From fdd24276edcdbf3fa0cafad56ede25e98f9dd022 Mon Sep 17 00:00:00 2001
From: Xunpeng Xiao <124695565+tangefly@users.noreply.github.com>
Date: Sun, 14 Dec 2025 00:20:33 +0800
Subject: [PATCH] [feat] support new function call value (#9610)

Co-authored-by: Yaowei Zheng <hiyouga@buaa.edu.cn>
---
 src/llamafactory/data/formatter.py | 55 +++++++++++++++++++-----------
 src/llamafactory/data/template.py  |  8 ++++-
 2 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/src/llamafactory/data/formatter.py b/src/llamafactory/data/formatter.py
index 9b527a7e..d13bb858 100644
--- a/src/llamafactory/data/formatter.py
+++ b/src/llamafactory/data/formatter.py
@@ -97,31 +97,46 @@ class FunctionFormatter(StringFormatter):
     @override
     def apply(self, **kwargs) -> SLOTS:
         content: str = kwargs.pop("content")
-        thought_words, thought = kwargs.pop("thought_words", None), None
-        if thought_words and len(thought_words) == 2:
-            regex = re.compile(rf"{re.escape(thought_words[0])}(.*?){re.escape(thought_words[1])}", re.DOTALL)
-            thought = re.search(regex, content)
+        thought_words = kwargs.pop("thought_words", None)
+        tool_call_words = kwargs.pop("tool_call_words", None)
 
-        if thought:
-            content = content.replace(thought.group(0), "")
+        def _parse_functions(json_content: str) -> list["FunctionCall"]:
+            try:
+                tool_calls = json.loads(json_content)
+                if not isinstance(tool_calls, list):  # parallel function call
+                    tool_calls = [tool_calls]
 
-        functions: list[FunctionCall] = []
-        try:
-            tool_calls = json.loads(content)
-            if not isinstance(tool_calls, list):  # parallel function call
-                tool_calls = [tool_calls]
+                return [FunctionCall(tc["name"], json.dumps(tc["arguments"], ensure_ascii=False)) for tc in tool_calls]
+            except json.JSONDecodeError:
+                raise RuntimeError(f"Invalid JSON format in function message: {str([content])}.")
 
-            for tool_call in tool_calls:
-                functions.append(
-                    FunctionCall(tool_call["name"], json.dumps(tool_call["arguments"], ensure_ascii=False))
-                )
+        tool_call_match = None
+        if tool_call_words and len(tool_call_words) == 2:
+            tool_call_regex = re.compile(
+                rf"{re.escape(tool_call_words[0])}(.*?){re.escape(tool_call_words[1])}", re.DOTALL
+            )
+            tool_call_match = re.search(tool_call_regex, content)
 
-        except json.JSONDecodeError:
-            raise RuntimeError(f"Invalid JSON format in function message: {str([content])}.")  # flat string
+        if tool_call_match is None:
+            thought_match = None
+            if thought_words and len(thought_words) == 2:
+                regex = re.compile(rf"{re.escape(thought_words[0])}(.*?){re.escape(thought_words[1])}", re.DOTALL)
+                thought_match = re.search(regex, content)
 
-        function_str = self.tool_utils.function_formatter(functions)
-        if thought:
-            function_str = thought.group(0) + function_str
+            if thought_match:
+                json_part = content.replace(thought_match.group(0), "")
+            else:
+                json_part = content
+
+            functions = _parse_functions(json_part)
+            function_str = self.tool_utils.function_formatter(functions)
+            if thought_match:
+                function_str = thought_match.group(0) + function_str
+        else:
+            thought_content = content.replace(tool_call_match.group(0), "")
+            functions = _parse_functions(tool_call_match.group(1))
+            function_str = self.tool_utils.function_formatter(functions)
+            function_str = thought_content + function_str
 
         return super().apply(content=function_str)
 
diff --git a/src/llamafactory/data/template.py b/src/llamafactory/data/template.py
index 36a4d43b..c611632f 100644
--- a/src/llamafactory/data/template.py
+++ b/src/llamafactory/data/template.py
@@ -49,6 +49,7 @@ class Template:
     default_system: str
     stop_words: list[str]
     thought_words: tuple[str, str]
+    tool_call_words: tuple[str, str]
     efficient_eos: bool
     replace_eos: bool
     replace_jinja_template: bool
@@ -156,7 +157,9 @@ class Template:
             elif message["role"] == Role.OBSERVATION:
                 elements += self.format_observation.apply(content=message["content"])
             elif message["role"] == Role.FUNCTION:
-                elements += self.format_function.apply(content=message["content"], thought_words=self.thought_words)
+                elements += self.format_function.apply(
+                    content=message["content"], thought_words=self.thought_words, tool_call_words=self.tool_call_words
+                )
             else:
                 raise NotImplementedError("Unexpected role: {}".format(message["role"]))
 
@@ -471,6 +474,7 @@ def register_template(
     default_system: str = "",
     stop_words: Optional[list[str]] = None,
     thought_words: Optional[tuple[str, str]] = None,
+    tool_call_words: Optional[tuple[str, str]] = None,
     efficient_eos: bool = False,
     replace_eos: bool = False,
     replace_jinja_template: bool = False,
@@ -522,6 +526,7 @@ def register_template(
         default_system=default_system,
         stop_words=stop_words or [],
         thought_words=thought_words or ("<think>\n", "\n</think>\n\n"),
+        tool_call_words=tool_call_words or ("<tool_call>", "</tool_call>"),
         efficient_eos=efficient_eos,
         replace_eos=replace_eos,
         replace_jinja_template=replace_jinja_template,
@@ -583,6 +588,7 @@ def parse_template(tokenizer: "PreTrainedTokenizer") -> "Template":
         default_system=default_system,
         stop_words=[],
         thought_words=("<think>\n", "\n</think>\n\n"),
+        tool_call_words=("<tool_call>", "</tool_call>"),
         efficient_eos=False,
         replace_eos=False,
         replace_jinja_template=False,