FL Prompt Basic

Fill-Nodes has a small prompting section tucked inside its much larger pile of image, PDF, and AI-API nodes, and FL_PromptBasic is the plainest tool in it: three text boxes concatenated into one string, no formatting decisions made on your behalf. If you've ever fought a prompt-builder node that insists on inserting its own commas or spaces where you didn't want them, this is the antidote - it does exactly nothing extra.

How it works

It takes three multiline strings - prepend, prompt, append - and joins them in that order with zero characters added between them. Not a space, not a comma, nothing. Whatever separator you want has to already be sitting at the end of prepend or the start of append.

That sounds almost too simple to write up, but it's the right tool for a common situation: you've got a base prompt coming out of a caption node or a FL_PromptSelector, and you want to consistently wrap it with a trigger word or a style suffix without a builder node quietly reformatting your text.

The inputs and outputs that matter

• prepend - text placed before the prompt. Useful for LoRA trigger words, quality tags, or a consistent subject phrase you always want up front.
• prompt - the variable middle, typically wired from an upstream generator/selector rather than typed by hand.
• append - text placed after. A style suffix, negative-space reminder, or anything you want anchored at the end.

All three default to empty strings, so you can use this with just one or two of them filled in - it degrades gracefully to a pass-through if you leave prepend and append blank.

The output is a single STRING - wire it wherever a text prompt goes: a CLIP text encode, another Fill-Nodes prompting node, or FL_ShowText if you want to sanity-check the exact concatenated result before it hits your sampler.

How to install it

ComfyUI Manager: search "Fill-Nodes", install, restart. Manual:

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

No extra dependencies for this one specifically - it's pure string concatenation - though installing the pack pulls in everything else Fill-Nodes needs for its heavier nodes too. Restart ComfyUI once it's cloned.

Common issues & troubleshooting

Words running together with no space. This is the single most common surprise, and it's not a bug - it's the entire point of the node. If your output reads like masterpiecea photo of a cat, that's because prepend ended in "masterpiece" with no trailing space. Add the space (or comma) yourself at the end of prepend and the start of append.

Expecting it to dedupe or clean tags. It won't - there's no tag parsing, no comma normalization, nothing smart. If you need that, look elsewhere in the pack's prompting or utility nodes; this one is deliberately dumb, which is exactly why it's predictable.

Multiline fields collapsing oddly. Since all three inputs are multiline, a trailing newline in prepend becomes a literal newline in the middle of your final prompt. Most CLIP encoders tolerate that fine, but if you're feeding the result somewhere newline-sensitive, trim your inputs first.