From 55b6a9b11dffecdd65a3ccd5eb6a1b3a178c96dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jukka=20Sepp=C3=A4nen?=
 <40791699+kijai@users.noreply.github.com>
Date: Fri, 14 Aug 2026 22:17:18 +0300
Subject: [PATCH] Fix thinking handling (#15611)

---
 comfy/text_encoders/gemma4.py |  9 ++++++---
 comfy_extras/nodes_textgen.py | 10 ++++------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/comfy/text_encoders/gemma4.py b/comfy/text_encoders/gemma4.py
index 61bc3a3f0..da116ab27 100644
--- a/comfy/text_encoders/gemma4.py
+++ b/comfy/text_encoders/gemma4.py
@@ -6,6 +6,7 @@ import numpy as np
 from tokenizers import Tokenizer
 from dataclasses import dataclass
 import math
+import re
 
 from comfy import sd1_clip
 import comfy.model_management
@@ -1624,11 +1625,13 @@ class Gemma4SDTokenizer(Gemma4_Tokenizer, sd1_clip.SDTokenizer):
 
     def decode(self, token_ids, **kwargs):
         text = super().decode(token_ids, skip_special_tokens=False)
-        # Translate thinking channel markers to standard <think>/</think> tags
+        # Only a close that ends a thought channel becomes </think>: generation primed with
+        # another channel leaves its opener in the prompt, so its close is not reasoning.
+        text = re.sub(r"<\|channel>thought\n(.*?)<channel\|>", r"<think>\n\1</think>", text, flags=re.DOTALL)
         text = text.replace("<|channel>thought\n", "<think>\n")
-        text = text.replace("<channel|>", "</think>")
         # Strip remaining special tokens
-        text = text.replace("<turn|>", "").replace("<eos>", "").strip()
+        text = re.sub(r"<\|channel>\w*\n?|<channel\|>|<\|turn>\w*\n?|<turn\|>", "", text)
+        text = text.replace("<eos>", "").strip()
         return text
 
 
diff --git a/comfy_extras/nodes_textgen.py b/comfy_extras/nodes_textgen.py
index 40004652c..ef5858a7d 100644
--- a/comfy_extras/nodes_textgen.py
+++ b/comfy_extras/nodes_textgen.py
@@ -256,12 +256,10 @@ class TextGenerateLTX2Prompt(TextGenerate):
 
         out = super().execute(clip, formatted_prompt, max_length, sampling_mode, image=image, thinking=thinking, use_default_template=use_default_template, video=video, audio=audio)
 
-        text = out.args[0]
-        text = re.sub(r"<think>.*?</think>", "", text, flags=re.DOTALL)
-        if "</think>" in text:  # unclosed/truncated reasoning: keep what follows the last close
-            text = text.rsplit("</think>", 1)[-1]
-        text = re.sub(r"</?think>|<\|channel>\w*\n?|<channel\|>|<\|turn>\w*\n?", "", text).strip()
-        return io.NodeOutput(text)
+        # Drop reasoning, including a block left unclosed by max_length. Both system prompts ask
+        # for the original prompt back when there is nothing to give; empty conditions on nothing.
+        text = re.sub(r"<think>.*?(?:</think>|$)", "", out.args[0], flags=re.DOTALL).strip()
+        return io.NodeOutput(text or prompt)
 
 
 class TextgenExtension(ComfyExtension):