MD: Advanced Seed Generator

ComfyUI's built-in seed widget has a quirk that bites everyone eventually: it only changes when ComfyUI wants it to, and the native "randomize" behavior lives inside the widget rather than the graph. MD_AdvancedSeedGenerator is a proper graph-level seed source with five modes, an offset, and an output that tells you the exact seed it used.

The design goal is spelled out in the source: everything stays inside JavaScript's safe integer range (0 to 9,007,199,254,740,991), so the seed you see is the seed that ran - no precision drift.

The inputs

• seed - the base. 0 is fine if you're randomizing; your favorite seed if you're iterating.
• action - the mode, and the part that makes this node more than a widget wrapper:
  • Fixed - output is seed + offset. Fully reproducible.
  • Randomize - crypto-random number. The tooltip's recommendation for exploration.
  • Increment / Decrement - seed + offset ± 1, wrapping. Step through variations without touching the base.
  • System Time - the current nanosecond timestamp. A near-guaranteed-unique seed every run, useful for "never the same thing twice" batch runs.
• seed_offset - add or subtract without editing the base. The tooltip's pattern is the good one: keep the base fixed at 100 and sweep offset 1, 2, 3 for controlled variation. Applied in every mode except System Time.

Outputs

seed (INT - wire into your KSampler) and seed_str (STRING - same value as text, for embedding in metadata or filenames so you can reproduce a render later from its saved info).

One subtle behavior worth knowing: Randomize and System Time force the node to re-run every queue (the source makes IS_CHANGED return a fresh value each time), while Fixed/Increment/Decrement only execute when inputs change. That's the caching behavior you want - random modes must never be cached, deterministic ones should be.

Installing it

Part of MD Nodes (MDMAchine/ComfyUI_MD_Nodes). ComfyUI Manager → search MD_Nodes → Install, restart, or:

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

Restart ComfyUI. Python 3.10+, GPL v3, pure Python.

Common issues

The thing people trip on is expecting Increment to step between runs the way widget seeds do. It doesn't carry state - it computes deterministically from seed + offset + 1 on the inputs you give it. If you want a sequence of different seeds across a batch, sweep the offset from outside (a counter node, an LFO, another graph source). Also note that the native widget's "control after generate" is deliberately disabled on the seed input, so the randomization happens through the action menu, not the little shuffle arrow you might be used to.