test: remove redundant coverage and consolidate happy paths

Support image, audio, or combined distributed collection with guarded audio-only worker, master, endpoint, preview, and delegate-only paths.

README.md

@@ -147,7 +147,7 @@ Accelerate Ultimate SD Upscaler by distributing video tiles across multiple work
 Control your distributed cluster programmatically without opening the browser.
 
 * **Endpoint:** `POST /distributed/queue`
-* **Functionality:** Accepts a standard ComfyUI workflow JSON, automatically distributes it to available workers, and returns the execution ID.
+* **Functionality:** Accepts a ComfyUI API-format prompt, dispatches it to the requested reachable workers, and returns the master `prompt_id`.
 * **Documentation:** [See API Examples & Scripts](https://github.com/robertvoy/ComfyUI-Distributed/blob/main/docs/comfyui-distributed-api.md)
 
 > **⚠️ Security Warning:** Do not expose your ComfyUI port to the public internet. If you need remote access, run ComfyUI behind a secure proxy (like Cloudflare or a VPN).
@@ -175,7 +175,7 @@ Use **Distributed Value** when you want per-worker overrides (for example, diffe
 | **Distributed Value** | Outputs per-worker override values with fallback to default |
 | **Ultimate SD Upscale Distributed** | Distributes upscale tiles across workers |
 | **Image Batch Divider** | Splits image batches for multi-GPU output |
-| **Audio Batch Divider** | Splits audio batches for multi-GPU output |
+| **Audio Segment Divider** | Splits an audio waveform into up to ten sequential time segments |
 | **Distributed Model Name** | Passes model paths to workers, enabling workflows to use models not present on the master in orchestrator-only mode |
 | **Distributed Empty Image** | Produces an empty IMAGE batch used when the master delegates all work |
 

api/job_routes.py

@@ -295,17 +295,24 @@ async def job_complete_endpoint(request):
             errors.append("worker_id: expected non-empty string")
         if not isinstance(batch_idx, int) or batch_idx < 0:
             errors.append("batch_idx: expected non-negative integer")
-        if not isinstance(image_payload, str) or not image_payload.strip():
+        image_provided = image_payload is not None
+        audio_provided = audio_payload is not None
+        if not image_provided and not audio_provided:
+            errors.append("expected at least one of image or audio")
+        if image_provided and (not isinstance(image_payload, str) or not image_payload.strip()):
             errors.append("image: expected non-empty base64 PNG string")
-        if audio_payload is not None and not isinstance(audio_payload, dict):
+        if audio_provided and not isinstance(audio_payload, dict):
             errors.append("audio: expected object when provided")
         if not isinstance(is_last, bool):
             errors.append("is_last: expected boolean")
         if errors:
             return await handle_api_error(request, errors, 400)
 
-        tensor = _decode_canonical_png_tensor(image_payload)
+        try:
-        decoded_audio = _decode_audio_payload(audio_payload) if audio_payload is not None else None
+            tensor = _decode_canonical_png_tensor(image_payload) if image_provided else None
+            decoded_audio = _decode_audio_payload(audio_payload) if audio_provided else None
+        except ValueError as exc:
+            return await handle_api_error(request, exc, 400)
         multi_job_id = job_id.strip()
         worker_id = worker_id.strip()
 

api/orchestration/prompt_transform.py

@@ -125,6 +125,209 @@ def _find_upstream_nodes(prompt_obj, start_ids):
     return connected
 
 
+_DELEGATE_MASTER_RETAINED_UPSTREAM_CLASSES = {
+    "PrimitiveBoolean",
+    "PrimitiveFloat",
+    "PrimitiveInt",
+    "PrimitiveNode",
+    "PrimitiveString",
+}
+
+_DELEGATE_MASTER_ALWAYS_RETAINED_UPSTREAM_CLASSES = {
+    "LoadImage",
+}
+
+_DELEGATE_MASTER_SAFE_SCALAR_TYPES = {"BOOLEAN", "FLOAT", "INT", "STRING"}
+_DELEGATE_MASTER_SAFE_LIST_TYPES = {"LIST"}
+
+# ComfyUI 0.23 exposes CreateList via the newer schema API rather than the
+# legacy RETURN_TYPES/INPUT_TYPES attributes. Treat it as a safe config utility
+# only after its connected inputs recursively prove safe.
+_DELEGATE_MASTER_SAFE_DYNAMIC_CONFIG_OUTPUT_CLASSES = {"CreateList"}
+_DELEGATE_MASTER_SAFE_DYNAMIC_CONFIG_INPUT_PREFIXES = {
+    "CreateList": ("inputs.",),
+}
+
+# Test hook. At runtime this stays None and the ComfyUI node registry is loaded lazily.
+_DELEGATE_MASTER_NODE_CLASS_MAPPINGS = None
+
+
+def _get_delegate_master_node_class_mappings():
+    """Return ComfyUI node-class mappings when available."""
+    if _DELEGATE_MASTER_NODE_CLASS_MAPPINGS is not None:
+        return _DELEGATE_MASTER_NODE_CLASS_MAPPINGS
+    try:
+        import nodes as comfy_nodes  # type: ignore
+    except Exception:  # pragma: no cover - depends on ComfyUI runtime imports
+        return {}
+    return getattr(comfy_nodes, "NODE_CLASS_MAPPINGS", {}) or {}
+
+
+def _get_delegate_master_node_class(class_type):
+    mappings = _get_delegate_master_node_class_mappings()
+    return mappings.get(class_type) if isinstance(mappings, dict) else None
+
+
+def _normalize_delegate_master_return_type(return_type):
+    if return_type is None:
+        return ""
+    return str(return_type).strip().upper()
+
+
+def _delegate_master_type_is_safe_scalar(type_name):
+    return type_name in _DELEGATE_MASTER_SAFE_SCALAR_TYPES
+
+
+def _delegate_master_type_is_safe_config(type_name):
+    return _delegate_master_type_is_safe_scalar(type_name) or type_name in _DELEGATE_MASTER_SAFE_LIST_TYPES
+
+
+def _delegate_master_output_is_safe_scalar(class_type, output_index):
+    """Return True when a registered node output is lightweight config data."""
+    if class_type in _DELEGATE_MASTER_SAFE_DYNAMIC_CONFIG_OUTPUT_CLASSES:
+        return True
+    node_class = _get_delegate_master_node_class(class_type)
+    return_types = getattr(node_class, "RETURN_TYPES", ()) if node_class is not None else ()
+    try:
+        output_type = return_types[int(output_index)]
+    except (IndexError, TypeError, ValueError):
+        return False
+    return _delegate_master_type_is_safe_config(_normalize_delegate_master_return_type(output_type))
+
+
+def _get_delegate_master_input_types(class_type):
+    node_class = _get_delegate_master_node_class(class_type)
+    input_types = getattr(node_class, "INPUT_TYPES", None) if node_class is not None else None
+    if callable(input_types):
+        try:
+            input_types = input_types()
+        except TypeError:
+            return {}
+    return input_types if isinstance(input_types, dict) else {}
+
+
+def _normalize_delegate_master_input_type(input_spec):
+    if isinstance(input_spec, (list, tuple)) and input_spec:
+        return _normalize_delegate_master_return_type(input_spec[0])
+    return _normalize_delegate_master_return_type(input_spec)
+
+
+def _delegate_master_input_is_safe_scalar(class_type, input_name):
+    """Return True when a registered downstream input expects config data."""
+    for prefix in _DELEGATE_MASTER_SAFE_DYNAMIC_CONFIG_INPUT_PREFIXES.get(class_type, ()):
+        if input_name.startswith(prefix):
+            return True
+    input_types = _get_delegate_master_input_types(class_type)
+    for section_name in ("required", "optional"):
+        section = input_types.get(section_name, {})
+        if isinstance(section, dict) and input_name in section:
+            input_type = _normalize_delegate_master_input_type(section[input_name])
+            return _delegate_master_type_is_safe_config(input_type)
+    return False
+
+
+def _is_delegate_master_always_retained_upstream_node(node):
+    if not isinstance(node, dict):
+        return False
+    class_type = node.get("class_type")
+    return isinstance(class_type, str) and class_type in _DELEGATE_MASTER_ALWAYS_RETAINED_UPSTREAM_CLASSES
+
+
+def _is_delegate_master_retained_upstream_node(node, output_index=0):
+    """Return True for lightweight upstream nodes safe to keep on the master."""
+    if not isinstance(node, dict):
+        return False
+    class_type = node.get("class_type")
+    if not isinstance(class_type, str):
+        return False
+    return (
+        class_type in _DELEGATE_MASTER_RETAINED_UPSTREAM_CLASSES
+        or class_type.startswith("Primitive")
+        or _delegate_master_output_is_safe_scalar(class_type, output_index)
+    )
+
+
+def _collect_delegate_master_retained_upstream_branch(
+    prompt_obj,
+    node_id,
+    output_index,
+    memo,
+    visiting,
+):
+    """Return safe retained branch nodes, or None when the branch is not safe."""
+    node_id = str(node_id)
+    cache_key = (node_id, output_index)
+    if cache_key in memo:
+        cached = memo[cache_key]
+        return None if cached is None else set(cached)
+    if cache_key in visiting:
+        memo[cache_key] = None
+        return None
+
+    node = prompt_obj.get(node_id)
+    if not _is_delegate_master_retained_upstream_node(node, output_index):
+        memo[cache_key] = None
+        return None
+
+    visiting.add(cache_key)
+    retained = {node_id}
+    inputs = node.get("inputs", {}) if isinstance(node, dict) else {}
+    class_type = node.get("class_type") if isinstance(node, dict) else None
+    for input_name, value in inputs.items():
+        if not (isinstance(value, list) and len(value) == 2):
+            continue
+        if not _delegate_master_input_is_safe_scalar(class_type, input_name):
+            visiting.remove(cache_key)
+            memo[cache_key] = None
+            return None
+        source_id = str(value[0])
+        branch = _collect_delegate_master_retained_upstream_branch(
+            prompt_obj,
+            source_id,
+            value[1],
+            memo,
+            visiting,
+        )
+        if branch is None:
+            visiting.remove(cache_key)
+            memo[cache_key] = None
+            return None
+        retained.update(branch)
+
+    visiting.remove(cache_key)
+    memo[cache_key] = frozenset(retained)
+    return retained
+
+
+def _find_delegate_master_retained_upstream_nodes(prompt_obj, start_ids):
+    """Return lightweight upstream nodes needed by kept delegate-master nodes."""
+    connected = set()
+    memo = {}
+    for node_id in start_ids:
+        node = prompt_obj.get(str(node_id)) or {}
+        inputs = node.get("inputs", {})
+        class_type = node.get("class_type") if isinstance(node, dict) else None
+        for input_name, value in inputs.items():
+            if not (isinstance(value, list) and len(value) == 2):
+                continue
+            source_node = prompt_obj.get(str(value[0]))
+            if _is_delegate_master_always_retained_upstream_node(source_node):
+                connected.add(str(value[0]))
+                continue
+            if not _delegate_master_input_is_safe_scalar(class_type, input_name):
+                continue
+            branch = _collect_delegate_master_retained_upstream_branch(
+                prompt_obj,
+                value[0],
+                value[1],
+                memo,
+                set(),
+            )
+            if branch is not None:
+                connected.update(branch)
+    return connected
+
+
 def prune_prompt_for_worker(prompt_obj):
     """Prune worker prompt to distributed nodes and their upstream dependencies."""
     collector_ids = find_nodes_by_class(prompt_obj, "DistributedCollector")
@@ -148,16 +351,33 @@ def prune_prompt_for_worker(prompt_obj):
         downstream = _find_downstream_nodes(prompt_obj, [dist_id])
         has_removed_downstream = any(node_id != dist_id for node_id in downstream)
         if has_removed_downstream:
-            preview_id = next_id()
+            original_node = prompt_obj.get(str(dist_id), {})
-            pruned_prompt[preview_id] = {
+            class_type = original_node.get("class_type")
-                "inputs": {
+            inputs = original_node.get("inputs", {})
-                    "images": [dist_id, 0],
+            image_connected = class_type != "DistributedCollector" or (
-                },
+                isinstance(inputs.get("images"), list)
-                "class_type": "PreviewImage",
+                and len(inputs["images"]) == 2
-                "_meta": {
+            )
-                    "title": "Preview Image (auto-added)",
+            audio_connected = (
-                },
+                class_type == "DistributedCollector"
-            }
+                and isinstance(inputs.get("audio"), list)
+                and len(inputs["audio"]) == 2
+            )
+
+            if image_connected:
+                preview_id = next_id()
+                pruned_prompt[preview_id] = {
+                    "inputs": {"images": [dist_id, 0]},
+                    "class_type": "PreviewImage",
+                    "_meta": {"title": "Preview Image (auto-added)"},
+                }
+            elif audio_connected:
+                preview_id = next_id()
+                pruned_prompt[preview_id] = {
+                    "inputs": {"audio": [dist_id, 1]},
+                    "class_type": "PreviewAudio",
+                    "_meta": {"title": "Preview Audio (auto-added)"},
+                }
 
     return pruned_prompt
 
@@ -167,6 +387,9 @@ def prepare_delegate_master_prompt(prompt_obj, collector_ids):
     downstream = _find_downstream_nodes(prompt_obj, collector_ids)
     nodes_to_keep = set(collector_ids)
     nodes_to_keep.update(downstream)
+    nodes_to_keep.update(
+        _find_delegate_master_retained_upstream_nodes(prompt_obj, nodes_to_keep)
+    )
 
     pruned_prompt = {}
     for node_id in nodes_to_keep:
@@ -194,6 +417,10 @@ def prepare_delegate_master_prompt(prompt_obj, collector_ids):
         collector_entry = pruned_prompt.get(collector_id)
         if not collector_entry:
             continue
+        original_inputs = (prompt_obj.get(collector_id) or {}).get("inputs", {})
+        original_images = original_inputs.get("images")
+        if not (isinstance(original_images, list) and len(original_images) == 2):
+            continue
         placeholder_id = next_id()
         pruned_prompt[placeholder_id] = {
             "class_type": "DistributedEmptyImage",

docs/comfyui-distributed-api.md

@@ -19,8 +19,8 @@ This document describes the **public HTTP API** added to ComfyUI-Distributed to
 - `POST /distributed/queue` — queues a workflow using the same distributed orchestration rules as the UI:
   - Detects distributed nodes in the prompt (`DistributedCollector`, `UltimateSDUpscaleDistributed`).
   - Resolves enabled/selected workers.
-  - Pings workers (`GET /prompt`) to include only reachable ones.
+  - Probes and dispatches workers through `/distributed/worker_ws` by default.
-  - Dispatches the workflow to workers (`POST /prompt`).
+  - If `settings.websocket_orchestration=false`, probes with `GET /prompt` and dispatches with `POST /prompt` instead.
   - Queues the master workflow in ComfyUI’s prompt queue.
   - If any `DistributedCollector` has `load_balance=true`, selects one least-busy participant for this run.
 
@@ -61,7 +61,8 @@ Queue a workflow for distributed execution.
 #### Fields
 
 - `prompt` (required unless `workflow.prompt` is present, object)
-  - The ComfyUI prompt/workflow graph, same shape as used by `POST /prompt`.
+  - A complete ComfyUI API-format prompt graph, using the same shape as `POST /prompt`.
+  - This is not the normal visual workflow export from the ComfyUI editor.
 - `workflow` (optional, object)
   - Workflow metadata that ComfyUI normally stores in `extra_pnginfo.workflow`.
   - If you don’t care about UI metadata, you can omit it.
@@ -123,10 +124,14 @@ $cfg.workers | Select-Object id,name,enabled,host,port,type | Format-Table -Auto
 
 ## Worker requirements (important)
 
-For a worker to participate, it must be reachable from the master:
+For a worker to participate, it must be reachable from the master. By default:
+
+- WebSocket probe and dispatch: `<worker-base>/distributed/worker_ws` must accept the connection.
+
+If `settings.websocket_orchestration=false`:
 
 - Health check: `GET <worker-base>/prompt` must return HTTP 200.
-- Dispatch: `POST <worker-base>/prompt` must accept the workflow.
+- Dispatch: `POST <worker-base>/prompt` must accept the prompt.
 
 Also, for collector-based flows:
 
@@ -201,7 +206,7 @@ Proxy endpoint on master that fetches logs from a configured remote/cloud worker
 
 ## Examples
 
-### 1) Minimal `curl`
+### 1) Minimal `curl` request envelope
 
 ```bash
 curl -X POST "http://127.0.0.1:8188/distributed/queue" \
@@ -209,18 +214,23 @@ curl -X POST "http://127.0.0.1:8188/distributed/queue" \
   -d @payload.json
 ```
 
-Where `payload.json` contains at least:
+`payload.json` must contain a complete ComfyUI API-format prompt. The abbreviated envelope below illustrates the request shape but is not directly executable:
 
 ```json
 {
   "prompt": {
-    "1": {"class_type": "KSampler", "inputs": {} }
+    "<node_id>": {
+      "class_type": "<node class>",
+      "inputs": {"<required_input>": "<value or connection>"}
+    }
   },
   "enabled_worker_ids": [],
   "client_id": "external-client"
 }
 ```
 
+Export or construct a valid API-format prompt with all required node inputs and at least one output node before submitting it.
+
 ### 2) Python (`requests`)
 
 ```python

docs/worker-setup-guides.md

@@ -79,7 +79,7 @@ The master can either contribute GPU work or stay in **orchestrator-only** mode:
 📺 [Watch Tutorial](https://www.youtube.com/watch?v=wxKKWMQhYTk)
 
 **On Runpod:**
-> If using your own template, make sure you launch ComfyUI with the `--enable-cors-header` argument and you `git clone ComfyUI-Distributed` into custom_nodes. ⚠️ **Required!**
+> If using your own template, launch ComfyUI with `--listen --enable-cors-header` and clone `ComfyUI-Distributed` into `custom_nodes`. ⚠️ **Required!**
 
 1. Register a [Runpod](https://get.runpod.io/0bw29uf3ug0p) account.
 2. On Runpod, go to Storage > New Network Volume and create a volume that will store the models you need. Start with 40 GB, you can always add more later. Learn more [about Network Volumes](https://docs.runpod.io/pods/storage/create-network-volumes).
@@ -92,7 +92,7 @@ The master can either contribute GPU work or stay in **orchestrator-only** mode:
 	- SAGE_ATTENTION: optional optimisation (set to true/false)
 5. Deploy your pod.
 6. Connect to your pod using JupyterLabs. This gives us access to the pod's file system.
-7. Download models into /workspaces/ComfyUI/models/ (these will remain on your network drive even after you terminate the pod). Example commands below:
+7. Download models into `/workspace/ComfyUI/models/` (these will remain on your network drive even after you terminate the pod). Example commands below:
 ```
 # Download from CivitAI
 comfy model download --url https://civitai.com/api/download/models/1759168 --relative-path /workspace/ComfyUI/models/checkpoints --set-civitai-api-token $CIVITAI_API_TOKEN

nodes/__init__.py

@@ -26,6 +26,6 @@ NODE_DISPLAY_NAME_MAPPINGS = {
     "DistributedModelName": "Distributed Model Name",
     "DistributedValue": "Distributed Value",
     "ImageBatchDivider": "Image Batch Divider",
-    "AudioBatchDivider": "Audio Batch Divider",
+    "AudioBatchDivider": "Audio Segment Divider",
     "DistributedEmptyImage": "Distributed Empty Image",
 }

nodes/collector.py

@@ -29,7 +29,6 @@ class DistributedCollectorNode:
     def INPUT_TYPES(s):
         return {
             "required": {
-                "images": ("IMAGE",),
                 "load_balance": (
                     "BOOLEAN",
                     {
@@ -38,7 +37,10 @@ class DistributedCollectorNode:
                     },
                 ),
             },
-            "optional": { "audio": ("AUDIO",) },
+            "optional": {
+                "images": ("IMAGE",),
+                "audio": ("AUDIO",),
+            },
             "hidden": {
                 "multi_job_id": ("STRING", {"default": ""}),
                 "is_worker": ("BOOLEAN", {"default": False}),
@@ -102,8 +104,9 @@ class DistributedCollectorNode:
             return None
         return {"waveform": torch.cat(waveforms, dim=-1), "sample_rate": sample_rate}
 
-    def run(self, images, load_balance=False, audio=None, multi_job_id="", is_worker=False, master_url="", enabled_worker_ids="[]", worker_batch_size=1, worker_id="", pass_through=False, delegate_only=False):
+    def run(self, images=None, load_balance=False, audio=None, multi_job_id="", is_worker=False, master_url="", enabled_worker_ids="[]", worker_batch_size=1, worker_id="", pass_through=False, delegate_only=False):
-        images = self._normalize_images_input(images)
+        if images is not None:
+            images = self._normalize_images_input(images)
         audio = self._normalize_audio_input(audio)
         load_balance = self._unwrap_list_input(load_balance)
         multi_job_id = self._unwrap_list_input(multi_job_id)
@@ -115,6 +118,14 @@ class DistributedCollectorNode:
         pass_through = self._unwrap_list_input(pass_through)
         delegate_only = self._unwrap_list_input(delegate_only)
 
+        remote_only_master = (
+            bool(multi_job_id)
+            and not is_worker
+            and (delegate_only or is_master_delegate_only())
+        )
+        if images is None and audio is None and not remote_only_master:
+            raise ValueError("DistributedCollector requires at least one image or audio input")
+
         # Create empty audio if not provided
         empty_audio = {"waveform": torch.zeros(1, 2, 1), "sample_rate": 44100}
 
@@ -141,41 +152,56 @@ class DistributedCollectorNode:
         return result
 
     async def send_batch_to_master(self, image_batch, audio, multi_job_id, master_url, worker_id):
-        """Send image batch to master via canonical JSON envelopes."""
+        """Send an image batch, optionally with audio, or an audio-only completion."""
-        batch_size = image_batch.shape[0]
-        if batch_size == 0:
-            return
-
         encoded_audio = encode_audio_payload(audio)
-
         session = await get_client_session()
         url = f"{master_url}/distributed/job_complete"
-        for batch_idx in range(batch_size):
-            img = tensor_to_pil(image_batch[batch_idx:batch_idx+1], 0)
-            byte_io = io.BytesIO()
-            img.save(byte_io, format='PNG', compress_level=0)
-            encoded_image = base64.b64encode(byte_io.getvalue()).decode('utf-8')
-            payload = {
-                "job_id": str(multi_job_id),
-                "worker_id": str(worker_id),
-                "batch_idx": int(batch_idx),
-                "image": f"data:image/png;base64,{encoded_image}",
-                "is_last": bool(batch_idx == batch_size - 1),
-            }
-            if payload["is_last"] and encoded_audio is not None:
-                payload["audio"] = encoded_audio
 
+        payloads = []
+        batch_size = 0 if image_batch is None else image_batch.shape[0]
+        if batch_size == 0:
+            if encoded_audio is None:
+                raise ValueError("Worker completion requires image or audio data")
+            payloads.append(
+                {
+                    "job_id": str(multi_job_id),
+                    "worker_id": str(worker_id),
+                    "batch_idx": 0,
+                    "audio": encoded_audio,
+                    "is_last": True,
+                }
+            )
+        else:
+            for batch_idx in range(batch_size):
+                img = tensor_to_pil(image_batch[batch_idx:batch_idx+1], 0)
+                byte_io = io.BytesIO()
+                img.save(byte_io, format='PNG', compress_level=0)
+                encoded_image = base64.b64encode(byte_io.getvalue()).decode('utf-8')
+                payload = {
+                    "job_id": str(multi_job_id),
+                    "worker_id": str(worker_id),
+                    "batch_idx": int(batch_idx),
+                    "image": f"data:image/png;base64,{encoded_image}",
+                    "is_last": bool(batch_idx == batch_size - 1),
+                }
+                if payload["is_last"] and encoded_audio is not None:
+                    payload["audio"] = encoded_audio
+                payloads.append(payload)
+
+        for payload in payloads:
+            timeout_seconds = 60 if "image" in payload else 600
             try:
                 async with session.post(
                     url,
                     json=payload,
-                    timeout=aiohttp.ClientTimeout(total=60),
+                    timeout=aiohttp.ClientTimeout(total=timeout_seconds),
                 ) as response:
                     response.raise_for_status()
             except Exception as e:
-                log(f"Worker - Failed to send canonical image envelope to master: {e}")
+                media_type = "image/audio" if "image" in payload else "audio-only"
+                log(f"Worker - Failed to send canonical {media_type} envelope to master: {e}")
                 debug_log(f"Worker - Full error details: URL={url}")
-                raise  # Re-raise to handle at caller level
+                raise
 
     def _combine_audio(self, master_audio, worker_audio, empty_audio, worker_order=None):
         """Combine audio from master and workers into a single audio output.
@@ -257,8 +283,8 @@ class DistributedCollectorNode:
         images_on_cpu,
         delegate_mode: bool,
         fallback_images,
-    ) -> torch.Tensor:
+    ):
-        """Assemble final tensor: master first, then workers in enabled order."""
+        """Assemble final tensor, or return None when the job contains only audio."""
         ordered_tensors = []
         if not delegate_mode and images_on_cpu is not None:
             for i in range(master_batch_size):
@@ -289,15 +315,15 @@ class DistributedCollectorNode:
 
         if cpu_tensors:
             return ensure_contiguous(torch.cat(cpu_tensors, dim=0))
-        elif fallback_images is not None:
+        if fallback_images is not None:
             return ensure_contiguous(fallback_images)
-        else:
+        return None
-            raise ValueError("No image data collected from master or workers")
 
     async def execute(self, images, audio, load_balance=False, multi_job_id="", is_worker=False, master_url="", enabled_worker_ids="[]", worker_batch_size=1, worker_id="", delegate_only=False):
         if is_worker:
             # Worker mode: send images and audio to master in a single batch
-            debug_log(f"Worker - Job {multi_job_id} complete. Sending {images.shape[0]} image(s) to master")
+            image_count = 0 if images is None else images.shape[0]
+            debug_log(f"Worker - Job {multi_job_id} complete. Sending {image_count} image(s) to master")
             await self.send_batch_to_master(images, audio, multi_job_id, master_url, worker_id)
             return (images, audio if audio is not None else self.EMPTY_AUDIO)
         else:
@@ -332,14 +358,15 @@ class DistributedCollectorNode:
                 master_audio = None
                 debug_log(f"Master - Job {multi_job_id}: Delegate-only mode enabled, collecting exclusively from {num_workers} workers")
             else:
-                images_on_cpu = images.cpu()
+                if images is None:
-                master_batch_size = images.shape[0]
+                    images_on_cpu = None
+                    master_batch_size = 0
+                else:
+                    images_on_cpu = ensure_contiguous(images.cpu())
+                    master_batch_size = images.shape[0]
                 master_audio = audio  # Keep master's audio for later
                 debug_log(f"Master - Job {multi_job_id}: Master has {master_batch_size} images, collecting from {num_workers} workers...")
 
-                # Ensure master images are contiguous
-                images_on_cpu = ensure_contiguous(images_on_cpu)
-
 
             # Initialize storage for collected images and audio
             worker_images = {}  # Dict to store images by worker_id and index
@@ -511,18 +538,19 @@ class DistributedCollectorNode:
                 if multi_job_id in prompt_server.distributed_pending_jobs:
                     del prompt_server.distributed_pending_jobs[multi_job_id]
 
+            combined_audio = self._combine_audio(master_audio, worker_audio, self.EMPTY_AUDIO, enabled_workers)
             try:
                 combined = self._reorder_and_combine_tensors(
                     worker_images, enabled_workers, master_batch_size, images_on_cpu, delegate_mode, images
                 )
-                debug_log(f"Master - Job {multi_job_id} complete. Combined {combined.shape[0]} images total "
+                if combined is None:
-                          f"(master: {master_batch_size}, workers: {combined.shape[0] - master_batch_size})")
+                    debug_log(f"Master - Job {multi_job_id} complete with audio only")
-
+                else:
-                # Combine audio from master and workers
+                    debug_log(f"Master - Job {multi_job_id} complete. Combined {combined.shape[0]} images total "
-                combined_audio = self._combine_audio(master_audio, worker_audio, self.EMPTY_AUDIO, enabled_workers)
+                              f"(master: {master_batch_size}, workers: {combined.shape[0] - master_batch_size})")
 
                 return (combined, combined_audio)
             except Exception as e:
                 log(f"Master - Error combining images: {e}")
-                # Return just the master images as fallback
+                # Preserve collected audio even when image assembly fails.
-                return (images, audio if audio is not None else self.EMPTY_AUDIO)
+                return (images, combined_audio)

nodes/distributed_upscale.py

@@ -56,22 +56,22 @@ class UltimateSDUpscaleDistributed(
     """
     Distributed version of Ultimate SD Upscale (No Upscale).
     
-    Supports three processing modes:
+    Supports two currently selected processing modes:
     1. Single GPU: No workers available, process everything locally
-    2. Static Mode: Small batches, distributes tiles across workers (flattened)
+    2. Distributed tile queue: Workers pull tiles from a shared queue
-    3. Dynamic Mode: Large batches, assigns whole images to workers dynamically
     
     Features:
-    - Multi-mode batch handling for efficient video/image upscaling
+    - Tile-based batch handling for video/image upscaling
     - Tiled VAE support for memory efficiency
-    - Dynamic load balancing for large batches
+    - Shared work queue so faster workers can process more tiles
     - Backward compatible with single-image workflows
     
     Environment Variables:
     - COMFYUI_MAX_BATCH: Chunk size for tile sending (default 20)
     - COMFYUI_MAX_PAYLOAD_SIZE: Max API payload bytes (default 50MB)
     
-    Threshold: dynamic_threshold input controls mode switch (default 8)
+    The hidden dynamic_threshold input is retained for workflow compatibility but
+    does not affect the current mode-selection policy.
     """
 
     def __init__(self):

nodes/utilities.py

@@ -269,7 +269,7 @@ class ImageBatchDivider:
 
 
 class AudioBatchDivider:
-    """Divides an audio waveform into multiple parts along the time/samples dimension."""
+    """Divides an audio waveform into sequential segments along the time dimension."""
 
     @classmethod
     def INPUT_TYPES(s):
@@ -282,7 +282,7 @@ class AudioBatchDivider:
                     "max": 10,
                     "step": 1,
                     "display": "number",
-                    "tooltip": "Number of parts to divide the audio into"
+                    "tooltip": "Number of sequential time segments to create"
                 }),
             }
         }

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "ComfyUI-Distributed"
 description = "ComfyUI extension that enables multi-GPU processing locally, remotely and in the cloud"
-version = "1.4.4"
+version = "1.4.7"
 license = {file = "LICENSE"}
 dependencies  = []
 

tests/api/test_distributed_queue.py

@@ -302,6 +302,77 @@ class JobCompleteAudioPayloadTests(unittest.IsolatedAsyncioTestCase):
         self.assertEqual(queued["audio"]["sample_rate"], 44100)
         self.assertEqual(tuple(queued["audio"]["waveform"].shape), (1, 2, 4))
 
+    async def test_job_complete_accepts_audio_without_image(self):
+        queue = asyncio.Queue()
+        job_routes.prompt_server.distributed_jobs_lock = asyncio.Lock()
+        job_routes.prompt_server.distributed_pending_jobs = {"audio-only-job": queue}
+        request = _FakeRequest(
+            {
+                "job_id": "audio-only-job",
+                "worker_id": "worker-1",
+                "batch_idx": 0,
+                "audio": self._encoded_audio_payload(),
+                "is_last": True,
+            }
+        )
+
+        with patch.object(job_routes, "_decode_canonical_png_tensor") as decode_image:
+            response = await job_routes.job_complete_endpoint(request)
+
+        self.assertEqual(response.status, 200)
+        decode_image.assert_not_called()
+        queued = await queue.get()
+        self.assertIsNone(queued["tensor"])
+        self.assertEqual(queued["audio"]["sample_rate"], 44100)
+
+    async def test_job_complete_rejects_payload_without_image_or_audio(self):
+        request = _FakeRequest(
+            {
+                "job_id": "job-1",
+                "worker_id": "worker-1",
+                "batch_idx": 0,
+                "is_last": True,
+            }
+        )
+
+        response = await job_routes.job_complete_endpoint(request)
+
+        self.assertEqual(response.status, 400)
+        self.assertIn("image or audio", response.payload.get("message", "").lower())
+
+    async def test_job_complete_rejects_invalid_image_even_when_audio_is_present(self):
+        request = _FakeRequest(
+            {
+                "job_id": "job-1",
+                "worker_id": "worker-1",
+                "batch_idx": 0,
+                "image": 123,
+                "audio": self._encoded_audio_payload(),
+                "is_last": True,
+            }
+        )
+
+        response = await job_routes.job_complete_endpoint(request)
+
+        self.assertEqual(response.status, 400)
+        self.assertIn("image", response.payload.get("message", "").lower())
+
+    async def test_job_complete_returns_400_for_malformed_audio(self):
+        request = _FakeRequest(
+            {
+                "job_id": "job-1",
+                "worker_id": "worker-1",
+                "batch_idx": 0,
+                "audio": {"data": "AAAA", "shape": [1, 2], "dtype": "float32"},
+                "is_last": True,
+            }
+        )
+
+        response = await job_routes.job_complete_endpoint(request)
+
+        self.assertEqual(response.status, 400)
+        self.assertIn("audio.shape", response.payload.get("message", "").lower())
+
     def test_decode_audio_payload_rejects_bad_shape(self):
         bad = {
             "sample_rate": 44100,

tests/api/test_media_sync.py

@@ -164,26 +164,11 @@ class ConvertPathsForPlatformTests(unittest.TestCase):
 # ---------------------------------------------------------------------------
 
 class FindMediaReferencesTests(unittest.TestCase):
-    def test_finds_image_input(self):
-        prompt = {"1": {"class_type": "LoadImage", "inputs": {"image": "photo.png"}}}
-        refs = ms._find_media_references(prompt)
-        self.assertIn("photo.png", refs)
-
-    def test_finds_video_input(self):
-        prompt = {"1": {"class_type": "LoadVideo", "inputs": {"video": "clip.mp4"}}}
-        refs = ms._find_media_references(prompt)
-        self.assertIn("clip.mp4", refs)
-
     def test_finds_file_input_for_load_video(self):
         prompt = {"1": {"class_type": "LoadVideo", "inputs": {"file": "1 - Copy.mp4"}}}
         refs = ms._find_media_references(prompt)
         self.assertIn("1 - Copy.mp4", refs)
 
-    def test_finds_audio_input(self):
-        prompt = {"1": {"class_type": "LoadAudio", "inputs": {"audio": "track.wav"}}}
-        refs = ms._find_media_references(prompt)
-        self.assertIn("track.wav", refs)
-
     def test_strips_annotation_suffix(self):
         prompt = {"1": {"class_type": "LoadImage", "inputs": {"image": "photo.jpg [abc123]"}}}
         refs = ms._find_media_references(prompt)

tests/test_collector_list_inputs.py

@@ -124,6 +124,49 @@ def test_collector_opts_into_comfyui_list_inputs():
     assert collector.INPUT_IS_LIST is True
 
 
+def test_collector_exposes_images_as_optional_input():
+    input_types = _load_collector_module().DistributedCollectorNode.INPUT_TYPES()
+
+    assert "images" not in input_types["required"]
+    assert input_types["optional"]["images"] == ("IMAGE",)
+
+
+def test_audio_only_pass_through_returns_no_images_and_preserves_audio():
+    collector = _load_collector_module().DistributedCollectorNode()
+    audio = {"waveform": torch.ones(1, 2, 4), "sample_rate": 48000}
+
+    images, returned_audio = collector.run(images=None, audio=[audio])
+
+    assert images is None
+    assert returned_audio is audio
+
+
+def test_collector_rejects_missing_images_and_audio():
+    collector = _load_collector_module().DistributedCollectorNode()
+
+    try:
+        collector.run(images=None, audio=None)
+    except ValueError as exc:
+        assert "image or audio" in str(exc).lower()
+    else:
+        raise AssertionError("Expected collector to reject a run with no media input")
+
+
+def test_delegate_only_master_allows_no_local_media_input():
+    collector = _load_collector_module().DistributedCollectorNode()
+
+    images, audio = collector.run(
+        images=None,
+        audio=None,
+        multi_job_id=["delegate-audio-job"],
+        delegate_only=[True],
+        enabled_worker_ids=["[]"],
+    )
+
+    assert images is None
+    assert tuple(audio["waveform"].shape) == (1, 2, 1)
+
+
 def test_pass_through_collapses_comfyui_image_list_to_batch_and_unwraps_hidden_inputs():
     collector = _load_collector_module().DistributedCollectorNode()
     first = torch.zeros(1, 2, 2, 3)
@@ -203,3 +246,119 @@ def test_worker_list_input_sends_one_completion_sequence_with_last_only_on_final
     assert [payload["is_last"] for payload in posted_payloads] == [False, True]
     assert {payload["job_id"] for payload in posted_payloads} == {"job-list-1"}
     assert {payload["worker_id"] for payload in posted_payloads} == {"worker-a"}
+
+
+def test_audio_only_worker_sends_one_completion_without_image():
+    module = _load_collector_module()
+    collector = module.DistributedCollectorNode()
+    audio = {"waveform": torch.ones(1, 2, 4), "sample_rate": 48000}
+    posted = []
+
+    class _FakeResponse:
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, exc_type, exc, tb):
+            return False
+
+        def raise_for_status(self):
+            return None
+
+    class _FakeSession:
+        def post(self, url, json, timeout):
+            posted.append((url, json, timeout.total))
+            return _FakeResponse()
+
+    async def _fake_get_client_session():
+        return _FakeSession()
+
+    module.get_client_session = _fake_get_client_session
+    module.encode_audio_payload = lambda value: {"encoded": value is audio}
+
+    images, returned_audio = collector.run(
+        images=None,
+        audio=[audio],
+        multi_job_id=["audio-job"],
+        is_worker=[True],
+        master_url=["http://master"],
+        worker_id=["worker-a"],
+    )
+
+    assert images is None
+    assert returned_audio is audio
+    assert len(posted) == 1
+    assert posted[0][0] == "http://master/distributed/job_complete"
+    assert posted[0][2] == 600
+    assert posted[0][1] == {
+        "job_id": "audio-job",
+        "worker_id": "worker-a",
+        "batch_idx": 0,
+        "audio": {"encoded": True},
+        "is_last": True,
+    }
+
+
+def test_audio_only_master_combines_local_and_worker_audio():
+    module = _load_collector_module()
+    collector = module.DistributedCollectorNode()
+    master_audio = {"waveform": torch.ones(1, 2, 2), "sample_rate": 48000}
+    worker_audio = {"waveform": torch.full((1, 2, 3), 2.0), "sample_rate": 48000}
+    module.prompt_server.distributed_jobs_lock = asyncio.Lock()
+    queue = asyncio.Queue()
+    queue.put_nowait(
+        {
+            "worker_id": "worker-a",
+            "image_index": 0,
+            "tensor": None,
+            "audio": worker_audio,
+            "is_last": True,
+        }
+    )
+    module.prompt_server.distributed_pending_jobs = {"audio-job": queue}
+
+    images, combined_audio = asyncio.run(
+        collector.execute(
+            images=None,
+            audio=master_audio,
+            multi_job_id="audio-job",
+            enabled_worker_ids='["worker-a"]',
+        )
+    )
+
+    assert images is None
+    assert combined_audio["sample_rate"] == 48000
+    assert tuple(combined_audio["waveform"].shape) == (1, 2, 5)
+    assert torch.equal(combined_audio["waveform"][..., :2], master_audio["waveform"])
+    assert torch.equal(combined_audio["waveform"][..., 2:], worker_audio["waveform"])
+
+
+def test_delegate_only_audio_collects_worker_audio_without_placeholder_image():
+    module = _load_collector_module()
+    collector = module.DistributedCollectorNode()
+    worker_audio = {"waveform": torch.full((1, 2, 3), 2.0), "sample_rate": 48000}
+    module.prompt_server.distributed_jobs_lock = asyncio.Lock()
+    queue = asyncio.Queue()
+    queue.put_nowait(
+        {
+            "worker_id": "worker-a",
+            "image_index": 0,
+            "tensor": None,
+            "audio": worker_audio,
+            "is_last": True,
+        }
+    )
+    module.prompt_server.distributed_pending_jobs = {"delegate-audio-job": queue}
+
+    images, combined_audio = asyncio.run(
+        collector.execute(
+            images=None,
+            audio=None,
+            multi_job_id="delegate-audio-job",
+            enabled_worker_ids='["worker-a"]',
+            delegate_only=True,
+        )
+    )
+
+    assert images is None
+    assert combined_audio["sample_rate"] == 48000
+    assert torch.equal(combined_audio["waveform"], worker_audio["waveform"])

tests/test_payload_parsers.py

@@ -86,27 +86,25 @@ class ParseTilesFromFormTests(unittest.TestCase):
 
     # --- happy paths ---
 
-    def test_single_tile_returns_one_entry(self):
+    def test_single_tile_returns_image_and_metadata(self):
         tiles = pp._parse_tiles_from_form(_make_form(1))
         self.assertEqual(len(tiles), 1)
-
-    def test_multiple_tiles_all_returned(self):
-        tiles = pp._parse_tiles_from_form(_make_form(3))
-        self.assertEqual(len(tiles), 3)
-
-    def test_tile_image_is_pil_image(self):
-        tiles = pp._parse_tiles_from_form(_make_form(1))
-        self.assertIsInstance(tiles[0]["image"], PILImage.Image)
-
-    def test_tile_metadata_fields_are_parsed(self):
-        tiles = pp._parse_tiles_from_form(_make_form(1))
         tile = tiles[0]
+        self.assertIsInstance(tile["image"], PILImage.Image)
         self.assertEqual(tile["tile_idx"], 0)
         self.assertEqual(tile["x"], 0)
         self.assertEqual(tile["y"], 0)
         self.assertEqual(tile["extracted_width"], 64)
         self.assertEqual(tile["extracted_height"], 64)
 
+    def test_multiple_tiles_preserve_count_order_and_coordinates(self):
+        tiles = pp._parse_tiles_from_form(_make_form(3))
+        self.assertEqual(len(tiles), 3)
+        for i, tile in enumerate(tiles):
+            self.assertEqual(tile["tile_idx"], i)
+        self.assertEqual(tiles[1]["x"], 64)
+        self.assertEqual(tiles[2]["x"], 128)
+
     def test_padding_is_parsed_from_form(self):
         tiles = pp._parse_tiles_from_form(_make_form(1, padding=16))
         self.assertEqual(tiles[0]["padding"], 16)
@@ -138,16 +136,6 @@ class ParseTilesFromFormTests(unittest.TestCase):
         self.assertNotIn("batch_idx", tiles[0])
         self.assertNotIn("global_idx", tiles[0])
 
-    def test_tile_indices_match_metadata_order(self):
-        tiles = pp._parse_tiles_from_form(_make_form(3))
-        for i, tile in enumerate(tiles):
-            self.assertEqual(tile["tile_idx"], i)
-
-    def test_x_coordinates_reflect_metadata(self):
-        tiles = pp._parse_tiles_from_form(_make_form(3))
-        self.assertEqual(tiles[1]["x"], 64)
-        self.assertEqual(tiles[2]["x"], 128)
-
     # --- error cases ---
 
     def test_missing_tiles_metadata_raises_value_error(self):

tests/test_prompt_transform.py

@@ -71,6 +71,15 @@ def _collector_only_prompt():
     }
 
 
+def _audio_only_prompt():
+    """1(Audio source) → 2(DistributedCollector) → 3(Audio sink)."""
+    return {
+        "1": {"class_type": "LoadAudio", "inputs": {}},
+        "2": {"class_type": "DistributedCollector", "inputs": {"audio": ["1", 0]}},
+        "3": {"class_type": "SaveAudio", "inputs": {"audio": ["2", 1]}},
+    }
+
+
 def _delegate_prompt():
     """1 → 2 → 3(DistributedCollector) → 4(SaveImage)"""
     return {
@@ -217,6 +226,35 @@ class PrunePromptForWorkerTests(unittest.TestCase):
         self.assertEqual(len(preview_nodes), 1)
         self.assertEqual(preview_nodes[0]["inputs"]["images"], ["4", 0])
 
+    def test_injects_preview_audio_for_audio_only_collector(self):
+        result = pt.prune_prompt_for_worker(_audio_only_prompt())
+        preview_nodes = [n for n in result.values() if n.get("class_type") == "PreviewAudio"]
+        self.assertEqual(len(preview_nodes), 1)
+        self.assertEqual(preview_nodes[0]["inputs"]["audio"], ["2", 1])
+        self.assertFalse(any(n.get("class_type") == "PreviewImage" for n in result.values()))
+
+    def test_prefers_image_preview_when_collector_has_images_and_audio(self):
+        prompt = _linear_prompt()
+        prompt["6"] = {"class_type": "LoadAudio", "inputs": {}}
+        prompt["4"]["inputs"]["audio"] = ["6", 0]
+        result = pt.prune_prompt_for_worker(prompt)
+        self.assertEqual(
+            len([n for n in result.values() if n.get("class_type") == "PreviewImage"]),
+            1,
+        )
+        self.assertFalse(any(n.get("class_type") == "PreviewAudio" for n in result.values()))
+
+    def test_preserves_image_preview_for_distributed_upscale(self):
+        prompt = {
+            "1": {"class_type": "LoadImage", "inputs": {}},
+            "2": {"class_type": "UltimateSDUpscaleDistributed", "inputs": {"upscaled_image": ["1", 0]}},
+            "3": {"class_type": "SaveImage", "inputs": {"images": ["2", 0]}},
+        }
+        result = pt.prune_prompt_for_worker(prompt)
+        preview_nodes = [n for n in result.values() if n.get("class_type") == "PreviewImage"]
+        self.assertEqual(len(preview_nodes), 1)
+        self.assertEqual(preview_nodes[0]["inputs"]["images"], ["2", 0])
+
     def test_no_preview_image_when_no_downstream(self):
         result = pt.prune_prompt_for_worker(_collector_only_prompt())
         preview_nodes = [n for n in result.values() if n.get("class_type") == "PreviewImage"]
@@ -242,7 +280,7 @@ class PrunePromptForWorkerTests(unittest.TestCase):
     def test_upscale_node_is_treated_as_distributed(self):
         prompt = {
             "1": {"class_type": "KSampler", "inputs": {}},
-            "2": {"class_type": "UltimateSDUpscaleDistributed", "inputs": {"image": ["1", 0]}},
+            "2": {"class_type": "UltimateSDUpscaleDistributed", "inputs": {"upscaled_image": ["1", 0]}},
             "3": {"class_type": "SaveImage", "inputs": {"images": ["2", 0]}},
         }
         result = pt.prune_prompt_for_worker(prompt)
@@ -264,8 +302,8 @@ class PrepareDelegateMasterPromptTests(unittest.TestCase):
         self.assertNotIn("1", result)
         self.assertNotIn("2", result)
 
-    def test_removes_dangling_upstream_refs(self):
+    def test_replaces_dangling_upstream_ref_with_one_empty_image_placeholder(self):
-        """Collector must not retain dangling refs to pruned upstream nodes."""
+        """Collector must point to exactly one valid placeholder after pruning."""
         prompt = _delegate_prompt()
         result = pt.prepare_delegate_master_prompt(prompt, ["3"])
         collector_inputs = result["3"].get("inputs", {})
@@ -276,26 +314,520 @@ class PrepareDelegateMasterPromptTests(unittest.TestCase):
         self.assertNotEqual(source_id, "2")
         self.assertIn(source_id, result)
         self.assertEqual(result[source_id].get("class_type"), "DistributedEmptyImage")
-
-    def test_injects_empty_image_placeholder(self):
-        prompt = _delegate_prompt()
-        result = pt.prepare_delegate_master_prompt(prompt, ["3"])
         empty_nodes = [(nid, n) for nid, n in result.items() if n.get("class_type") == "DistributedEmptyImage"]
         self.assertEqual(len(empty_nodes), 1)
         placeholder_id = empty_nodes[0][0]
         self.assertEqual(result["3"]["inputs"]["images"], [placeholder_id, 0])
 
+    def test_audio_only_collector_does_not_get_image_placeholder(self):
+        prompt = _audio_only_prompt()
+        result = pt.prepare_delegate_master_prompt(prompt, ["2"])
+        empty_nodes = [n for n in result.values() if n.get("class_type") == "DistributedEmptyImage"]
+        self.assertEqual(empty_nodes, [])
+        self.assertNotIn("images", result["2"].get("inputs", {}))
+        self.assertNotIn("audio", result["2"].get("inputs", {}))
+
     def test_one_placeholder_per_collector(self):
         """Two collectors → two placeholders."""
         prompt = {
-            "1": {"class_type": "DistributedCollector", "inputs": {}},
+            "1": {"class_type": "DistributedCollector", "inputs": {"images": ["10", 0]}},
-            "2": {"class_type": "DistributedCollector", "inputs": {}},
+            "2": {"class_type": "DistributedCollector", "inputs": {"images": ["11", 0]}},
             "3": {"class_type": "SaveImage", "inputs": {"images": ["1", 0]}},
+            "10": {"class_type": "LoadImage", "inputs": {}},
+            "11": {"class_type": "LoadImage", "inputs": {}},
         }
         result = pt.prepare_delegate_master_prompt(prompt, ["1", "2"])
         empty_nodes = [n for n in result.values() if n.get("class_type") == "DistributedEmptyImage"]
         self.assertEqual(len(empty_nodes), 2)
 
+    def test_preserves_primitive_string_for_downstream_required_input(self):
+        """Delegate-only master keeps primitive inputs needed by SaveImage."""
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {"SaveImage": save_image}
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "test/input_bug"}},
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["15", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertIn("15", result)
+        self.assertEqual(result["15"], prompt["15"])
+        self.assertEqual(result["9"]["inputs"]["filename_prefix"], ["15", 0])
+
+    def test_preserves_load_image_for_switch_alternate_required_input(self):
+        """Delegate-only master keeps LoadImage inputs needed by switches."""
+        prompt = {
+            "848": {"class_type": "LoadImage", "inputs": {"image": "input_bug2_00003_.png"}},
+            "862": {"class_type": "VAEDecode", "inputs": {}},
+            "854": {"class_type": "DistributedCollector", "inputs": {"images": ["862", 0]}},
+            "850": {
+                "class_type": "ComfySwitchNode",
+                "inputs": {
+                    "on_false": ["848", 0],
+                    "on_true": ["854", 0],
+                },
+            },
+            "851": {"class_type": "PreviewImage", "inputs": {"images": ["850", 0]}},
+        }
+
+        result = pt.prepare_delegate_master_prompt(prompt, ["854"])
+
+        self.assertIn("848", result)
+        self.assertEqual(result["850"]["inputs"]["on_false"], ["848", 0])
+        self.assertEqual(result["850"]["inputs"]["on_true"], ["854", 0])
+        self.assertNotIn("862", result)
+
+    def test_preserves_registered_string_utility_subgraph_for_downstream_required_input(self):
+        """Delegate-only master keeps scalar utility chains used by SaveImage."""
+        string_concat = type(
+            "StringConcatenate",
+            (),
+            {
+                "RETURN_TYPES": ("STRING",),
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "string_a": ("STRING",),
+                            "string_b": ("STRING",),
+                        }
+                    }
+                ),
+            },
+        )
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "SaveImage": save_image,
+            "StringConcatenate": string_concat,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "test"}},
+                "16": {"class_type": "PrimitiveString", "inputs": {"value": "input_bug3"}},
+                "17": {
+                    "class_type": "StringConcatenate",
+                    "inputs": {
+                        "string_a": ["15", 0],
+                        "string_b": ["16", 0],
+                    },
+                },
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["17", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertIn("15", result)
+        self.assertIn("16", result)
+        self.assertIn("17", result)
+        self.assertEqual(result["9"]["inputs"]["filename_prefix"], ["17", 0])
+        self.assertEqual(result["17"]["inputs"]["string_a"], ["15", 0])
+        self.assertEqual(result["17"]["inputs"]["string_b"], ["16", 0])
+
+    def test_preserves_registered_multi_string_join_subgraph_for_downstream_required_input(self):
+        """Delegate-only master keeps multi-input scalar utility chains."""
+        join_string_multi = type(
+            "JoinStringMulti",
+            (),
+            {
+                "RETURN_TYPES": ("STRING",),
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {"string_1": ("STRING",)},
+                        "optional": {
+                            "string_2": ("STRING",),
+                            "string_3": ("STRING",),
+                        },
+                    }
+                ),
+            },
+        )
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "JoinStringMulti": join_string_multi,
+            "SaveImage": save_image,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "test"}},
+                "16": {"class_type": "PrimitiveString", "inputs": {"value": "input"}},
+                "17": {"class_type": "PrimitiveString", "inputs": {"value": "bug4"}},
+                "18": {
+                    "class_type": "JoinStringMulti",
+                    "inputs": {
+                        "string_1": ["15", 0],
+                        "string_2": ["16", 0],
+                        "string_3": ["17", 0],
+                    },
+                },
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["18", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertIn("15", result)
+        self.assertIn("16", result)
+        self.assertIn("17", result)
+        self.assertIn("18", result)
+        self.assertEqual(result["9"]["inputs"]["filename_prefix"], ["18", 0])
+
+    def test_does_not_preserve_scalar_utility_with_heavy_upstream_dependency(self):
+        """Scalar utility nodes are retained only when their full input branch is safe."""
+        string_concat = type(
+            "StringConcatenate",
+            (),
+            {
+                "RETURN_TYPES": ("STRING",),
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "string_a": ("STRING",),
+                            "string_b": ("STRING",),
+                        }
+                    }
+                ),
+            },
+        )
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "SaveImage": save_image,
+            "StringConcatenate": string_concat,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "test"}},
+                "17": {
+                    "class_type": "StringConcatenate",
+                    "inputs": {
+                        "string_a": ["15", 0],
+                        "string_b": ["8", 0],
+                    },
+                },
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["17", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertNotIn("8", result)
+        self.assertNotIn("17", result)
+        self.assertNotIn("filename_prefix", result["9"]["inputs"])
+
+    def test_does_not_preserve_scalar_output_for_non_scalar_downstream_input(self):
+        """Scalar outputs are retained only for scalar/config downstream inputs."""
+        string_provider = type("StringProvider", (), {"RETURN_TYPES": ("STRING",)})
+        image_consumer = type(
+            "ImageConsumer",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "mask": ("IMAGE",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "ImageConsumer": image_consumer,
+            "StringProvider": string_provider,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "17": {"class_type": "StringProvider", "inputs": {}},
+                "9": {
+                    "class_type": "ImageConsumer",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "mask": ["17", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertNotIn("17", result)
+        self.assertNotIn("mask", result["9"]["inputs"])
+
+    def test_preserves_scalar_list_join_subgraph_for_downstream_required_input(self):
+        """Delegate-only master keeps list-shaped scalar config chains."""
+        create_list = type(
+            "CreateList",
+            (),
+            {
+                "RETURN_TYPES": ("LIST",),
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {"inputs.input0": ("STRING",)},
+                        "optional": {
+                            "inputs.input1": ("STRING",),
+                            "inputs.input2": ("STRING",),
+                        },
+                    }
+                ),
+            },
+        )
+        string_data_list_join = type(
+            "StringDataListJoin",
+            (),
+            {
+                "RETURN_TYPES": ("STRING",),
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "strings": ("LIST",),
+                            "delimiter": ("STRING",),
+                        }
+                    }
+                ),
+            },
+        )
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "CreateList": create_list,
+            "SaveImage": save_image,
+            "StringDataListJoin": string_data_list_join,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "test"}},
+                "17": {"class_type": "PrimitiveString", "inputs": {"value": "input_bug"}},
+                "29": {"class_type": "PrimitiveString", "inputs": {"value": "new"}},
+                "28": {
+                    "class_type": "CreateList",
+                    "inputs": {
+                        "inputs.input0": ["15", 0],
+                        "inputs.input1": ["17", 0],
+                        "inputs.input2": ["29", 0],
+                    },
+                },
+                "32": {
+                    "class_type": "StringDataListJoin",
+                    "inputs": {
+                        "strings": ["28", 0],
+                        "delimiter": "/",
+                    },
+                },
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["32", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        self.assertIn("15", result)
+        self.assertIn("17", result)
+        self.assertIn("28", result)
+        self.assertIn("29", result)
+        self.assertIn("32", result)
+        self.assertEqual(result["9"]["inputs"]["filename_prefix"], ["32", 0])
+        self.assertEqual(result["32"]["inputs"]["strings"], ["28", 0])
+        self.assertEqual(result["28"]["inputs"]["inputs.input0"], ["15", 0])
+        self.assertNotIn("8", result)
+
+    def test_preserves_builtin_create_list_string_data_list_join_subgraph(self):
+        """Delegate-only master handles ComfyUI 0.23 CreateList data-list output."""
+        string_data_list_join = type(
+            "StringDataListJoin",
+            (),
+            {
+                "RETURN_TYPES": ("STRING",),
+                "INPUT_IS_LIST": True,
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "strings": ("STRING", {"forceInput": True}),
+                            "sep": ("STRING", {"default": " "}),
+                        }
+                    }
+                ),
+            },
+        )
+        save_image = type(
+            "SaveImage",
+            (),
+            {
+                "INPUT_TYPES": classmethod(
+                    lambda cls: {
+                        "required": {
+                            "images": ("IMAGE",),
+                            "filename_prefix": ("STRING",),
+                        }
+                    }
+                )
+            },
+        )
+        previous_mappings = getattr(pt, "_DELEGATE_MASTER_NODE_CLASS_MAPPINGS", None)
+        pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = {
+            "Basic data handling: StringDataListJoin": string_data_list_join,
+            "SaveImage": save_image,
+        }
+        try:
+            prompt = {
+                "8": {"class_type": "KSampler", "inputs": {}},
+                "11": {"class_type": "DistributedCollector", "inputs": {"images": ["8", 0]}},
+                "15": {"class_type": "PrimitiveString", "inputs": {"value": "input_bug"}},
+                "17": {"class_type": "PrimitiveString", "inputs": {"value": "test"}},
+                "29": {"class_type": "PrimitiveString", "inputs": {"value": "new"}},
+                "28": {
+                    "class_type": "CreateList",
+                    "inputs": {
+                        "inputs.input0": ["17", 0],
+                        "inputs.input1": ["15", 0],
+                        "inputs.input2": ["29", 0],
+                    },
+                },
+                "32": {
+                    "class_type": "Basic data handling: StringDataListJoin",
+                    "inputs": {
+                        "strings": ["28", 0],
+                        "sep": "/",
+                    },
+                },
+                "9": {
+                    "class_type": "SaveImage",
+                    "inputs": {
+                        "images": ["11", 0],
+                        "filename_prefix": ["32", 0],
+                    },
+                },
+            }
+
+            result = pt.prepare_delegate_master_prompt(prompt, ["11"])
+        finally:
+            pt._DELEGATE_MASTER_NODE_CLASS_MAPPINGS = previous_mappings
+
+        for node_id in ("15", "17", "28", "29", "32"):
+            self.assertIn(node_id, result)
+        self.assertEqual(result["9"]["inputs"]["filename_prefix"], ["32", 0])
+        self.assertEqual(result["32"]["inputs"]["strings"], ["28", 0])
+        self.assertEqual(result["28"]["inputs"]["inputs.input0"], ["17", 0])
+        self.assertNotIn("8", result)
+
     def test_result_is_independent_copy(self):
         prompt = _delegate_prompt()
         result = pt.prepare_delegate_master_prompt(prompt, ["3"])

web/sidebar/settingsSection.js

@@ -72,7 +72,7 @@ export function renderSettingsSection(extension) {
         createCheckboxSetting(
             "setting-debug",
             "Debug Mode",
-            "Enable verbose logging in the browser console.",
+            "Enable verbose logging in the browser console and ComfyUI server output.",
             extension.config?.settings?.debug || false,
             (event) => extension._updateSetting("debug", event.target.checked)
         )
@@ -100,7 +100,7 @@ export function renderSettingsSection(extension) {
         createNumberSetting(
             "setting-worker-timeout",
             "Worker Timeout",
-            "Seconds without a heartbeat before a worker is considered timed out. Default 60.",
+            "Maximum result-wait and heartbeat inactivity period before recovery begins. Busy workers may receive additional grace. Default: 60 seconds.",
             extension.config?.settings?.worker_timeout_seconds ?? 60,
             10,
             1,

web/tests/executionUtils.test.js

@@ -1,15 +0,0 @@
-import { describe, expect, it } from "vitest";
-
-import { buildWorkerWebSocketUrl } from "../urlUtils.js";
-
-
-describe("execution decision helpers", () => {
-    it("buildWorkerWebSocketUrl converts http/https to ws/wss", () => {
-        expect(buildWorkerWebSocketUrl("http://worker.local:8188")).toBe(
-            "ws://worker.local:8188/distributed/worker_ws"
-        );
-        expect(buildWorkerWebSocketUrl("https://worker.example.com")).toBe(
-            "wss://worker.example.com/distributed/worker_ws"
-        );
-    });
-});

web/tests/urlUtils.test.js

@@ -106,11 +106,6 @@ describe("buildWorkerWebSocketUrl", () => {
             "wss://worker.example.com/distributed/worker_ws"
         );
     });
-
-    it("always appends /distributed/worker_ws", () => {
-        const url = buildWorkerWebSocketUrl("http://worker.local:8188");
-        expect(url.endsWith("/distributed/worker_ws")).toBe(true);
-    });
 });
 
 

web/tests/workerLifecycle.test.js

@@ -3,7 +3,7 @@ import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { getWorkerUrl } from "../workerLifecycle.js";
 
 
-describe("workerLifecycle URL construction", () => {
+describe("workerLifecycle URL wiring", () => {
     let originalWindow;
 
     beforeEach(() => {
@@ -22,31 +22,9 @@ describe("workerLifecycle URL construction", () => {
         globalThis.window = originalWindow;
     });
 
-    it("builds local worker URL with explicit local port", () => {
+    // URL variants are covered in urlUtils.test.js; keep the wrapper wiring here.
+    it("forwards the worker and endpoint using window.location", () => {
         const worker = { id: "w1", port: 8189, type: "local" };
         expect(getWorkerUrl({}, worker, "/prompt")).toBe("http://127.0.0.1:8189/prompt");
     });
-
-    it("builds remote worker URL with host:port", () => {
-        const worker = { id: "w2", host: "worker.example.com", port: 9000, type: "remote" };
-        expect(getWorkerUrl({}, worker, "/prompt")).toBe("http://worker.example.com:9000/prompt");
-    });
-
-    it("builds cloud worker URL as https", () => {
-        const worker = { id: "w3", host: "cloud.example.com", port: 443, type: "cloud" };
-        expect(getWorkerUrl({}, worker, "/prompt")).toBe("https://cloud.example.com/prompt");
-    });
-
-    it("rewrites runpod proxy hostname for local worker ports", () => {
-        globalThis.window = {
-            location: {
-                hostname: "podabc.proxy.runpod.net",
-                protocol: "https:",
-                port: "",
-                origin: "https://podabc.proxy.runpod.net",
-            },
-        };
-        const worker = { id: "w4", port: 8189, type: "local" };
-        expect(getWorkerUrl({}, worker, "/prompt")).toBe("https://podabc-8189.proxy.runpod.net/prompt");
-    });
 });

workflows/distributed-upscale.json

@@ -814,7 +814,7 @@
       "outputs": [],
       "properties": {},
       "widgets_values": [
-        "If all your GPUs are the same/similar, set static_distribution to true\n"
+        "Workers pull tiles from a shared queue, so faster workers can process more tiles automatically.\n"
       ],
       "color": "#432",
       "bgcolor": "#653"