🔱 Gemini Instruct

Gemini Instruct is the quietest node in the Artha-Gemini pack, and also the one with the least excuse for drama: it doesn't call any API and needs no key. Its entire job is to build a system-instruction string that you feed into other Gemini nodes' system_instruction slots. Think of it as a reusable prompt template that lets you customize how every other node in the pack behaves.

That's more useful than it sounds. Most of the pack's nodes ship with a good built-in agent - Vision has its structured captioner, Cloth has its garment-lister, and so on. But the moment you want one of them to behave differently - "describe this image in the style of a film location scout" - you need a way to inject your own instructions. That's the slot this node feeds.

How it works

Three multiline text inputs, no logic beyond string assembly:

• role - who the agent is. Defaults to You are an intelligent ai assistant.
• task - what it should do. Defaults to Your task is to...
• instructions - any extra guidance.

The node strips double quotes from all three fields (a small safety touch), then assembles them into the pack's system-instruction format: Role: ... on its own line, then Task: ..., then the instructions. The output type is ARTHAINSTRUCT, the custom type that the pack's API nodes accept in their system_instruction inputs - so it's designed to plug straight in.

No API block here, no model, no temperature. You're just shaping a string.

Inputs and outputs

• role, task, instructions - the three text fields above.
• Output: system_instruction (ARTHAINSTRUCT).

Connect the output to the system_instruction input on Gemini Vision, Motion, Prompter, Imagen, or any other pack node that exposes that optional slot. If a node has that input and you don't wire it, it falls back to its bundled agent - so Instruct is purely additive: wire it in when you want control, leave it out when the default is fine.

Installing it

Via ComfyUI Manager (search Artha-Gemini) or:

cd ComfyUI/custom_nodes
git clone https://github.com/Cyrostar/ComfyUI-Artha-Gemini
cd ComfyUI-Artha-Gemini
pip install -r requirements.txt

No model downloads, no API key, no cost - this node never leaves your machine.

Where people get burned

The main failure mode is expecting it to do more than it does. Instruct doesn't prompt Gemini itself; it just produces the instruction text. If you wire Instruct straight to a KSampler or expect it to generate anything, nothing happens. It's a text producer for other nodes - the dependency flows through the pack's system_instruction inputs.

Second, remember it overrides the built-in agent. If you wire in a vague role and task, you're replacing a tuned, purpose-built instruction with your own, often worse, one. A good pattern is to start without Instruct, see how the default agent performs, and only add custom instructions when you know what you want changed. And a small practical note: the ARTHAINSTRUCT output only matches ARTHAINSTRUCT-typed inputs, so it won't plug into arbitrary STRING slots elsewhere in ComfyUI.