Inspect VST Plugin

Plugins are opaque. You load a compressor and you think you know its parameters, but the names, ranges, and value types that actually matter to the graph are hidden inside the plugin binary. VSTInspector is the flashlight: point it at a loaded plugin and it reads out everything the pack can see - every parameter, its type, its range, its current value - in a form a human can read and a machine can use.

You reach for this node the moment you load a plugin and have no idea what to type into VSTManualParameters, or when a parameter you set isn't sticking. It's the debug window for the whole ComfyUI-VST pipeline, and it's completely read-only - it never modifies the plugin. If you came looking for knobs, this isn't the node; the knobs live in VSTParameters (the dynamic widget one) and VSTManualParameters.

How it works

Under the hood it walks the plugin's parameter list via Pedalboard and classifies each one into the same three buckets the whole pack uses:

• Boolean - a toggle with true/false, like a bypass.
• Choice - a dropdown of up to 16 valid text values, like an algorithm selector.
• Numeric - a continuous slider with min/max (and a step if the plugin exposes one), like a mix knob or a room size.

For each it reads the units label, the current value, and the range, then formats everything into a human-readable summary. The same data is also dumped out as a structured schema in three flavors, so whatever downstream tool you're feeding has a version it can swallow.

Inputs and outputs

One input: plugin, straight from VSTLoader. Five outputs, and you'll mostly care about two of them:

• summary - a formatted, human-readable listing: plugin type, then each parameter with its units and [min - max] default: range or its choice options. Wire this into a Show Text node and you have your cheat sheet.
• parameter_names - a comma-separated string of every parameter name. This is the one that saves you from typos when you're filling in VSTManualParameters.
• parameter_schema - the typed schema object. This is what feeds the dynamic VSTParameters node.
• parameter_schema_dict / parameter_schema_json - the same schema as a Python dict and a JSON string, for custom scripting or just eyeballing the raw structure.

How to actually use it

Chain it right after VSTLoader: Load → Inspect. Run once, read the summary, copy exact parameter names from parameter_names, and paste them into VSTManualParameters. Parameter names here are case-sensitive and must match exactly - this node is how you get them right instead of guessing.

Installing it

Same pack as the rest of ComfyUI-VST - install it once and you get all five nodes. Via Manager, search "ComfyUI-VST", or:

cd ComfyUI/custom_nodes
git clone https://github.com/MuziekMagie/ComfyUI-VST.git
cd ComfyUI-VST
pip install -r requirements.txt

Restart ComfyUI after. The only dependency is pedalboard>=0.9.0, and the pack needs a ComfyUI build with the newer V3 API - on an old build none of these nodes will show up.

Common issues

• "Pedalboard library not installed" - the dependency didn't make it in; pip install "pedalboard>=0.9.0" into your ComfyUI environment.
• Ugly or cryptic parameter names - some plugins expose internal names rather than friendly ones. That's the plugin, not the node; copy what you see and use it verbatim.
• The summary looks empty - a plugin that reports no parameters will produce a header with nothing under it. Load a different one to sanity-check.

This is the cheapest node in the pack to reach for and the one that saves you the most guesswork. When a plugin is doing something unexpected, inspect it first.