# UTFCN — Use The F***ing Core Nodes A ComfyUI companion that nudges your workflows back toward **core nodes**. Over time a graph accumulates custom nodes that just re-implement things ComfyUI now ships itself. UTFCN spots those and helps you swap them out — fewer dependencies, more portable workflows. It does three things: 1. **On add** — drop a custom node that has a core (or otherwise installed) equivalent and, depending on the mode, UTFCN either shows a quiet tip or (in **Force mode**) auto-replaces it with the equivalent on the spot. 2. **Replace across a workflow** — `Extensions ▸ UTFCN ▸ Replace custom nodes with core / available…` (also in the command palette). It scans the open graph and shows a **preview** of every swap before anything changes. 3. **Replace one node** — right-click any custom node ▸ **Replace with core / available**. Nothing is ever swapped without your say-so, and the engine only rewires slots it can move *losslessly* — anything it can't map is reported, not guessed. ### Works on uninstalled ("missing") nodes The headline case: open a downloaded workflow full of red **missing** nodes and replace them with core equivalents **without installing the packs at all**. ComfyUI keeps each missing node as a placeholder that remembers its original type and wiring, so UTFCN can still match and swap it — via a curated rule (by name) or by matching the node's *serialized* signature against your core nodes. Both "Replace…" and the right-click item work on them; the bulk dialog labels them `⚠ not installed`. (Widget values aren't carried for a node whose definition you don't have — links are.) ## How it decides what's equivalent The backend reads the live node registry (real `INPUT_TYPES` / `RETURN_TYPES` and each node's source module) and ranks candidates in three tiers: | Tier | Meaning | Auto-applied? | |------|---------|---------------| | **curated** | a hand-written rule in `mappings.json` / `user_mappings.json` | yes (verified) | | **exact** | identical input names+types and output types to a core/other-pack node | yes (verified) | | **partial** | can structurally stand in (accepts all inputs, provides all outputs) but names/slots differ | suggestion only | "Available" means core is preferred, and if there's no core match it will offer an equivalent from a **different installed pack** as a fallback. For an **uninstalled** node only *curated* (by name) and *partial* (by its serialized link signature) can apply — the exact tier needs the widget-level signature, which a node you haven't installed can't provide. ## Shipped equivalences `mappings.json` ships a small, hand-verified set (each checked lossless against the real core signatures): - `GetImageSize+` (essentials) → core `GetImageSize` - `MaskPreview+` (essentials) → core `MaskPreview` - `BOOLConstant` / `INTConstant` / `FloatConstant` (KJNodes) → core `PrimitiveBoolean` / `PrimitiveInt` / `PrimitiveFloat` - `Convert Masks to Images` / `Mask Invert` (WAS) → core `MaskToImage` / `InvertMask` Rules for nodes you don't have installed are simply ignored. Everything else is found live: exact-signature matches auto-apply, looser ones are suggested. ## Adding your own equivalences To bless a partial match as safe, or to fix up slots whose names differ, add a rule to **`user_mappings.json`** (merged over the shipped `mappings.json`, survives updates): ```json { "rules": { "SomeCustomNode": [ { "to": "CoreNode", "note": "why they're equivalent (shown in the preview)", "inputs": { "old_input": "new_input" }, "widgets": { "old_widget": "new_widget" }, "outputs": { "old_output": "new_output" } } ] } } ``` List targets in preference order (put the core node first). Any slot you don't list is matched by identical name, then by type + order. After editing, run `Extensions ▸ UTFCN ▸ Refresh equivalence index` (no restart needed). ## Settings **UTFCN ▸ On add ▸ When adding a custom node that has a core / available equivalent:** - **Off** — do nothing. - **Suggest** (default) — show a tip pointing at the equivalent. - **Force (auto-replace with core)** — immediately swap it for the equivalent. Force only ever applies **verified** matches (curated or exact-signature); it never auto-applies a heuristic guess, and it never fires while you're opening or importing a workflow — only on nodes *you* add. Undo with Ctrl+Z. ## Install Clone into `ComfyUI/custom_nodes/` and restart ComfyUI: ``` git clone https://github.com/ethanfel/ComfyUI-UTFCN ``` No Python dependencies. The node adds a single read-only server route (`/utfcn/scan`) and a frontend extension. ## License GPL-3.0-or-later. See [LICENSE](LICENSE).