diff --git a/examples/chat_template/tool_chat_template_deepseekv31.jinja b/examples/chat_template/tool_chat_template_deepseekv31.jinja
new file mode 100644
index 000000000..9149cb442
--- /dev/null
+++ b/examples/chat_template/tool_chat_template_deepseekv31.jinja
@@ -0,0 +1,91 @@
+{% if not add_generation_prompt is defined %}
+ {% set add_generation_prompt = false %}
+{% endif %}
+{% if not thinking is defined %}
+ {% set thinking = false %}
+{% endif %}
+{% set ns = namespace(is_first=false, is_tool=false, system_prompt='', is_first_sp=true, is_last_user=false) %}
+{%- for message in messages %}
+ {%- if message['role'] == 'system' %}
+ {%- if ns.is_first_sp %}
+ {% set ns.system_prompt = ns.system_prompt + message['content'] %}
+ {% set ns.is_first_sp = false %}
+ {%- else %}
+ {% set ns.system_prompt = ns.system_prompt + '\n\n' + message['content'] %}
+ {%- endif %}
+ {%- endif %}
+{%- endfor %}
+
+{% if tools is defined and tools is not none %}
+ {% set tool_ns = namespace(text='## Tools\nYou have access to the following tools:\n') %}
+ {% for tool in tools %}
+ {% set tool_ns.text = tool_ns.text + '\n### ' + tool.function.name + '\nDescription: ' + tool.function.description + '\n\nParameters: ' + (tool.function.parameters | tojson) + '\n' %}
+ {% endfor %}
+ {% set tool_ns.text = tool_ns.text + "\nIMPORTANT: ALWAYS adhere to this exact format for tool use:\n<|tool▁calls▁begin|><|tool▁call▁begin|>tool_call_name<|tool▁sep|>tool_call_arguments<|tool▁call▁end|>{{additional_tool_calls}}<|tool▁calls▁end|>\n\nWhere:\n\n- `tool_call_name` must be an exact match to one of the available tools\n- `tool_call_arguments` must be valid JSON that strictly follows the tool's Parameters Schema\n- For multiple tool calls, chain them directly without separators or spaces\n" %}
+ {% set ns.system_prompt = ns.system_prompt + '\n\n' + tool_ns.text %}
+{% endif %}
+
+{{ bos_token }}{{ ns.system_prompt }}
+{%- for message in messages %}
+ {%- if message['role'] == 'user' %}
+ {%- set ns.is_tool = false -%}
+ {%- set ns.is_first = false -%}
+ {%- set ns.is_last_user = true -%}
+ {{'<|User|>' + message['content']}}
+ {%- endif %}
+ {%- if message['role'] == 'assistant' and message['tool_calls'] is defined and message['tool_calls'] is not none %}
+ {%- if ns.is_last_user %}
+ {{'<|Assistant|>'}}
+ {%- endif %}
+ {%- set ns.is_last_user = false -%}
+ {%- set ns.is_first = false %}
+ {%- set ns.is_tool = false -%}
+ {%- for tool in message['tool_calls'] %}
+ {%- if not ns.is_first %}
+ {%- if message['content'] is none %}
+ {{'<|tool▁calls▁begin|><|tool▁call▁begin|>'+ tool['function']['name'] + '<|tool▁sep|>' + tool['function']['arguments'] + '<|tool▁call▁end|>'}}
+ {%- else %}
+ {{message['content'] + '<|tool▁calls▁begin|><|tool▁call▁begin|>' + tool['function']['name'] + '<|tool▁sep|>' + tool['function']['arguments'] + '<|tool▁call▁end|>'}}
+ {%- endif %}
+ {%- set ns.is_first = true -%}
+ {%- else %}
+ {{'<|tool▁call▁begin|>'+ tool['function']['name'] + '<|tool▁sep|>' + tool['function']['arguments'] + '<|tool▁call▁end|>'}}
+ {%- endif %}
+ {%- endfor %}
+ {{'<|tool▁calls▁end|><|end▁of▁sentence|>'}}
+ {%- endif %}
+ {%- if message['role'] == 'assistant' and (message['tool_calls'] is not defined or message['tool_calls'] is none) %}
+ {%- if ns.is_last_user %}
+ {{'<|Assistant|>'}}
+ {%- if message['prefix'] is defined and message['prefix'] and thinking %}
+ {{''}}
+ {%- else %}
+ {{''}}
+ {%- endif %}
+ {%- endif %}
+ {%- set ns.is_last_user = false -%}
+ {%- if ns.is_tool %}
+ {{message['content'] + '<|end▁of▁sentence|>'}}
+ {%- set ns.is_tool = false -%}
+ {%- else %}
+ {%- set content = message['content'] -%}
+ {%- if '' in content %}
+ {%- set content = content.split('', 1)[1] -%}
+ {%- endif %}
+ {{content + '<|end▁of▁sentence|>'}}
+ {%- endif %}
+ {%- endif %}
+ {%- if message['role'] == 'tool' %}
+ {%- set ns.is_last_user = false -%}
+ {%- set ns.is_tool = true -%}
+ {{'<|tool▁output▁begin|>' + message['content'] + '<|tool▁output▁end|>'}}
+ {%- endif %}
+{%- endfor -%}
+{%- if add_generation_prompt and ns.is_last_user and not ns.is_tool %}
+ {{'<|Assistant|>'}}
+ {%- if not thinking %}
+ {{''}}
+ {%- else %}
+ {{''}}
+ {%- endif %}
+{% endif %}
diff --git a/python/sglang/srt/function_call/deepseekv31_detector.py b/python/sglang/srt/function_call/deepseekv31_detector.py
new file mode 100644
index 000000000..2045d8daa
--- /dev/null
+++ b/python/sglang/srt/function_call/deepseekv31_detector.py
@@ -0,0 +1,222 @@
+import json
+import logging
+import re
+from typing import List
+
+from sglang.srt.entrypoints.openai.protocol import Tool
+from sglang.srt.function_call.base_format_detector import BaseFormatDetector
+from sglang.srt.function_call.core_types import (
+ StreamingParseResult,
+ StructureInfo,
+ ToolCallItem,
+ _GetInfoFunc,
+)
+from sglang.srt.function_call.ebnf_composer import EBNFComposer
+from sglang.srt.function_call.utils import _is_complete_json
+
+logger = logging.getLogger(__name__)
+
+
+class DeepSeekV31Detector(BaseFormatDetector):
+ """
+ Detector for DeepSeek V3 model function call format.
+
+ The DeepSeek V3 format uses special Unicode tokens to delimit function calls
+ with JSON code blocks for arguments.
+
+ Format Structure:
+ ```
+ <|tool▁calls▁begin|><|tool▁call▁begin|>{function_name}<|tool▁sep|>{json_arguments}<|tool▁calls▁end|><|end▁of▁sentence|>
+ ```
+ Examples:
+ ```
+ <|tool▁calls▁begin|><|tool▁call▁begin|>get_current_weather<|tool▁sep|>{"location": "Tokyo"}<|tool▁call▁end|><|tool▁call▁begin|>get_current_weather<|tool▁sep|>{"location": "Paris"}<|tool▁call▁end|><|tool▁calls▁end|><|end▁of▁sentence|>
+ ```
+
+ Key Components:
+ - Tool Calls Section: Wrapped between `<|tool▁calls▁begin|>` and `<|tool▁calls▁end|>`
+ - Individual Tool Call: Wrapped between `<|tool▁call▁begin|>` and `<|tool▁call▁end|>`
+ - Function Declaration: `<|tool▁call▁begin|>{function_name}<|tool▁sep|>`
+ - Arguments: JSON code block between `<|tool▁sep|>` and `<|tool▁call▁end|>`
+ - Supports multiple tool calls
+
+ Reference: https://www.modelscope.cn/models/deepseek-ai/DeepSeek-V3.1
+ """
+
+ def __init__(self):
+ super().__init__()
+ self.bot_token = "<|tool▁calls▁begin|>"
+ self.eot_token = "<|tool▁calls▁end|>"
+ self.func_call_regex = r"<|tool▁call▁begin|>.*?<|tool▁call▁end|>"
+ self.func_detail_regex = (
+ r"<|tool▁call▁begin|>(.*)<|tool▁sep|>(.*)<|tool▁call▁end|>"
+ )
+ self._last_arguments = ""
+ self.current_tool_id = -1
+
+ def has_tool_call(self, text: str) -> bool:
+ """Check if the text contains a deepseek format tool call."""
+ return self.bot_token in text
+
+ def detect_and_parse(self, text: str, tools: List[Tool]) -> StreamingParseResult:
+ """
+ One-time parsing: Detects and parses tool calls in the provided text.
+
+ :param text: The complete text to parse.
+ :param tools: List of available tools.
+ :return: ParseResult indicating success or failure, consumed text, leftover text, and parsed calls.
+ """
+ idx = text.find(self.bot_token)
+ normal_text = text[:idx].strip() if idx != -1 else text
+ if self.bot_token not in text:
+ return StreamingParseResult(normal_text=normal_text, calls=[])
+ match_result_list = re.findall(self.func_call_regex, text, re.DOTALL)
+ calls = []
+ try:
+ for match_result in match_result_list:
+ # Get function name
+ func_detail = re.search(self.func_detail_regex, match_result, re.DOTALL)
+ func_name = func_detail.group(1)
+ func_args = func_detail.group(2)
+ func_args = json.loads(func_args)
+ # construct match_result for parse_base_json
+ match_result = {"name": func_name, "parameters": func_args}
+ calls.extend(self.parse_base_json(match_result, tools))
+ return StreamingParseResult(normal_text=normal_text, calls=calls)
+ except Exception as e:
+ logger.error(f"Error in detect_and_parse: {e}")
+ # return the normal text if parsing fails
+ return StreamingParseResult(normal_text=text)
+
+ def parse_streaming_increment(
+ self, new_text: str, tools: List[Tool]
+ ) -> StreamingParseResult:
+ """
+ Streaming incremental parsing tool calls for DeepSeekV3 format.
+ """
+ self._buffer += new_text
+ current_text = self._buffer
+
+ # Check if we have a tool call (either the start token or individual tool call)
+ has_tool_call = (
+ self.bot_token in current_text or "<|tool▁call▁begin|>" in current_text
+ )
+
+ if not has_tool_call:
+ self._buffer = ""
+ for e_token in [self.eot_token, "<|tool▁call▁end|>"]:
+ if e_token in new_text:
+ new_text = new_text.replace(e_token, "")
+ return StreamingParseResult(normal_text=new_text)
+
+ if not hasattr(self, "_tool_indices"):
+ self._tool_indices = self._get_tool_indices(tools)
+
+ calls: list[ToolCallItem] = []
+ try:
+ partial_match = re.search(
+ pattern=r"<|tool▁call▁begin|>(.*)<|tool▁sep|>(.*)<|tool▁call▁end|>",
+ string=current_text,
+ flags=re.DOTALL,
+ )
+ if partial_match:
+ func_name = partial_match.group(1).strip()
+ func_args_raw = partial_match.group(2).strip()
+
+ # Initialize state if this is the first tool call
+ if self.current_tool_id == -1:
+ self.current_tool_id = 0
+ self.prev_tool_call_arr = []
+ self.streamed_args_for_tool = [""]
+
+ # Ensure we have enough entries in our tracking arrays
+ while len(self.prev_tool_call_arr) <= self.current_tool_id:
+ self.prev_tool_call_arr.append({})
+ while len(self.streamed_args_for_tool) <= self.current_tool_id:
+ self.streamed_args_for_tool.append("")
+
+ if not self.current_tool_name_sent:
+ calls.append(
+ ToolCallItem(
+ tool_index=self.current_tool_id,
+ name=func_name,
+ parameters="",
+ )
+ )
+ self.current_tool_name_sent = True
+ # Store the tool call info for serving layer completions endpoint
+ self.prev_tool_call_arr[self.current_tool_id] = {
+ "name": func_name,
+ "arguments": {},
+ }
+ else:
+ argument_diff = (
+ func_args_raw[len(self._last_arguments) :]
+ if func_args_raw.startswith(self._last_arguments)
+ else func_args_raw
+ )
+
+ if argument_diff:
+ calls.append(
+ ToolCallItem(
+ tool_index=self.current_tool_id,
+ name=None,
+ parameters=argument_diff,
+ )
+ )
+ self._last_arguments += argument_diff
+ self.streamed_args_for_tool[
+ self.current_tool_id
+ ] += argument_diff
+
+ if _is_complete_json(func_args_raw):
+ # Update the stored arguments
+ try:
+ parsed_args = json.loads(func_args_raw)
+ self.prev_tool_call_arr[self.current_tool_id][
+ "arguments"
+ ] = parsed_args
+ except json.JSONDecodeError:
+ pass
+
+ # Find the end of the current tool call and remove only that part from buffer
+ tool_call_end_pattern = (
+ r"<|tool▁call▁begin|>.*?<|tool▁call▁end|>"
+ )
+ match = re.search(
+ tool_call_end_pattern, current_text, re.DOTALL
+ )
+ if match:
+ # Remove the completed tool call from buffer, keep any remaining content
+ self._buffer = current_text[match.end() :]
+ else:
+ self._buffer = ""
+
+ result = StreamingParseResult(normal_text="", calls=calls)
+ self.current_tool_id += 1
+ self._last_arguments = ""
+ self.current_tool_name_sent = False
+ return result
+
+ return StreamingParseResult(normal_text="", calls=calls)
+
+ except Exception as e:
+ logger.error(f"Error in parse_streaming_increment: {e}")
+ return StreamingParseResult(normal_text=current_text)
+
+ def structure_info(self) -> _GetInfoFunc:
+ return lambda name: StructureInfo(
+ begin="<|tool▁call▁begin|>" + name + "<|tool▁sep|>",
+ end="<|tool▁call▁end|>",
+ trigger="<|tool▁call▁begin|>" + name + "<|tool▁sep|>",
+ )
+
+ def build_ebnf(self, tools: List[Tool]):
+ return EBNFComposer.build_ebnf(
+ tools,
+ sequence_start_token=self.bot_token,
+ sequence_end_token=self.eot_token,
+ tool_call_separator="",
+ call_rule_fmt='"<|tool▁call▁begin|>{name}<|tool▁sep|>{arguments_rule}<|tool▁call▁end|>"',
+ function_format="json",
+ )
diff --git a/python/sglang/srt/function_call/function_call_parser.py b/python/sglang/srt/function_call/function_call_parser.py
index 97e9814bf..18fe488e4 100644
--- a/python/sglang/srt/function_call/function_call_parser.py
+++ b/python/sglang/srt/function_call/function_call_parser.py
@@ -10,6 +10,7 @@ from sglang.srt.entrypoints.openai.protocol import (
from sglang.srt.function_call.base_format_detector import BaseFormatDetector
from sglang.srt.function_call.core_types import ToolCallItem
from sglang.srt.function_call.deepseekv3_detector import DeepSeekV3Detector
+from sglang.srt.function_call.deepseekv31_detector import DeepSeekV31Detector
from sglang.srt.function_call.glm4_moe_detector import Glm4MoeDetector
from sglang.srt.function_call.gpt_oss_detector import GptOssDetector
from sglang.srt.function_call.kimik2_detector import KimiK2Detector
@@ -37,6 +38,7 @@ class FunctionCallParser:
"qwen25": Qwen25Detector,
"mistral": MistralDetector,
"deepseekv3": DeepSeekV3Detector,
+ "deepseekv31": DeepSeekV31Detector,
"pythonic": PythonicDetector,
"kimi_k2": KimiK2Detector,
"qwen3_coder": Qwen3CoderDetector,