Hermes 4 405B
Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research. It introduces a hybrid reasoning mode, where the model can choose to deliberate internally with <think>...</think> traces or respond directly, offering flexibility between speed and depth. Users can control the reasoning behaviour with the `reasoning` `enabled` boolean. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#enable-reasoning-with-default-config) The model
Context window
This model accepts 131K tokens in one request (~98K words of text).
What fits in one request
- FitsShort documentAbout 1,500 words of text
- FitsLong documentAbout 37K words of text
- Won't fitSmall codebaseAbout 150K words of text
- Won't fitFull novelAbout 375K words of text
Specifications
Context size, pricing, and release info in one place.
- Context window
- 131,072 tokens (131K)
- Speed tier
- deep
- Provider
- Nous Research
- Release date
- Aug 2025
Capabilities
See which features this model supports, such as vision, tools, and streaming.
- Extended thinking
- Shows its chain-of-thought reasoning
- Supported
- Streaming
- Returns tokens as they are generated
- Supported
- Vision
- Accepts image inputs alongside text
- Not supported
- Tool use
- Can call external tools and APIs
- Not supported
- Function calling
- Structured function call interface
- Not supported
- Web search
- Can browse the web during a request
- Not supported
- Batch API
- Process many requests asynchronously
- Not supported
- Prompt caching
- Reuse repeated prompt prefixes cheaply
- Not supported
Best for
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Compare Hermes 4 405B
Open a side-by-side comparison with one click.
- Hermes 4 405B vs Amazon Titan Text Express
Hermes 4 405B has 212% larger context window
- Hermes 4 405B vs Amazon Titan Text Lite
Hermes 4 405B has 212% larger context window
- Hermes 4 405B vs Amazon Titan Text Premier
Hermes 4 405B has 212% larger context window
- Hermes 4 405B vs Claude Instant
Hermes 4 405B has 31% larger context window
- Hermes 4 405B vs Anthropic Claude
Hermes 4 405B has 31% larger context window
- Hermes 4 405B vs Codellama 34b Instruct
Hermes 4 405B has 3100% larger context window
Frequently asked questions
Short answers about context size and how this model behaves.
More from Nous Research
Other models by Nous Research in our catalog.
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