Concat Strings

Every prompt-building workflow eventually asks the same dumb question: how do I stick "cinematic, " in front of my base prompt? There are a hundred string-join nodes across a hundred packs, and they're all basically the same node - this is this pack's version. UtilConcatStrings takes two strings and joins them with a configurable separator. That's it. It's not the node you brag about; it's the node you actually reach for a dozen times while wiring up a real workflow.

How it works

string_a, then separator, then string_b, concatenated in that order. If the separator defaults to a single space and you want ", " instead, you just type it in - there's no hidden trimming or smart-comma logic. Both strings are marked forceInput, which means the fields are always connectable from upstream nodes rather than being plain widget text. That's the detail that makes it genuinely useful: you can pipe a generated description or a wildcard expansion straight in and have it slot into the middle of a sentence structure.

The inputs and output

• string_a (STRING) - first fragment.
• string_b (STRING) - second fragment.
• separator (STRING, optional, default " ") - what goes between them. Set to ", " for a comma-space, "\n" for a line break.
• joined_string (STRING) - a + sep + b, ready for a text encoder or another concat.

Where it fits

Use it to assemble prompt parts - style + subject, positive + dynamic-prompt expansion, a LoRA trigger bolted onto a base. Chain two of them together and you get three-way joins; it composes fine. The one thing it deliberately does not do is batch: it's strictly two strings in, one string out.

That's where it differs from its sibling in this pack. SBConcatStrings is the list-aware version - up to twenty string lists merged element-by-element, built for storyboard batch pipelines. UtilConcatStrings is the simple two-value join. If you're working on a single prompt, this is the one; if you're processing a batch of per-scene fragments, you want the SB version. Both sit in the same pack, so you don't have to install anything extra to move between them.

Install

Ships in the IXIWORKS pack - ComfyUI Manager → search ComfyUI-VideoDescription → Install, restart, or clone the repo into custom_nodes/. Zero extra dependencies; it's pure string handling. There's nothing clever to break or troubleshoot - if the output looks wrong, check your separator, because that's the entire surface area of this node.