_name, sequence_number)
-        return (
-            str(data.get("lora 1 high", "")), str(data.get("lora 1 low", "")),
-            str(data.get("lora 2 high", "")), str(data.get("lora 2 low", "")),
-            str(data.get("lora 3 high", "")), str(data.get("lora 3 low", ""))
-        )
 
 
 # --- Mappings ---
 PROJECT_NODE_CLASS_MAPPINGS = {
     "ProjectLoaderDynamic": ProjectLoaderDynamic,
-    "ProjectLoaderStandard": ProjectLoaderStandard,
-    "ProjectLoaderVACE": ProjectLoaderVACE,
-    "ProjectLoaderLoRA": ProjectLoaderLoRA,
 }
 
 PROJECT_NODE_DISPLAY_NAME_MAPPINGS = {
     "ProjectLoaderDynamic": "Project Loader (Dynamic)",
-    "ProjectLoaderStandard": "Project Loader (Standard/I2V)",
-    "ProjectLoaderVACE": "Project Loader (VACE Full)",
-    "ProjectLoaderLoRA": "Project Loader (LoRAs)",
 }

tests/test_db.py

@@ -172,6 +172,25 @@ class TestSequences:
         db.delete_sequences_for_file(df_id)
         assert db.list_sequences(df_id) == []
 
+    def test_count_sequences(self, db):
+        pid = db.create_project("p1", "/p1")
+        df_id = db.create_data_file(pid, "batch", "generic")
+        assert db.count_sequences(df_id) == 0
+        db.upsert_sequence(df_id, 1, {"a": 1})
+        db.upsert_sequence(df_id, 2, {"b": 2})
+        db.upsert_sequence(df_id, 3, {"c": 3})
+        assert db.count_sequences(df_id) == 3
+
+    def test_query_total_sequences(self, db):
+        pid = db.create_project("p1", "/p1")
+        df_id = db.create_data_file(pid, "batch", "generic")
+        db.upsert_sequence(df_id, 1, {"a": 1})
+        db.upsert_sequence(df_id, 2, {"b": 2})
+        assert db.query_total_sequences("p1", "batch") == 2
+
+    def test_query_total_sequences_nonexistent(self, db):
+        assert db.query_total_sequences("nope", "nope") == 0
+
 
 # ------------------------------------------------------------------
 # History trees

tests/test_project_loader.py

@@ -6,9 +6,6 @@ import pytest
 
 from project_loader import (
     ProjectLoaderDynamic,
-    ProjectLoaderStandard,
-    ProjectLoaderVACE,
-    ProjectLoaderLoRA,
     _fetch_json,
     _fetch_data,
     _fetch_keys,
@@ -32,11 +29,23 @@ class TestFetchHelpers:
             result = _fetch_json("http://example.com/api")
         assert result == data
 
-    def test_fetch_json_failure(self):
+    def test_fetch_json_network_error(self):
-        import urllib.error
         with patch("project_loader.urllib.request.urlopen", side_effect=OSError("connection refused")):
             result = _fetch_json("http://example.com/api")
-        assert result == {}
+        assert result["error"] == "network_error"
+        assert "connection refused" in result["message"]
+
+    def test_fetch_json_http_error(self):
+        import urllib.error
+        err = urllib.error.HTTPError(
+            "http://example.com/api", 404, "Not Found", {},
+            BytesIO(json.dumps({"detail": "Project 'x' not found"}).encode())
+        )
+        with patch("project_loader.urllib.request.urlopen", side_effect=err):
+            result = _fetch_json("http://example.com/api")
+        assert result["error"] == "http_error"
+        assert result["status"] == 404
+        assert "not found" in result["message"].lower()
 
     def test_fetch_data_builds_url(self):
         data = {"prompt": "hello"}
@@ -73,18 +82,23 @@ class TestFetchHelpers:
 
 
 class TestProjectLoaderDynamic:
+    def _keys_meta(self, total=5):
+        return {"keys": [], "types": [], "total_sequences": total}
+
     def test_load_dynamic_with_keys(self):
         data = {"prompt": "hello", "seed": 42, "cfg": 1.5}
         node = ProjectLoaderDynamic()
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value=data):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys="prompt,seed,cfg"
                 )
-        assert result[0] == "hello"
+        assert result[0] == 5  # total_sequences
-        assert result[1] == 42
+        assert result[1] == "hello"
-        assert result[2] == 1.5
+        assert result[2] == 42
-        assert len(result) == MAX_DYNAMIC_OUTPUTS
+        assert result[3] == 1.5
+        assert len(result) == MAX_DYNAMIC_OUTPUTS + 1
 
     def test_load_dynamic_with_json_encoded_keys(self):
         """JSON-encoded output_keys should be parsed correctly."""
@@ -92,13 +106,14 @@ class TestProjectLoaderDynamic:
         data = {"my,key": "comma_val", "normal": "ok"}
         node = ProjectLoaderDynamic()
         keys_json = _json.dumps(["my,key", "normal"])
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value=data):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys=keys_json
                 )
-        assert result[0] == "comma_val"
+        assert result[1] == "comma_val"
-        assert result[1] == "ok"
+        assert result[2] == "ok"
 
     def test_load_dynamic_type_coercion(self):
         """output_types should coerce values to declared types."""
@@ -107,41 +122,75 @@ class TestProjectLoaderDynamic:
         node = ProjectLoaderDynamic()
         keys_json = _json.dumps(["seed", "cfg", "prompt"])
         types_json = _json.dumps(["INT", "FLOAT", "STRING"])
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value=data):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys=keys_json, output_types=types_json
                 )
-        assert result[0] == 42       # string "42" coerced to int
+        assert result[1] == 42       # string "42" coerced to int
-        assert result[1] == 1.5      # string "1.5" coerced to float
+        assert result[2] == 1.5      # string "1.5" coerced to float
-        assert result[2] == "hello"  # string stays string
+        assert result[3] == "hello"  # string stays string
 
     def test_load_dynamic_empty_keys(self):
         node = ProjectLoaderDynamic()
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value={"prompt": "hello"}):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys=""
                 )
-        assert all(v == "" for v in result)
+        # Slot 0 is total_sequences (INT), rest are empty strings
+        assert result[0] == 5
+        assert all(v == "" for v in result[1:])
 
     def test_load_dynamic_missing_key(self):
         node = ProjectLoaderDynamic()
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value={"prompt": "hello"}):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys="nonexistent"
                 )
-        assert result[0] == ""
+        assert result[1] == ""
 
     def test_load_dynamic_bool_becomes_string(self):
         node = ProjectLoaderDynamic()
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
             with patch("project_loader._fetch_data", return_value={"flag": True}):
                 result = node.load_dynamic(
                     "http://localhost:8080", "proj1", "batch_i2v", 1,
                     output_keys="flag"
                 )
-        assert result[0] == "true"
+        assert result[1] == "true"
+
+    def test_load_dynamic_returns_total_sequences(self):
+        """total_sequences should be the first output from keys metadata."""
+        node = ProjectLoaderDynamic()
+        with patch("project_loader._fetch_keys", return_value={"keys": [], "types": [], "total_sequences": 42}):
+            with patch("project_loader._fetch_data", return_value={}):
+                result = node.load_dynamic(
+                    "http://localhost:8080", "proj1", "batch_i2v", 1,
+                    output_keys=""
+                )
+        assert result[0] == 42
+
+    def test_load_dynamic_raises_on_network_error(self):
+        """Network errors from _fetch_keys should raise RuntimeError."""
+        node = ProjectLoaderDynamic()
+        error_resp = {"error": "network_error", "message": "Connection refused"}
+        with patch("project_loader._fetch_keys", return_value=error_resp):
+            with pytest.raises(RuntimeError, match="Failed to fetch project keys"):
+                node.load_dynamic("http://localhost:8080", "proj1", "batch", 1)
+
+    def test_load_dynamic_raises_on_data_fetch_error(self):
+        """Network errors from _fetch_data should raise RuntimeError."""
+        node = ProjectLoaderDynamic()
+        error_resp = {"error": "http_error", "status": 404, "message": "Sequence not found"}
+        with patch("project_loader._fetch_keys", return_value=self._keys_meta()):
+            with patch("project_loader._fetch_data", return_value=error_resp):
+                with pytest.raises(RuntimeError, match="Failed to fetch sequence data"):
+                    node.load_dynamic("http://localhost:8080", "proj1", "batch", 1)
 
     def test_input_types_has_manager_url(self):
         inputs = ProjectLoaderDynamic.INPUT_TYPES()
@@ -154,88 +203,9 @@ class TestProjectLoaderDynamic:
         assert ProjectLoaderDynamic.CATEGORY == "utils/json/project"
 
 
-class TestProjectLoaderStandard:
-    def test_load_standard(self):
-        data = {
-            "general_prompt": "hello",
-            "general_negative": "bad",
-            "current_prompt": "specific",
-            "negative": "neg",
-            "camera": "pan",
-            "flf": 0.5,
-            "seed": 42,
-            "video file path": "/v.mp4",
-            "reference image path": "/r.png",
-            "flf image path": "/f.png",
-        }
-        node = ProjectLoaderStandard()
-        with patch("project_loader._fetch_data", return_value=data):
-            result = node.load_standard("http://localhost:8080", "proj1", "batch", 1)
-        assert result == ("hello", "bad", "specific", "neg", "pan", 0.5, 42, "/v.mp4", "/r.png", "/f.png")
-
-    def test_load_standard_defaults(self):
-        node = ProjectLoaderStandard()
-        with patch("project_loader._fetch_data", return_value={}):
-            result = node.load_standard("http://localhost:8080", "proj1", "batch", 1)
-        assert result[0] == ""  # general_prompt
-        assert result[5] == 0.0  # flf
-        assert result[6] == 0  # seed
-
-
-class TestProjectLoaderVACE:
-    def test_load_vace(self):
-        data = {
-            "general_prompt": "hello",
-            "general_negative": "bad",
-            "current_prompt": "specific",
-            "negative": "neg",
-            "camera": "pan",
-            "flf": 0.5,
-            "seed": 42,
-            "frame_to_skip": 81,
-            "input_a_frames": 16,
-            "input_b_frames": 16,
-            "reference path": "/ref",
-            "reference switch": 1,
-            "vace schedule": 2,
-            "video file path": "/v.mp4",
-            "reference image path": "/r.png",
-        }
-        node = ProjectLoaderVACE()
-        with patch("project_loader._fetch_data", return_value=data):
-            result = node.load_vace("http://localhost:8080", "proj1", "batch", 1)
-        assert result[7] == 81  # frame_to_skip
-        assert result[12] == 2  # vace_schedule
-
-
-class TestProjectLoaderLoRA:
-    def test_load_loras(self):
-        data = {
-            "lora 1 high": "<lora:model1:1.0>",
-            "lora 1 low": "<lora:model1:0.5>",
-            "lora 2 high": "",
-            "lora 2 low": "",
-            "lora 3 high": "",
-            "lora 3 low": "",
-        }
-        node = ProjectLoaderLoRA()
-        with patch("project_loader._fetch_data", return_value=data):
-            result = node.load_loras("http://localhost:8080", "proj1", "batch", 1)
-        assert result[0] == "<lora:model1:1.0>"
-        assert result[1] == "<lora:model1:0.5>"
-
-    def test_load_loras_empty(self):
-        node = ProjectLoaderLoRA()
-        with patch("project_loader._fetch_data", return_value={}):
-            result = node.load_loras("http://localhost:8080", "proj1", "batch", 1)
-        assert all(v == "" for v in result)
-
-
 class TestNodeMappings:
     def test_mappings_exist(self):
         from project_loader import PROJECT_NODE_CLASS_MAPPINGS, PROJECT_NODE_DISPLAY_NAME_MAPPINGS
         assert "ProjectLoaderDynamic" in PROJECT_NODE_CLASS_MAPPINGS
-        assert "ProjectLoaderStandard" in PROJECT_NODE_CLASS_MAPPINGS
+        assert len(PROJECT_NODE_CLASS_MAPPINGS) == 1
-        assert "ProjectLoaderVACE" in PROJECT_NODE_CLASS_MAPPINGS
+        assert len(PROJECT_NODE_DISPLAY_NAME_MAPPINGS) == 1
-        assert "ProjectLoaderLoRA" in PROJECT_NODE_CLASS_MAPPINGS
-        assert len(PROJECT_NODE_DISPLAY_NAME_MAPPINGS) == 4

web/project_dynamic.js

@@ -32,18 +32,55 @@ app.registerExtension({
                 this.refreshDynamicOutputs();
             });
 
+            // Auto-refresh with 500ms debounce on widget changes
+            this._refreshTimer = null;
+            const autoRefreshWidgets = ["project_name", "file_name", "sequence_number"];
+            for (const widgetName of autoRefreshWidgets) {
+                const w = this.widgets?.find(w => w.name === widgetName);
+                if (w) {
+                    const origCallback = w.callback;
+                    const node = this;
+                    w.callback = function (...args) {
+                        origCallback?.apply(this, args);
+                        clearTimeout(node._refreshTimer);
+                        node._refreshTimer = setTimeout(() => {
+                            node.refreshDynamicOutputs();
+                        }, 500);
+                    };
+                }
+            }
+
             queueMicrotask(() => {
                 if (!this._configured) {
-                    // New node (not loading) — remove the 32 Python default outputs
+                    // New node (not loading) — remove the Python default outputs
+                    // and add only the fixed total_sequences slot
                     while (this.outputs.length > 0) {
                         this.removeOutput(0);
                     }
+                    this.addOutput("total_sequences", "INT");
                     this.setSize(this.computeSize());
                     app.graph?.setDirtyCanvas(true, true);
                 }
             });
         };
 
+        nodeType.prototype._setStatus = function (status, message) {
+            const baseTitle = "Project Loader (Dynamic)";
+            if (status === "ok") {
+                this.title = baseTitle;
+                this.color = undefined;
+                this.bgcolor = undefined;
+            } else if (status === "error") {
+                this.title = baseTitle + " - ERROR";
+                this.color = "#ff4444";
+                this.bgcolor = "#331111";
+                if (message) this.title = baseTitle + ": " + message;
+            } else if (status === "loading") {
+                this.title = baseTitle + " - Loading...";
+            }
+            app.graph?.setDirtyCanvas(true, true);
+        };
+
         nodeType.prototype.refreshDynamicOutputs = async function () {
             const urlWidget = this.widgets?.find(w => w.name === "manager_url");
             const projectWidget = this.widgets?.find(w => w.name === "project_name");
@@ -52,13 +89,20 @@ app.registerExtension({
 
             if (!urlWidget?.value || !projectWidget?.value || !fileWidget?.value) return;
 
+            this._setStatus("loading");
+
             try {
                 const resp = await api.fetchApi(
                     `/json_manager/get_project_keys?url=${encodeURIComponent(urlWidget.value)}&project=${encodeURIComponent(projectWidget.value)}&file=${encodeURIComponent(fileWidget.value)}&seq=${seqWidget?.value || 1}`
                 );
 
                 if (!resp.ok) {
-                    console.warn("[ProjectLoaderDynamic] HTTP error", resp.status, "— keeping existing outputs");
+                    let errorMsg = `HTTP ${resp.status}`;
+                    try {
+                        const errData = await resp.json();
+                        if (errData.message) errorMsg = errData.message;
+                    } catch (_) {}
+                    this._setStatus("error", errorMsg);
                     return;
                 }
 
@@ -68,7 +112,8 @@ app.registerExtension({
 
                 // If the API returned an error or missing data, keep existing outputs and links intact
                 if (data.error || !Array.isArray(keys) || !Array.isArray(types)) {
-                    console.warn("[ProjectLoaderDynamic] API error or missing data, keeping existing outputs:", data.error || "no keys/types");
+                    const errMsg = data.error ? data.message || data.error : "Missing keys/types";
+                    this._setStatus("error", errMsg);
                     return;
                 }
 
@@ -78,14 +123,20 @@ app.registerExtension({
                 const otWidget = this.widgets?.find(w => w.name === "output_types");
                 if (otWidget) otWidget.value = JSON.stringify(types);
 
-                // Build a map of current output names to slot indices
+                // Slot 0 is always total_sequences (INT) — ensure it exists
+                if (this.outputs.length === 0 || this.outputs[0].name !== "total_sequences") {
+                    this.outputs.unshift({ name: "total_sequences", type: "INT", links: null });
+                }
+                this.outputs[0].type = "INT";
+
+                // Build a map of current dynamic output names to slot indices (skip slot 0)
                 const oldSlots = {};
-                for (let i = 0; i < this.outputs.length; i++) {
+                for (let i = 1; i < this.outputs.length; i++) {
                     oldSlots[this.outputs[i].name] = i;
                 }
 
-                // Build new outputs, reusing existing slots to preserve links
+                // Build new dynamic outputs, reusing existing slots to preserve links
-                const newOutputs = [];
+                const newOutputs = [this.outputs[0]]; // Keep total_sequences at slot 0
                 for (let k = 0; k < keys.length; k++) {
                     const key = keys[k];
                     const type = types[k] || "*";
@@ -122,10 +173,12 @@ app.registerExtension({
                     }
                 }
 
+                this._setStatus("ok");
                 this.setSize(this.computeSize());
                 app.graph?.setDirtyCanvas(true, true);
             } catch (e) {
                 console.error("[ProjectLoaderDynamic] Refresh failed:", e);
+                this._setStatus("error", "Server unreachable");
             }
         };
 
@@ -158,23 +211,59 @@ app.registerExtension({
                 }
             }
 
+            // Ensure slot 0 is total_sequences (INT)
+            if (this.outputs.length === 0 || this.outputs[0].name !== "total_sequences") {
+                this.outputs.unshift({ name: "total_sequences", type: "INT", links: null });
+                // LiteGraph restores links AFTER onConfigure, so graph.links is
+                // empty here. Defer link fixup to a microtask that runs after the
+                // synchronous graph.configure() finishes (including link restoration).
+                // We must also rebuild output.links arrays because LiteGraph will
+                // place link IDs on the wrong outputs (shifted by the unshift above).
+                const node = this;
+                queueMicrotask(() => {
+                    if (!node.graph) return;
+                    // Clear all output.links — they were populated at old indices
+                    for (const output of node.outputs) {
+                        output.links = null;
+                    }
+                    // Rebuild from graph.links with corrected origin_slot (+1)
+                    for (const linkId in node.graph.links) {
+                        const link = node.graph.links[linkId];
+                        if (!link || link.origin_id !== node.id) continue;
+                        link.origin_slot += 1;
+                        const output = node.outputs[link.origin_slot];
+                        if (output) {
+                            if (!output.links) output.links = [];
+                            output.links.push(link.id);
+                        }
+                    }
+                    app.graph?.setDirtyCanvas(true, true);
+                });
+            }
+            this.outputs[0].type = "INT";
+            this.outputs[0].name = "total_sequences";
+
             if (keys.length > 0) {
                 // On load, LiteGraph already restored serialized outputs with links.
-                // Rename and set types to match stored state (preserves links).
+                // Dynamic outputs start at slot 1. Rename and set types to match stored state.
-                for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
+                for (let i = 0; i < keys.length; i++) {
-                    this.outputs[i].name = keys[i];
+                    const slotIdx = i + 1; // offset by 1 for total_sequences
-                    if (types[i]) this.outputs[i].type = types[i];
+                    if (slotIdx < this.outputs.length) {
+                        this.outputs[slotIdx].name = keys[i];
+                        if (types[i]) this.outputs[slotIdx].type = types[i];
+                    }
                 }
 
-                // Remove any extra outputs beyond the key count
+                // Remove any extra outputs beyond keys + total_sequences
-                while (this.outputs.length > keys.length) {
+                while (this.outputs.length > keys.length + 1) {
                     this.removeOutput(this.outputs.length - 1);
                 }
-            } else if (this.outputs.length > 0) {
+            } else if (this.outputs.length > 1) {
-                // Widget values empty but serialized outputs exist — sync widgets
+                // Widget values empty but serialized dynamic outputs exist — sync widgets
-                // from the outputs LiteGraph already restored (fallback).
+                // from the outputs LiteGraph already restored (fallback, skip slot 0).
-                if (okWidget) okWidget.value = JSON.stringify(this.outputs.map(o => o.name));
+                const dynamicOutputs = this.outputs.slice(1);
-                if (otWidget) otWidget.value = JSON.stringify(this.outputs.map(o => o.type));
+                if (okWidget) okWidget.value = JSON.stringify(dynamicOutputs.map(o => o.name));
+                if (otWidget) otWidget.value = JSON.stringify(dynamicOutputs.map(o => o.type));
             }
 
             this.setSize(this.computeSize());