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Mirendil's Fern 0.1 holds a 10M-token context and keeps 100% single-needle retrieval at full length, but multi-hop QA falls to 45%

AspireAI community · Mirendil
Mirendil introduced Fern on October 26, 2026: its first model, pretrained from scratch with a context window of up to 10M tokens (about 23 MiB of code, roughly half a million lines). On the company's own RULER run, Fern holds 100% on single-needle retrieval from 32K all the way to 10M tokens, 90% on multi-key retrieval and 100% on multi-key with all needles at 10M, while multi-hop QA (HotpotQA) sits at 65% from 32K and drops to 45% at 10M. On agentic coding the company reports 44.2% on DeepSWE v1.1, 73.4% on SWE-bench Verified and 76.5% on SWE-bench Pro v2 Hard. The honest limitation: these are vendor-run numbers, the model is not yet publicly accessible, and the 10M-token cells average only 20 examples.
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