Fill Example: Hello World

Let's be honest about what this is: Fill Example: Hello World does almost nothing. You type some text, it hands you back the same text with "You said:" glued onto the front. It's not a node you'll find missing in someone's workflow, it won't unblock a generation, and nobody in the community is swapping tips about it. If you came here from a Google search, the real answer to "what does this node do" is: it's a teaching prop.

And that's fine, because the whole pack it lives in is a tutorial wearing a custom-node pack's clothes. The author - a ComfyUI dev who publishes as MachineDelusions and knows his way around this ecosystem - shipped these example nodes explicitly so people can read the source and learn how to build their own. Hello World is the on-ramp: the smallest possible custom node that still does something.

How it works

Under the hood it's about twenty lines of Python and it's the skeleton every classic custom node shares. The class defines an INPUT_TYPES method (this one has a single required text string), a RETURN_TYPES tuple (one STRING), a FUNCTION name pointing at run, and a CATEGORY for the menu. The __init__.py in the pack registers it in NODE_CLASS_MAPPINGS and NODE_DISPLAY_NAME_MAPPINGS, which is what makes it show up under "Fill-Example-Nodes" in the node menu at all.

The one interesting detail: the node doesn't display anything itself. It returns "You said: {text}" as a STRING output - that's just data on a wire. ComfyUI nodes that output strings are passive; you have to feed the wire into a display node like core's Show Text to actually see it. That's a genuine "oh, that's how this ecosystem works" moment for a beginner, and honestly it's the most useful thing the node teaches you.

Inputs and outputs that matter

There's exactly one input and one output, so this is a short list:

• text (STRING) - what you type. Default "Hello, World!", single-line (multiline is off). This is the one you'll actually touch.
• STRING output - the text echoed back with the You said: prefix. Wire it into a Show Text node to see the result, or into anything else that consumes a string.

Install

This pack has no Python dependencies (its requirements.txt is literally a comment) and downloads no models, so installation is the easy kind:

• ComfyUI Manager → Install Custom Nodes → search "ComfyUI_Fill-Example-Nodes" (or "Fill Example") → install → restart ComfyUI.
• Or the manual way:

cd ComfyUI/custom_nodes
git clone https://github.com/filliptm/ComfyUI_Fill-Example-Nodes

Then restart ComfyUI. No pip install, no model files, nothing to babysit.

Common issues

Honestly, there's almost nothing to go wrong - the node can't fail in an interesting way. Two things worth knowing:

• The output is invisible until you wire it somewhere, so if "nothing happened" it's because STRING outputs don't render on their own. That's not a bug.
• If you load the pack's bundled Example-Nodes.json workflow and ComfyUI complains about a missing FLExampleJsNode, that's expected - the example workflow references a node the current code doesn't register. Ignore the warning, the other four example nodes load fine.

The real takeaway: don't use this node to make images. Use it to learn how a node is put together. Read the source, copy the skeleton, and build the node you actually wanted.