Instructor 👨🏻‍🏫

This is a template system for prompts built around explicit placeholders - you write a prompt with markers like [SUBJECT] or [STYLE] sitting in it, and then fill each one in through the node's own interface rather than rewriting the whole prompt by hand every time. It's a classic Mad-Libs approach to prompting: lock down the structure once, swap only the parts that change.

Like this pack's Prompt Builder, the whole interaction lives inside the node's custom on-canvas UI rather than through standard typed sockets - which is why the schema shows no declared inputs at all. Nothing to plug in; you interact with it directly on the canvas.

How it works

Per the pack's README, you define placeholder tokens inside your prompt text and then fill them in through a simple interface, with the node also handling organization, history tracking, and template management around those saved prompt structures - so you're not just filling blanks once, you're building a reusable library of prompt skeletons you can return to. This is a genuinely different workflow from a straight YAML-templated approach like Prompt Styler: Styler picks a whole pre-written template for you, while Instructor is closer to writing your own reusable prompt scaffolding and deciding what varies each time.

The inputs and outputs that matter

There's nothing in required or optional - everything happens in the node's own interface.

Output: instruction, a single STRING - the filled-in prompt, ready to feed into a CLIP Text Encode or into another iTools node downstream.

Installing it

Via ComfyUI Manager: search "iTools" or "ComfyUI-iTools," install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/MohammadAboulEla/ComfyUI-iTools

then restart. No special dependencies for this node.

Troubleshooting

Placeholders aren't being recognized. The pattern the node expects, per the README's own examples, is square brackets around a plain word - [SUBJECT], [STYLE]. If you've written something outside that convention (curly braces, a different bracket style, lowercase-only tokens if the node expects uppercase), it likely won't be picked up as a fill-in point.

Output string is empty even though you've filled in placeholders. Check that the node's own fill-in interface actually registered your entries - since there's no typed socket triggering this, a value that "looks" entered in the UI but wasn't committed (a field you clicked into but didn't confirm) can leave the final instruction output blank or stale.

You've lost track of which template you're currently editing. The node keeps history and template management built in per the README, but that's a within-session convenience, not a guarantee against losing work across a full ComfyUI restart. For anything you can't afford to lose, save the finished, filled-in prompt out with Prompt Saver once you're happy with it, rather than relying solely on this node's own history.

You want randomized variation, not manual fill-in. Instructor is built for deliberate, manual template completion. If what you actually want is automatic variety from a word list, this pack's Line Loader plus a substitution step is the better fit for that specific job.