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Hermes 4 405B

Nous Research

Released
August 6, 2025
Data date
September 8, 2026
Benchmark-Meta-Score
Unavailable
No independent results
Speed
41.6 tokens/s
Output throughput
Price
Input · Output / 1M tokens
Input
Text
Output
Text

Hermes 4 405B combines a visible reasoning mode with direct answers and structured outputs. The open dense Llama 3.1 model has 405 billion parameters, a 131,072-token context, and tool-call support.

Nous Research describes Hermes 4 as an update to the 405B tier of Hermes 3 and lists five million post-training examples plus 56 billion training tokens. The weights use the Llama 3.1 Community License, not MIT or Apache 2.0.

Specifications and access

SpecificationValue and source
Weights
Open weightsSource
Access
API, LocalSource
Parameters
405BSource
Context window
131,072 tokensSource
License
Llama 3.1 Community LicenseSource
Parameters
405 BSource
Architecture
dense Llama 3.1 decoder-only transformer, 126 layersSource
Input
TextSource
Output
TextSource
Reasoning mode
hybrid mode; model can emit explicit <think> reasoning or answer in non-reasoning modeSource
Tool calling
Structured output
Post-training samples
5,000,000Source
Post-training tokens
60 B (The technical report's 56B figure is retained separately for the reported training setup.)Source
Training tokens
56 BSource
Training context
16,384 tokensSource