Reasoning Parsing (Dynamo) | NVIDIA Dynamo Documentation

Some models emit reasoning or thinking content separately from their final response. Dynamo can split that output into reasoning_content and normal assistant content by configuring --dyn-reasoning-parser on the backend worker.

This page covers parser names for the default Dynamo-native path. If Dynamo does not list a parser for your model, see Reasoning Parsing (Engine Fallback).

Prerequisites

To enable reasoning parsing, launch the backend worker with:

--dyn-reasoning-parser: select the reasoning parser from the supported list below

$ # <backend> can be sglang, trtllm, vllm, etc. based on your installation
$ python -m dynamo.<backend> --help

Some models need both a reasoning parser and a tool call parser. For supported tool call parser names, see Tool Call Parsing (Dynamo).

Supported Reasoning Parsers

The table below lists the currently supported reasoning parsers in Dynamo’s registry. The Upstream name column shows where the vLLM or SGLang parser name differs from Dynamo’s — relevant when using --dyn-chat-processor vllm or sglang (see Reasoning Parsing (Engine Fallback)). A blank upstream column means the same name works everywhere. Dynamo-only means no upstream parser exists for this format.

Parsers marked force-reasoning emit reasoning content from token one without requiring an explicit opening tag (<think>, etc.). All others require the opening tag to be present in the model output.

Parser Name	Models	Upstream name	Force-reasoning	Notes
`kimi_k25`	Kimi K2.5	Dynamo-only	Yes	`<think>...</think>` with force-reasoning
`qwen3`	Qwen3.5, QwQ-32B, Qwen3-Think, Qwen3-Coder		No	`<think>...</think>`
`deepseek_v4`	DeepSeek V4 Pro / Flash	vLLM: `deepseek_v4`; SGLang: `deepseek-v4`	No	`<think>...</think>`. Aliases: `deepseek-v4`, `deepseekv4`
`basic`	Generic CoT models	Dynamo-only	No	Plain `<think>...</think>`
`deepseek_r1`	DeepSeek R1, DeepSeek V3.1, DeepSeek V3.2		Yes	Pass explicitly for V3.1/V3.2 (no alias)
`gemma4`	Google Gemma 4 (thinking models)	vLLM: `gemma4`	No	`<\|channel>thought\n...<channel\|>` with `thought\n` role label stripped. Aliases: `gemma-4`
`glm45`	GLM-4.5, GLM-4.7	Dynamo-only	No	Alias for `nemotron_deci`. `<think>...</think>`
`gpt_oss`	gpt-oss-20b / -120b	Dynamo-only	No	Harmony channel reasoning format
`granite`	Granite 3.x		No	`Here's my thought process:` / `Here's my response:`
`kimi`	Kimi K2 Instruct / Thinking	Dynamo-only	No	`◁think▷...◁/think▷`
`minimax_append_think`	MiniMax M2 / M2.1	Dynamo-only	No	Implicit opening `<think>` prepended
`mistral`	Magistral		Yes	`[THINK]...[/THINK]`
`nemotron3`	Nemotron-3 / Mini	vLLM: `nemotron_v3`	Yes	Alias for `deepseek_r1`. Also accepts `nemotron_v3`
`nemotron_deci`	Nemotron-Super / -Ultra / -Deci, Llama-Nemotron	Dynamo-only	No	`<think>...</think>`
`nemotron_nano`	Nemotron-Nano	Dynamo-only	Yes	Alias for `deepseek_r1`
`step3`	Step-3 / Step-3-Reasoning	Dynamo-only	Yes	`<think>...</think>`

Common Parser Pairings

Some models need both parsers configured together. Common pairings include:

openai/gpt-oss-*: --dyn-tool-call-parser harmony --dyn-reasoning-parser gpt_oss
deepseek-ai/DeepSeek-V4-*: --dyn-tool-call-parser deepseek_v4 --dyn-reasoning-parser deepseek_v4
zai-org/GLM-4.7: --dyn-tool-call-parser glm47 --dyn-reasoning-parser glm45
moonshotai/Kimi-K2.5*: --dyn-tool-call-parser kimi_k2 --dyn-reasoning-parser kimi_k25
google/gemma-4-* thinking models: --dyn-tool-call-parser gemma4 --dyn-reasoning-parser gemma4 --custom-jinja-template examples/chat_templates/gemma4_tool.jinja
Qwen/Qwen3.5*: --dyn-tool-call-parser qwen3_coder --dyn-reasoning-parser qwen3
MiniMax M2.1 style outputs: --dyn-tool-call-parser minimax_m2 --dyn-reasoning-parser minimax_append_think

Tool Calling Interplay

Reasoning parsing happens before tool call parsing. If a model emits both reasoning content and tool calls, configure both parsers so Dynamo can first separate reasoning text and then parse tool calls from the remaining assistant output.