Deprecated · Sampling Trace Mask

Sampling Trace Mask is the probe that watches a MASK wire. It records the mask's shape, dtype, value range, and statistics, then passes the mask through absolutely unchanged. Think of it as a voltmeter you clamp onto a wire - it reads, it doesn't touch.

Masks are where a lot of subtle workflow breakage hides. A mask that's supposed to be soft 0–1 grayscale can end up as a hard binary after a threshold node, or normalized to 0–255, or full of NaN after some math node. This probe will tell you the range and mean in one glance, so you can catch "my mask is suddenly all zeros" before it silently ruins your compositing. It's the kind of check you can also do by saving and opening the image, except this happens inside the graph without a file round-trip.

It's part of the pack's hidden probes family - deprecated and hidden from normal search in 0.4.0, kept alive for saved-workflow compatibility and internal diagnostics. Like its siblings, it does not start sampling trace capture by itself.

Inputs and outputs

• mask (required, MASK) - the branch to inspect.
• label (optional, STRING) - a name for the probe; useful when several share the panel.
• trace_session (optional, TRACE_SESSION) - connect one to store the summary into a run's evidence; leave it unwired and the probe just emits a live event.
• Output: mask, unchanged.

Install

The pack's standard install:

git clone https://github.com/ILcrowe/ComfyUI-SamplingTrace-Inspector.git ComfyUI/custom_nodes/ComfyUI-SamplingTrace-Inspector

or ComfyUI Manager → "Sampling Trace", restart. No extra dependencies or model files.

Where people get burned

• It won't show up in search. Deprecated by design; it loads from old saved workflows only.
• No tracing begins. Probes record and pass through - they don't start a sampling trace run.
• Unwired trace_session means no persistence. Live event only, unless you connect the session.

Honest take: you'll likely never need this in a new graph. If you're resurrecting an old workflow and a mask misbehaves, it's a genuinely useful stethoscope.