AibSu/qwen3-enhanced-chat-template

Enhanced Chat Template for Qwen3.6

Based on froggeric/Qwen-Fixed-Chat-Templates with additional hardening.

Drop-in Jinja2 template that fixes 9 bugs from the official Qwen3.6 template and adds dynamic thinking toggle and defensive type checking.

What's Fixed

#	Bug	Impact
1	No item is not mapping guard	C++ engines (llama.cpp/LM Studio) crash
2	add_vision_id undefined access	Strict engines crash
3	developer role rejected	OpenAI-compatible API fails
4	Missing video_url key	Video input ignored
5	raise_exception on tool-only chains	Agent frameworks crash (LangChain/AutoGen/Claude Code)
6	Solo <think tag not handled	Parsing errors
7	Empty thinking blocks rendered	Wastes context tokens
8	Tool call missing name check	Malformed output
9	Tool call arguments not validated	Silent corruption

New Features

• Dynamic thinking toggle: Insert <|think_on|> / <|think_off|> in any message to switch per-turn
• Thinking state machine: ns_flags.enable_thinking persists across all messages
• developer role support: Fully compatible with OpenAI API
• Enhanced error messages: All exceptions include diagnostic context
• Tool call validation: Name presence + arguments type + message ordering
• video_url support: Video inputs via video_url key detected

Usage

vLLM

chat_template: /path/to/qwen3.6/chat_template.jinja

llama.cpp / LM Studio

Place chat_template.jinja alongside your model files.

Dynamic Thinking Toggle

messages = [
    {"role": "system", "content": "You are helpful. <|think_off|>"},
    {"role": "user", "content": "What is 2+2?"},           # no thinking
    {"role": "assistant", "content": "4"},
    {"role": "user", "content": "<|think_on|> Prove Fermat's theorem"}  # thinking ON
]

vLLM Template Parameters

response = client.chat.completions.create(
    model="Qwen3.6-27B-FP8",
    messages=messages,
    extra_body={
        "chat_template_kwargs": {
            "enable_thinking": False,    # disable thinking
            "preserve_thinking": True     # keep thinking blocks in history
        }
    }
)

Compatibility

Engine	Status
vLLM >= 0.6	Tested (primary)
llama.cpp	Compatible
LM Studio	Compatible
Ollama	Compatible
SGLang	Compatible

Related

• GitHub: GeerMrc/qwen3-enhanced-chat-template — full documentation (EN/CN), optimization details, client guide
• ModelScope: MaricZg/qwen3-enhanced-chat-template
• Upstream: froggeric/Qwen-Fixed-Chat-Templates