Hermes 4 405B
Hermes 4 is a large-scale reasoning model built on Meta-Llama-3.1-405B and released by Nous Research.
Specifications
| Lab | Nous Research |
|---|---|
| Context window | 131.1K tokens |
| Input price | $1.00/1M |
| Output price | $3.00/1M |
| Release | Aug 2025 |
Strengths
- Hybrid reasoning mode auto-decides when to think deeply
- Strong instruction following and tool use
- Open-weight on Llama 3.1 405B base
- Uncensored no refusal for controversial topics
Weaknesses
- Based on older Llama 3.1 architecture
- Very large model slow and expensive to run
- Less competitive on raw benchmarks vs latest models
Best for
- Complex multi-step reasoning
- Creative and uncensored writing
- Research and experimentation
- Tool-use and agentic workflows
In Depth: Hermes 4 405B
Summary
Hermes 4 405B is an AI model from Nous Research.
Released in Aug 2025. It currently appears in the Overall category on LMRank. It takes text input and produces text output, with a context window of 131.1K tokens. Input pricing is $1.00 per 1M tokens and output is $3.00 per 1M tokens on OpenRouter.