From 1193f13181a21f69706c221a44200ed857cd6cf8 Mon Sep 17 00:00:00 2001
From: Xinyuan Tong <115166877+JustinTong0323@users.noreply.github.com>
Date: Tue, 30 Sep 2025 17:44:44 -0700
Subject: [PATCH] fix: KimiK2Detector Improve tool call ID parsing with regex
 (#10972)

---
 .../srt/function_call/kimik2_detector.py      | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/python/sglang/srt/function_call/kimik2_detector.py b/python/sglang/srt/function_call/kimik2_detector.py
index 4f39433a6..ff29e7faa 100644
--- a/python/sglang/srt/function_call/kimik2_detector.py
+++ b/python/sglang/srt/function_call/kimik2_detector.py
@@ -50,6 +50,11 @@ class KimiK2Detector(BaseFormatDetector):
 
         self._last_arguments = ""
 
+        # Robust parser for ids like "functions.search:0" or fallback "search:0"
+        self.tool_call_id_regex = re.compile(
+            r"^(?:functions\.)?(?P<name>[\w\.]+):(?P<index>\d+)$"
+        )
+
     def has_tool_call(self, text: str) -> bool:
         """Check if the text contains a KimiK2 format tool call."""
         return self.bot_token in text
@@ -76,14 +81,18 @@ class KimiK2Detector(BaseFormatDetector):
             tool_calls = []
             for match in function_call_tuples:
                 function_id, function_args = match
-                function_name = function_id.split(".")[1].split(":")[0]
-                function_idx = int(function_id.split(".")[1].split(":")[1])
+                m = self.tool_call_id_regex.match(function_id)
+                if not m:
+                    logger.warning("Unexpected tool_call_id format: %s", function_id)
+                    continue
+                function_name = m.group("name")
+                function_idx = int(m.group("index"))
 
                 logger.info(f"function_name {function_name}")
 
                 tool_calls.append(
                     ToolCallItem(
-                        tool_index=function_idx,  # Use the call index in the response, not tool position
+                        tool_index=function_idx,
                         name=function_name,
                         parameters=function_args,
                     )
@@ -128,7 +137,11 @@ class KimiK2Detector(BaseFormatDetector):
                 function_id = match.group("tool_call_id")
                 function_args = match.group("function_arguments")
 
-                function_name = function_id.split(".")[1].split(":")[0]
+                m = self.tool_call_id_regex.match(function_id)
+                if not m:
+                    logger.warning("Unexpected tool_call_id format: %s", function_id)
+                    return StreamingParseResult(normal_text="", calls=calls)
+                function_name = m.group("name")
 
                 # Initialize state if this is the first tool call
                 if self.current_tool_id == -1: