CSV List Appender

Building up a comma-separated list one value at a time is a recurring need in ComfyUI - a growing tag list, a set of filenames you're collecting, a queue of things to iterate over. Do it by hand and you get duplicates, stray commas, and mismatches. CSV List Appender is the small node that does it for you, with a dedupe guard you'll appreciate the first time you accidentally feed it the same value twice.

How it works

The logic is refreshingly honest. The node takes your existing CSV string, splits it on commas into a set, and checks whether the value you're appending is already in there:

• If it's not present, it adds a comma (unless the string is empty or already ends in one) and appends the value.
• If it is present, it does nothing.

That's the whole mechanism. The set-based dedupe means you can chain it repeatedly with values drawn from other nodes and never worry about polluting your list with repeats. It's the "grow a list safely" node of this pack.

Inputs and outputs

• input_csv_string - the list so far, multiline.
• append_value - the value to add, multiline.

The output is Output CSV String - your list with the new value tacked on (or unchanged if it was a duplicate).

Two things worth knowing

First, the dedupe compares values exactly as they appear after the comma split - there's no whitespace stripping, so "dog" and "dog " count as different entries. If you're feeding in values with trailing spaces, trim them upstream or you'll quietly defeat the whole point of the node.

Second, this is a pure pass-through tool: it returns the modified string but doesn't write anywhere. Wire its output into a text-save node, a display node, or another appender in a chain to keep building the list, and eventually into whatever consumes the CSV - including the pack's own ConvertCsvToJson, if you want the accumulated list turned into a JSON array.

Install

ComfyUI Manager → search "comfy-nekonote-extensions", or:

cd ComfyUI/custom_nodes
git clone https://github.com/0nyx-networks/comfy-nekonote-extensions

Restart ComfyUI and it's under NEKONOTE → Text. It's one of the small MIT-licensed utilities in comfy-nekonote-extensions (MINETA "m10i" Hiroki, v0.4.7) - no models, no GPU, no real dependencies beyond what ComfyUI ships. Keep ComfyUI current: the pack is built against the newer comfy_api.latest backend API, and an old core won't register its nodes.