Qwen 3.5 Chat Template Release with 21 Bug Fixes for Agent Workflows

A developer has released a patched chat template for Qwen 3.5 models, fixing 21 bugs encountered during agentic workflows. This is a drop-in replacement for the official template, requiring only a swap of the chat_template.jinja file.

Key Fixes

The developer specifically ran Qwen 3.5 35B for agentic workflows and addressed the following major issues:

• Tool Calling Crash: Fixed a crash related to arguments | items (referenced as HF discussion #4).
• Tool/Think Block Leak: <tool_call> content no longer leaks into <think> blocks, with auto-disable thinking when tools are active.
• Parallel Tool Calls: Calls are now properly separated with \n\n delimiters.
• Deep Agent Loops: Prevents crashes after 5+ tool hops.
• Unknown Role Handling: Roles like 'planner' and 'critic' now gracefully fall back instead of causing a crash.
• Streaming Parsers: Provides clean XML boundaries for streaming.
• Configurable Truncation: Allows setting a maximum character limit for large tool arguments and responses.
• Developer Role Support: Adds support for roles like 'Claude Code', 'Codex', and 'OpenCode'.

A full list of all 21 fixes is available in the project's README.

Configuration

The template includes configurable variables. They can be set via command-line arguments:

--chat-template-kwargs '{"enable_thinking":true,"auto_disable_thinking_with_tools":true,"max_tool_response_chars":8192}'

Compatibility & Testing

The template has been tested on the following platforms with the specified minimum versions:

• llama.cpp (b4242+)
• Open WebUI (v0.4.8+)
• vLLM (v0.6.4+)
• Ollama (v0.5.0+)
• LM Studio (v0.3.5+)
• Text Generation WebUI

It is compatible with all Qwen 3.5 models (35B, 27B, 14B, 9B, 4B, and the Coder series) and is backward-compatible with Qwen3 32B.

Source and License

The template is available for download on HuggingFace at barubary/qwen3.5-barubary-attuned-chat-template. It is released under the Apache 2.0 license, and the developer welcomes feedback and bug reports.