Debug String _O

Straight answer up front: if you found Debug String _O and just want to see what a string contains, don't use this node. Use Debug Text _O from the same pack. Debug String _O still exists because it's a deprecated leftover - the pack keeps it around purely so old workflows don't break when they're loaded. It's the debug node for the pack's legacy string system, which ran on a custom STR type that modern ComfyUI nodes don't speak.

Here's the catch that makes it a trap for beginners: its input string is typed as STR, not the native STRING type. STR is a dict-wrapped value produced by the old string nodes - String _O, concat Strings _O, trim String _O from the same deprecated folder. Plug a normal Text _O output into it and it won't connect, because the types don't match. You'll sit there wondering why the wire snaps to nothing while the pack's own modern nodes would have just worked.

How it works

The deprecated file literally prints debugString: followed by the inner string value to the console, and returns nothing - it's an output node with no outputs, same dead-end behaviour as the modern debug nodes. So functionally it's identical to Debug Text _O, minus the prefix label, plus the incompatible input type. The implementation even predates the pack's current naming: this whole class is DebugString_deprecated, kept for backward compatibility and marked for eventual removal.

So the only reason to ever place it is compatibility. You load an old workflow that was built on the pack's previous string suite, it references Debug String _O, and ComfyUI drops it in for you so the graph still resolves. In that case, leave it alone and let the old graph run. If you're starting fresh, you have zero reason to reach for it.

The one input that matters

• string (STR) - the legacy dict-wrapped string. It only accepts output from the deprecated STR nodes. There's no prefix field, so multiple debug strings all print as debugString: with no way to tell them apart.

If you're already neck-deep in the old string suite and just want to see a value, it works - but honestly, the modern replacement is strictly better: Debug Text _O takes native STRING, adds a prefix label, and lives under O/debug/text instead of the deprecated folder.

Installing it

Part of the Quality of Life Suit pack (omar92/ComfyUI-QualityOfLifeSuit_Omar92). Install via ComfyUI Manager (search "Quality of Life Suit") or clone:

cd <ComfyUI>/custom_nodes
git clone https://github.com/omar92/ComfyUI-QualityOfLifeSuit_Omar92.git

Then restart ComfyUI - a browser reload won't do it. No models or extra dependencies. The pack's config.json defaults autoUpdate to true, so it can pull commits on startup; disable it there if you want the folder to stay put.

Common issues

• "The wire won't connect." Expected - STR doesn't match STRING. This is the #1 reason anyone lands on this page, and the fix is to switch to Debug Text _O.
• "I see debugString: but no value." The upstream STR node is empty. And remember: output goes to the terminal that launched ComfyUI, never the browser.
• It disappears after an update. The whole deprecated suite is on the chopping block. If this node vanishes from the menu one day, that's the pack doing what it warned about - the modern debug nodes are the safe home.

One sentence to remember: deprecated means "we kept it so old workflows still load," not "this is how you debug." Reach for Debug Text _O.