vllm/vllm/reasoning/qwen3_reasoning_parser.py
0xNullPath 3c62d28bb9 [Model] Support SeedOss Reason Parser (#24263)
Signed-off-by: Yan Lu <luyan@nvidia.com>
Co-authored-by: Michael Goin <mgoin64@gmail.com>
Signed-off-by: yewentao256 <zhyanwentao@126.com>
2025-10-03 13:35:54 -07:00

73 lines
2.7 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from typing import Optional, Union
from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
ResponsesRequest)
from vllm.reasoning.abs_reasoning_parsers import ReasoningParserManager
from vllm.reasoning.basic_parsers import BaseThinkingReasoningParser
@ReasoningParserManager.register_module("qwen3")
class Qwen3ReasoningParser(BaseThinkingReasoningParser):
"""
Reasoning parser for the Qwen3 model.
The Qwen3 model uses <think>...</think> tokens to denote reasoning text
within its output. The model provides a strict switch to disable reasoning
output via the 'enable_thinking=False' parameter. This parser extracts the
reasoning content enclosed by <think> and </think> tokens from the model's
output.
"""
@property
def start_token(self) -> str:
"""The token that starts reasoning content."""
return "<think>"
@property
def end_token(self) -> str:
"""The token that ends reasoning content."""
return "</think>"
def extract_reasoning_content(
self, model_output: str, request: Union[ChatCompletionRequest,
ResponsesRequest]
) -> tuple[Optional[str], Optional[str]]:
"""
Extract reasoning content from the model output.
Qwen3 has stricter requirements - it needs both start and end tokens
to be present, unlike other models that work with just the end token.
For text <think>abc</think>xyz:
- 'abc' goes to reasoning_content
- 'xyz' goes to content
Returns:
tuple[Optional[str], Optional[str]]: reasoning content and content
"""
# Check if the model output contains both <think> and </think> tokens.
if (self.start_token not in model_output
or self.end_token not in model_output):
return None, model_output
# Check if the <think> is present in the model output, remove it
# if it is present.
model_output_parts = model_output.partition(self.start_token)
model_output = model_output_parts[2] if model_output_parts[
1] else model_output_parts[0]
# Check if the model output contains the </think> tokens.
# If the end token is not found, return the model output as is.
if self.end_token not in model_output:
return None, model_output
# Extract reasoning content from the model output.
reasoning_content, _, content = model_output.partition(self.end_token)
final_content = content or None
return reasoning_content, final_content