MD: Smart Filename Builder

Two weeks after a big batch, every file in your output folder is a mystery: which seed was that, what steps, what genre? SmartFilenameBuilder exists so your filenames answer those questions before you open anything. It builds a structured filename from parts - date, steps, schedule, seed, genre, custom tags, and a counter - sanitizes it, and hands it to your save node as a path prefix. It's a small utility that quietly saves you a lot of "is this the good one?" scrolling.

It's clearly built for audio workflows (the default project_path is Ace-Step/313/ and the presets are Instrumental/Vocal/Master), but it works just as well for images - the parts are generic.

How it works

You give it a base_template (the start of the name, with Python strftime codes - %Y-%m-%d for the date), a project_path (nested subfolders under ComfyUI's output dir, auto-sanitized), and then toggle which optional bits get appended. The node joins the enabled parts with a separator (default " - ") and produces two outputs:

• full_path_prefix - the entire path, ready to feed into a Save node's filename field.
• filename_preview - the final filename as a string, so you can eyeball it or log it.

Everything that goes into the name gets sanitized - the source strips or escapes characters that break filesystems, and it preserves parentheses (useful for mode tags like (Custom Mode)).

The inputs that matter

• preset - Custom, Instrumental, Vocal, Master, Raw Output, AB Test. Presets override the manual toggles and pre-set the tags for standard MD workflows. Custom is the one to pick for full control; the mode_tag input is only active in Custom mode.
• base_template + project_path - the skeleton and the folder. Keep the date at the start for OS sorting, as the tooltip suggests.
• The include toggles - include_steps (appends e.g. 20S), include_schedule (scheduler/sigma info), include_seed (Seed_12345, JS-safe range), include_genre, include_counter (#0001).
• The values - steps, schedule_info (feed it from a scheduler's info string), seed, genre, custom_tag_1/2, counter_start (wire a counter node here). genre_max_length (default 40) truncates long genre strings.

debug_mode and enable_profiling are the usual console-noise controls.

The honest caveats

It's a string builder, not a saver - you still connect the output to a Save node. And "smart" is doing real work but modest work: it doesn't embed metadata, it just names files well. The presets are audio-flavored; if you're doing images you'll mostly live in Custom mode. The separator default of " - " produces nice names but spaces in filenames can annoy some tooling - switch to _ if that bites you.

Installing

It's part of MD Nodes:

cd path/to/ComfyUI/custom_nodes
git clone https://github.com/MDMAchine/ComfyUI_MD_Nodes.git
cd ComfyUI_MD_Nodes && pip install -r requirements.txt

Or via ComfyUI Manager (search MD Nodes), then restart. Standard pack caveat: the requirements drag in the audio stack and more, even though this node is pure string logic.

If your output folder is chaos, this is a twenty-second fix: date first, steps and seed appended, and suddenly every file is self-describing. That's a quality-of-life win you'll appreciate exactly when you go looking for that one render a month later.