diff --git a/python/sglang/srt/parser/reasoning_parser.py b/python/sglang/srt/parser/reasoning_parser.py
index cd346625a..00c26196b 100644
--- a/python/sglang/srt/parser/reasoning_parser.py
+++ b/python/sglang/srt/parser/reasoning_parser.py
@@ -25,11 +25,13 @@ class BaseReasoningFormatDetector:
         think_end_token: str,
         force_reasoning: bool = False,
         stream_reasoning: bool = True,
+        tool_start_token: Optional[str] = None,
         continue_final_message: bool = False,
         previous_content: str = "",
     ):
         self.think_start_token = think_start_token
         self.think_end_token = think_end_token
+        self.tool_start_token = tool_start_token
         self._in_reasoning = force_reasoning
         self.stream_reasoning = stream_reasoning
 
@@ -66,7 +68,21 @@ class BaseReasoningFormatDetector:
             self.think_end_token not in processed_text
             and self.think_end_token not in self.previous_content
         ):
-            # Assume reasoning was truncated before `</think>` token
+            # Check for tool_start_token interruption
+            if (
+                in_reasoning
+                and self.tool_start_token is not None
+                and self.tool_start_token in processed_text
+            ):
+                # Find the first occurrence of tool_start_token and split there
+                tool_idx = processed_text.find(self.tool_start_token)
+                reasoning_text = processed_text[:tool_idx].strip()
+                # Preserve tool_start_token in normal text
+                normal_text = processed_text[tool_idx:]
+                return StreamingParseResult(
+                    normal_text=normal_text, reasoning_text=reasoning_text
+                )
+            # Assume reasoning was truncated before end token
             return StreamingParseResult(reasoning_text=processed_text)
 
         # Extract reasoning content
@@ -96,9 +112,12 @@ class BaseReasoningFormatDetector:
         current_text = self._buffer
 
         # If the current text is a prefix of the think token, keep buffering
+        tokens_to_check = [self.think_start_token, self.think_end_token]
+        if self.tool_start_token:
+            tokens_to_check.append(self.tool_start_token)
         if any(
             token.startswith(current_text) and token != current_text
-            for token in [self.think_start_token, self.think_end_token]
+            for token in tokens_to_check
         ):
             return StreamingParseResult()
 
@@ -124,6 +143,17 @@ class BaseReasoningFormatDetector:
 
         # Continue with reasoning content
         if self._in_reasoning:
+            # Check for tool_start_token interruption
+            if self.tool_start_token and self.tool_start_token in current_text:
+                tool_idx = current_text.find(self.tool_start_token)
+                reasoning_text = current_text[:tool_idx]
+                # Preserve tool_start_token in normal text
+                normal_text = current_text[tool_idx:]
+                self._buffer = ""
+                self._in_reasoning = False
+                return StreamingParseResult(
+                    normal_text=normal_text, reasoning_text=reasoning_text
+                )
             if self.stream_reasoning:
                 # Stream the content immediately
                 self._buffer = ""
@@ -238,6 +268,29 @@ class KimiDetector(BaseReasoningFormatDetector):
         )
 
 
+class Glm45Detector(BaseReasoningFormatDetector):
+    """
+    Detector for GLM-4.5 models.
+    Assumes reasoning format:
+      (<think>)*(.*)</think>
+
+    GLM-4.5 uses `<tool_call>` as the tool start token to switch from reasoning mode to normal mode.
+
+    Args:
+        stream_reasoning (bool): If False, accumulates reasoning content until the end tag.
+            If True, streams reasoning content as it arrives.
+    """
+
+    def __init__(self, stream_reasoning: bool = True, force_reasoning: bool = False):
+        super().__init__(
+            "<think>",
+            "</think>",
+            force_reasoning=force_reasoning,
+            stream_reasoning=stream_reasoning,
+            tool_start_token="<tool_call>",
+        )
+
+
 class GptOssDetector(BaseReasoningFormatDetector):
     """
     Detector for T4-style reasoning format (GPT-OSS), using the HarmonyParser.
@@ -375,7 +428,7 @@ class ReasoningParser:
     DetectorMap: Dict[str, Type[BaseReasoningFormatDetector]] = {
         "deepseek-r1": DeepSeekR1Detector,
         "deepseek-v3": Qwen3Detector,
-        "glm45": Qwen3Detector,
+        "glm45": Glm45Detector,
         "gpt-oss": GptOssDetector,
         "kimi": KimiDetector,
         "kimi_k2": Qwen3Detector,
diff --git a/test/registered/parser/test_reasoning_parser.py b/test/registered/parser/test_reasoning_parser.py
index 5c28066c7..b76f85342 100644
--- a/test/registered/parser/test_reasoning_parser.py
+++ b/test/registered/parser/test_reasoning_parser.py
@@ -3,6 +3,7 @@ import unittest
 from sglang.srt.parser.reasoning_parser import (
     BaseReasoningFormatDetector,
     DeepSeekR1Detector,
+    Glm45Detector,
     KimiDetector,
     Qwen3Detector,
     ReasoningParser,
@@ -313,6 +314,158 @@ class TestKimiDetector(CustomTestCase):
         self.assertEqual(result.normal_text, "answer")
 
 
+class TestGlm45Detector(CustomTestCase):
+    """Test cases for GLM45 detector with tool interruption support."""
+
+    def setUp(self):
+        self.detector = Glm45Detector()
+
+    def test_init(self):
+        """Test Glm45Detector initialization."""
+        self.assertEqual(self.detector.think_start_token, "<think>")
+        self.assertEqual(self.detector.think_end_token, "</think>")
+        self.assertEqual(self.detector.tool_start_token, "<tool_call>")
+        self.assertFalse(self.detector._in_reasoning)
+        self.assertTrue(self.detector.stream_reasoning)
+
+    def test_detect_and_parse_normal_reasoning(self):
+        """Test parsing normal reasoning block without tool interruption."""
+        text = "<think>Let me think about this step by step</think>The answer is 42."
+        result = self.detector.detect_and_parse(text)
+        self.assertEqual(result.reasoning_text, "Let me think about this step by step")
+        self.assertEqual(result.normal_text, "The answer is 42.")
+
+    def test_detect_and_parse_tool_interrupt(self):
+        """
+        Test parsing with tool interruption.
+
+        GLM45 can interrupt reasoning with tool token (<tool_call>) without closing </think>.
+        Should split at the first occurrence of tool_start_token using find().
+        """
+        text = "<think>I need to think<tool_call>tool call data"
+        result = self.detector.detect_and_parse(text)
+        self.assertEqual(result.reasoning_text, "I need to think")
+        self.assertEqual(result.normal_text, "<tool_call>tool call data")
+
+    def test_detect_and_parse_multiple_tool_calls_find(self):
+        """
+        Test that find() finds the FIRST occurrence of tool_start_token.
+
+        If multiple tool calls exist in buffer, should split at the first one.
+        """
+        text = "<think>thinking<tool_call>first tool<tool_call>second tool<tool_call>final tool"
+        result = self.detector.detect_and_parse(text)
+        # Should split at the first <tool_call>
+        self.assertEqual(result.reasoning_text, "thinking")
+        self.assertEqual(
+            result.normal_text,
+            "<tool_call>first tool<tool_call>second tool<tool_call>final tool",
+        )
+
+    def test_detect_and_parse_truncated_reasoning(self):
+        """
+        Test truncated reasoning without tool or end tag.
+
+        Should return all content as reasoning_text.
+        """
+        text = "<think>This is incomplete"
+        result = self.detector.detect_and_parse(text)
+        self.assertEqual(result.reasoning_text, "This is incomplete")
+        self.assertEqual(result.normal_text, "")
+
+    def test_detect_and_parse_normal_text_only(self):
+        """Test parsing text without reasoning block."""
+        text = "Just the answer without any reasoning."
+        result = self.detector.detect_and_parse(text)
+        self.assertEqual(result.normal_text, text)
+        self.assertEqual(result.reasoning_text, "")
+
+    def test_streaming_normal_flow(self):
+        """Test streaming with normal reasoning flow."""
+        # Start reasoning
+        result1 = self.detector.parse_streaming_increment("<think>")
+        self.assertEqual(result1.normal_text, "")
+        self.assertEqual(result1.reasoning_text, "")
+        self.assertTrue(self.detector._in_reasoning)
+
+        # Reasoning content
+        result2 = self.detector.parse_streaming_increment("thinking...")
+        self.assertEqual(result2.normal_text, "")
+        self.assertEqual(result2.reasoning_text, "thinking...")
+
+        # End reasoning
+        result3 = self.detector.parse_streaming_increment("</think>answer")
+        self.assertEqual(result3.normal_text, "answer")
+        self.assertEqual(result3.reasoning_text, "")
+        self.assertFalse(self.detector._in_reasoning)
+
+    def test_streaming_tool_interrupt_split_tokens(self):
+        """
+        Test streaming with tool interruption where tool token is split across chunks.
+
+        This tests the buffer prefix logic that prevents partial emission of tool token.
+        """
+        # Start reasoning
+        self.detector.parse_streaming_increment("<think>")
+
+        # Add reasoning
+        result1 = self.detector.parse_streaming_increment("thinking")
+        self.assertEqual(result1.reasoning_text, "thinking")
+
+        # Send partial tool token (should be buffered, not emitted)
+        result2 = self.detector.parse_streaming_increment("<tool_call>")
+        # Tool token is in buffer, causing switch to normal mode
+        self.assertEqual(result2.reasoning_text, "")
+        self.assertEqual(result2.normal_text, "<tool_call>")
+        self.assertFalse(self.detector._in_reasoning)
+
+        # Send tool args
+        result3 = self.detector.parse_streaming_increment("tool args")
+        self.assertEqual(result3.reasoning_text, "")
+        self.assertEqual(result3.normal_text, "tool args")
+
+    def test_streaming_no_stream_reasoning(self):
+        """Test streaming without stream_reasoning enabled."""
+        detector = Glm45Detector(stream_reasoning=False)
+
+        # Start reasoning
+        detector.parse_streaming_increment("<think>")
+
+        # Reasoning content is buffered and not returned yet
+        result = detector.parse_streaming_increment("thinking")
+        self.assertEqual(result.reasoning_text, "")
+        self.assertEqual(result.normal_text, "")
+
+        # Tool interruption should still work - flushes buffered reasoning
+        # Note: buffer preserves original text including <think> tag
+        result = detector.parse_streaming_increment("<tool_call>tool call")
+        self.assertEqual(result.reasoning_text, "<think>thinking")
+        self.assertEqual(result.normal_text, "<tool_call>tool call")
+
+    def test_streaming_empty_reasoning_with_tool(self):
+        """Test empty reasoning block followed by tool call."""
+        result1 = self.detector.parse_streaming_increment("<think>")
+        result2 = self.detector.parse_streaming_increment("<tool_call>tool call")
+        self.assertEqual(result2.reasoning_text, "")
+        self.assertEqual(result2.normal_text, "<tool_call>tool call")
+
+    def test_forced_reasoning_mode(self):
+        """Test GLM45 with force_reasoning=True."""
+        detector = Glm45Detector(force_reasoning=True)
+
+        # Without start token, should still be in reasoning mode
+        text = "This is reasoning"
+        result = detector.detect_and_parse(text)
+        self.assertEqual(result.reasoning_text, "This is reasoning")
+        self.assertEqual(result.normal_text, "")
+
+        # Tool interruption should work with forced reasoning
+        text = "More reasoning<tool_call>tool call"
+        result = detector.detect_and_parse(text)
+        self.assertEqual(result.reasoning_text, "More reasoning")
+        self.assertEqual(result.normal_text, "<tool_call>tool call")
+
+
 class TestReasoningParser(CustomTestCase):
     def test_init_valid_model(self):
         """Test initialization with valid model types."""
@@ -325,6 +478,9 @@ class TestReasoningParser(CustomTestCase):
         parser = ReasoningParser("kimi")
         self.assertIsInstance(parser.detector, KimiDetector)
 
+        parser = ReasoningParser("glm45")
+        self.assertIsInstance(parser.detector, Glm45Detector)
+
     def test_init_invalid_model(self):
         """Test initialization with invalid model type."""
         with self.assertRaises(ValueError) as context:
@@ -383,6 +539,32 @@ class TestReasoningParser(CustomTestCase):
         parser = ReasoningParser("qwen3", stream_reasoning=True)
         self.assertTrue(parser.detector.stream_reasoning)
 
+    def test_glm45_tool_interruption(self):
+        """Test GLM45 tool interruption through ReasoningParser API."""
+        parser = ReasoningParser("glm45")
+
+        # Non-streaming: tool interrupt
+        reasoning, normal = parser.parse_non_stream(
+            "<think>thinking<tool_call>tool call"
+        )
+        self.assertEqual(reasoning, "thinking")
+        self.assertEqual(normal, "<tool_call>tool call")
+
+        # Streaming: tool interrupt
+        parser = ReasoningParser("glm45")
+        chunks = ["<think>", "reasoning", "<tool_call>", "tool args"]
+        all_reasoning = ""
+        all_normal = ""
+        for chunk in chunks:
+            reasoning, normal = parser.parse_stream_chunk(chunk)
+            if reasoning:
+                all_reasoning += reasoning
+            if normal:
+                all_normal += normal
+
+        self.assertEqual(all_reasoning, "reasoning")
+        self.assertEqual(all_normal, "<tool_call>tool args")
+
 
 class TestIntegrationScenarios(CustomTestCase):
     """Integration tests for realistic usage scenarios."""