PSA - comfyUI now support system prompt for Text Generate (Qwen2.1 related)

They just merged it https://github.com/Comfy-Org/ComfyUI/pull/16442 TL;DR: it's a prompt enhancer that you can use to improve Qwen Image 2.1 prompt Usage: Download these qwen3.5_9b_qwen_image , t2i for text, i2i for edit. They are not text encoders, don't use them as one. https://huggingface.co/Comfy-Org/Qwen-Image-2.1/tree/main/text_encoders Load Clip , type qwen_image > Generate text For System prompt slot. Copy & paste official Qwen 2.1 system prompt (t2i/edit) from https://github.com/QwenLM/Qwen-Image-2.1/tree/fb7ae1d1f9611cd91524d03c53c5246b36ac8577/prompt_rewrite/prompts Recommend settings: T2I (Temperature: 1.0, Top_P: 0.95, Top_K: 20, Max_length: 16,256, Presence Penalty: 1.5) / EDIT (Temperature: 1.0, Top_P: 0.95, Top_K: 20, Max_length: 24,000, Presence Penalty: 0.0) - Thinking=On/ Use_default_template=ON Use Image Batch node to connect more than 1 image Tip: (Experimental: only try this after you've tested the full Prompt Enhancer with thinking workflow) If you just want a usable prompt that works with clear user instructions. Add this near the end of the official system prompt, right before "The user's edit instruction to rewrite is:" ## Immediate Final Output Do not output analysis, reasoning, planning, self-checks, commentary, headings, or markdown. The very first characters of your response must be exactly: {"rewritten_prompt":" Continue directly inside the rewritten_prompt JSON string and complete the required JSON object. Output nothing before the opening {. And in user prompt, also add Return the final JSON immediately. Begin exactly with {"rewritten_prompt":" And set thinking= off This will TRY TO skip the reasoning process and quickly output a somewhat decent rewritten prompt. And it only needs ~500 tokens instead of 5000-6000 (obviously, a full prompt enhancer with thinking is still better, but it's not always worth x10 tokens) submitted by /u/fallengt [link] [comments]

Source: r/StableDiffusion | 2026-09-22

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