ComfyUI template preflight: trace which branches and settings reach the sampler (bypass, switches, subgraph values, linked widgets)

ComfyUI template preflight: trace what actually reaches the sampler Why this matters. In official ComfyUI templates, the values shown on a sampler node are often not the values that run. Links from switches, primitives, math nodes or a subgraph wrapper can override them. Whole stages can be bypassed. A template's own notes can disagree with its loader nodes. This method reads a workflow JSON statically, without running it. Two official templates in Comfy-Org/workflow_templates at commit 0cc0fba562efe9f68e48050c2b82ed6495050bc2 serve as worked examples: HunyuanVideo 1.5 720p I2V (a flat graph whose optional stages are bypassed nodes) and Qwen-Image-Edit-2511 (a subgraph wrapper driven by switches). Model-specific setup lives in the two per-template guides; this record is the method. Step 1. Map the scopes. The root has "nodes" and "links". Embedded subgraphs sit under definitions.subgraphs, each with its own nodes, links, inputs and outputs. A root node whose type is a subgraph id (a UUID) is a wrapper instance of that subgraph. In the Qwen template, node 170's type is cdb2cf24-c432-439b-b5c8-5f69838580c9, the "Image Edit (Qwen-Image 2511)" subgraph with 23 nodes. The HunyuanVideo template has no subgraph: all 45 nodes are at the root. Step 2. Read node modes. Mode 0 runs. Mode 2 (muted) never runs. Mode 4 (bypassed) is skipped and normally passes its inputs through to matching outputs. Group titles often tell you how to switch a stage on. In the HunyuanVideo template, every node in the "Video Upscale 1080P (Ctrl-B to enable)" group is saved as mode 4, including UNETLoader 111 and LatentUpscaleModelLoader 108. EasyCache 105 is also mode 4, so the base model reaches the scheduler and the shift node unchanged. Step 3. Resolve every sampler setting. For each widget the sampler, guider or scheduler uses, check whether that input slot has a link. If it does, the saved widget value is not used; follow the link to its origin: - A primitive (PrimitiveInt, PrimitiveFloat, PrimitiveBoolean) supplies its value, unless its own value input is itself linked, for example from a subgraph input. - A ComfySwitchNode supplies on_true or on_false according to the boolean on its switch input. Evaluate it for each state you plan to use. - A math expression supplies arithmetic on its resolved inputs. That is a requested value, not an observed output. - A subgraph input leads back to the wrapper. Values stored in the wrapper's widgets_values line up, in order, with the definition's widget-typed inputs. If the wrapper stores none, its promoted proxyWidgets point back to the inner node's own widget value. Qwen example: KSampler 169 stores 40 steps and CFG 3, but both inputs are linked, to Switch (Steps) 167 and Switch (CFG) 164. Both switches read "Enable 4steps LoRA?" (168), whose value comes from the wrapper and is saved off. The settings that run are 40 steps at CFG 4, or 4 steps at CFG 1 with the switch on. The stored CFG 3 never runs. Step 4. Trace each model input separately. A sampler, a guider and a scheduler can each receive the model from a different point in the graph. In the HunyuanVideo template, CFGGuider 129 gets the model through ModelSamplingSD3 130 (shift 7), while BasicScheduler 126 takes its model from EasyCache 105, before the shift node. Record such differences. The file does not say whether they are intended, and their runtime effect needs a test. Step 5. Walk back from every save node. A node whose output connects to nothing does nothing even when enabled. In the HunyuanVideo template, VAEDecodeTiled 120 is bypassed and its IMAGE output has no link, so enabling it alone does not change decoding. To use it, connect it to CreateVideo 101 in place of VAEDecode 8. Step 6. Separate required files from optional ones, then check the notes. Files named on loaders in the active path are required for that configuration. Files on bypassed loaders, or on a switch branch you are not using, are optional for it. Do not delete those loaders or files, though: the graph does not show whether a runtime evaluates an unselected branch. Then compare each loader's properties.models declaration with the template's download note. The HunyuanVideo note lists five files but omits the two that the bypassed 1080p loaders declare. The Qwen note lists qwen_image_edit_2511_bf16, while UNETLoader 161 selects, and declares a download for, qwen_image_edit_2511_fp8mixed. Step 7. Find where the output size comes from: an empty-latent widget, a linked math expression or an input image. The Qwen template has no empty latent. VAEEncode 156 encodes image 1 after FluxKontextImageScale 160, so the output size follows image 1. The HunyuanVideo template stores 1280, 720 and 121 unlinked on HunyuanVideo15ImageToVideo 78. Step 8. Record seeds and their control mode. A seed set to randomize changes on every run, like the Qwen seed promoted on the wrapper. A fixed seed stays, like HunyuanVideo's RandomNoise 127. Step 9. Treat metadata and notes as statements. Saved node and frontend versions are not a tested minimum. Template notes are author statements and can contain errors: the HunyuanVideo OOM note spells the weight_dtype option fp8_e4n3fn, but the FP8 format is e4m3fn. Preflight checklist 1. List the scopes, wrappers and subgraph definitions. 2. List bypassed and muted nodes, and the groups they belong to. 3. For every sampler, guider and scheduler widget: is it linked? Resolve its source and value for each switch state. 4. Trace the MODEL input of the sampler, guider and scheduler separately. 5. Walk back from each save node and flag enabled nodes whose outputs go nowhere. 6. Split required files (active loaders) from optional ones (bypassed or unselected branches), and compare them with the template note. 7. Identify the source of the output size. 8. Note each seed and its control mode. 9. Record the graph revision or hash and the resolved settings before you run anything. Limits. Everything here is static reading. Node implementations were not read, so bypass and lazy-evaluation behaviour follow ComfyUI's general rules rather than a test. Arithmetic results are requested values, not observed outputs. Nothing was executed. Related records. "HunyuanVideo 1.5 720p I2V ComfyUI template (video_hunyuan_video_1.5_720p_i2v)" and "Qwen-Image-Edit-2511 ComfyUI template (image_qwen_image_edit_2511)" give the model-specific setup. "Wan 2.2 14B T2V ComfyUI template (video_wan2_2_14B_t2v)" applies the same method to a switch-driven subgraph. Evidence and rights. Evidence status: source_inspected, not_run, unreviewed. This is shared-founder desk curation by the tutorial lane. The workflow repository declares the MIT licence at this commit; that covers this method and its analysis of the templates, not the models, encoders, VAEs, LoRAs, inputs or outputs they reference.

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