Concatenate Text (Autogrow)

String concatenation is ComfyUI's most boring recurring task and this node makes it marginally less tedious. UC_TextConcatenateAutogrow takes any number of text inputs and joins them in order with a delimiter you choose. The "autogrow" in the name is the whole trick: instead of a fixed set of inputs, the node grows new sockets as you connect more wires, up to a hundred of them.

Why you'd reach for it

Modular prompts. You keep a subject box, a style box, a quality box, and a lighting box as separate text nodes, then join them here with , between them. Change one component and the assembled prompt updates without you retyping the whole thing. It's also the natural endpoint for wildcard-style systems: each text_N input can be a dropdown or a wildcard that resolves to a fragment, and this node stitches the fragments together with your delimiter before the text hits an encoder.

The autogrow inputs accept any type and stringify them - the tooltip says it plainly: "Values joined in their input order." So you can even join non-string values if that's somehow what your graph wants.

How it works

Inputs are ordered by their index - text_1, text_2, text_3 - not by where you happen to drag a wire, so the join order is stable and predictable. The optional delimiter input sits between every joined value; leave it empty and the parts are joined with nothing between them. The output is a single concatenated_text STRING. Simple, but that's the appeal - it does the one thing with no surprises.

One small gotcha hiding in the name: this is the scalar joiner. If you feed it lists of strings expecting element-wise joining, you want the sibling node UC_TextConcatenateListsAutogrow, which is built for index-aligned list merging with broadcasting.

Installing it

It's part of ComfyUI-UtilsCollection (author: silveroxides):

cd ComfyUI/custom_nodes
git clone https://github.com/silveroxides/ComfyUI-UtilsCollection

Restart ComfyUI, or install "ComfyUI-UtilsCollection" via Manager. Dependencies are the pack's minimal pair, opencv-python and typing-extensions - this node uses neither.

Where people get burned

Two things. First, empty inputs are joined too - if one fragment is blank you can get double delimiters ("subject,, style") unless your source nodes output empty strings cleanly. Second, if you're on the older pre-autogrow frontend, the "add socket" behavior may not be as smooth; the autogrow mechanism is a Nodes 2.0-era feature, so a recent ComfyUI matters. Neither is a dealbreaker, but both are the classic friction points when people say "my prompt has stray commas."