Fern 0.1 Benchmarks, Specifications & Availability

Fern 0.1

Explore Fern 0.1 from Mirendil: published specifications, source-linked vendor benchmarks, independent evaluator coverage and recorded pricing when available.

Published specifications

Provider: Mirendil
Access: Proprietary
License: Not published
Context window: 10000000
Total parameters: Not published
Active parameters: Not published
Released: 2026-10-26
Modalities: text
Family: Fern

Announcement · Website

Model notes

Mirendil says Fern 0.1 is Mirendil-Base after a short round of post-training, with up to 10M input-context tokens and text/code input. The publisher gives a 100B–500B parameter range; exact total and active counts are unpublished. Access is listed as coming soon; an official Hugging Face search found no exact released weights. License, price, API ID and output limit remain unknown. The publisher separately tested the pretraining-only Mirendil-Base on RULER, not Fern 0.1: at 10M tokens, single needle 100%, multi-key retrieval 90%, multi-key all needles 100%, variable-tracking recall 100% and HotpotQA 45%, each based on 20 examples. Do not transfer those base results to Fern 0.1; the full 32K–10M grid appears in the linked announcement.

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Pricing · OpenRouter

No OpenRouter pricing is recorded for this model. Missing rates are not free.

Official / vendor benchmarks

Default headline records. Own-vendor, peer-vendor and third-party provenance remain visible in evidence; configurations may differ.

Official / vendor headline scores; expand evidence for every record
Benchmark / evaluator	Headline score	Evidence
DeepSWE v1.1 (Mirendil OpenCode)	44.2%unknown effort	All 1 recorded result & sources 44.2% · raw 44.2 % Headline · unknown effort · Own vendor Source/record date: 2026-10-27 Harness: Mirendil vendor run, OpenCode, one attempt. Published 26 October 2026; actual execution date, agent version, token budget and model effort unpublished. Distinct from other vendor or evaluator harnesses. https://mirendil.com/news/introducing-fern/
Terminal-Bench 4.0 (Mirendil OpenCode)	6.1%unknown effort	All 1 recorded result & sources 6.1% · raw 6.1 % Headline · unknown effort · Own vendor Source/record date: 2026-10-27 Harness: Mirendil vendor run, OpenCode, one attempt. Published 26 October 2026; actual execution date, agent version, token budget and model effort unpublished. Distinct from other vendor or evaluator harnesses. https://mirendil.com/news/introducing-fern/
SWE Atlas Codebase QnA (Mirendil OpenCode)	53.2%unknown effort	All 1 recorded result & sources 53.2% · raw 53.2 % Headline · unknown effort · Own vendor Source/record date: 2026-10-27 Harness: Mirendil vendor run, OpenCode, one attempt. Published 26 October 2026; actual execution date, agent version, token budget and model effort unpublished. Distinct from other vendor or evaluator harnesses. https://mirendil.com/news/introducing-fern/
SWE-bench Pro v2 Hard (Mirendil OpenCode)	76.5%unknown effort	All 1 recorded result & sources 76.5% · raw 76.5 % Headline · unknown effort · Own vendor Source/record date: 2026-10-27 Harness: Mirendil vendor run, OpenCode, one attempt. Published 26 October 2026; actual execution date, agent version, token budget and model effort unpublished. Distinct from other vendor or evaluator harnesses. https://mirendil.com/news/introducing-fern/
SWE-bench Verified (Mirendil OpenCode)	73.4%unknown effort	All 1 recorded result & sources 73.4% · raw 73.4 % Headline · unknown effort · Own vendor Source/record date: 2026-10-27 Harness: Mirendil vendor run, OpenCode, one attempt. Published 26 October 2026; actual execution date, agent version, token budget and model effort unpublished. Distinct from other vendor or evaluator harnesses. https://mirendil.com/news/introducing-fern/

Independent evaluators

Evaluator harnesses are distinct from vendor measurements. Missing coverage is not a failed test.

No independent evaluator results are recorded for this model.

Read how we select and source scores or the comparison guide.