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On October 27, 2026, Mirendil released Fern, its first model pretrained from scratch, with a context length of up to 10M tokens, equivalent to roughly 500,000 lines of code or several days of agent work trajectories. The first version, Fern 0.1, underwent only short-round post-training; its architecture, training, and serving were all designed for 10M context, and next-token metrics continued to improve as context lengthened. It targets high-throughput work such as auditing data, reading training logs, and reading through agent trajectories, and lists six scenarios including work on larger repositories, agentic coding, AI research code, and debugging long logs. On the same day, another report stated that Fern 0.1 is a coding model with a context window of up to 10M tokens, equivalent to about 23 MB of code, or around 500,000 lines; Mirendil-Base was pretrained by a single researcher in 3.5 months, with a total compute cost of less than $10 million, AI agents wrote more than 99% of the code, and the training data came only from public sources; RULER single-needle retrieval was 100% at every length from 32K to 10M tokens, but Terminal Bench 4.0 was only 6.1% and SWE-Bench Verified was 73.4%. It is currently available only as hosted early access, with no open-source weights.
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Mirendil Releases Its First Model Fern 0.1, Supporting a 10M Token ContextDevelopments
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Mirendil releases Fern, its first model pretrained from scratch
Source:Shao Meng
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Oct 27
MarkTechPost
Mirendil Releases Its First Model Fern 0.1, Supporting a 10M Token Context
Mirendil has released its first model, Fern 0.1, a coding model trained from scratch with a context window of up to 10M tokens, equivalent to roughly 23 MB of code, or about 500,000 lines. Mirendil-Base was pretrained by a single researcher in 3.5 months, with a total compute cost of less than $10 million; AI agents wrote more than 99% of the code, and the training data came only from public sources. RULER single-needle retrieval scored 100% at every length from 32K to 10M tokens, but Terminal Bench 4.0 scored only 6.1%, and SWE-Bench Verified scored 73.4%. Currently only hosted early access is available, and the weights have not been open-sourced.
Shao Meng
Mirendil Releases Fern, Its First Model Pretrained from Scratch, Supporting 10M Token Context
Mirendil released Fern, its first model pretrained from scratch, with a context of up to 10M tokens, equivalent to roughly 500,000 lines of code (Megatron-LM scale) or several days of an agent's work trajectory. The first version, Fern 0.1, underwent only a short round of post-training; its architecture, training, and serving were all designed for a 10M context, and next-token metrics continue to improve as context length grows. It targets high-throughput work such as auditing data, reading training logs, and reading through agent trajectories, and lists six scenarios including work on larger repositories, agentic coding, AI research code, and long-log debugging.
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