[Linkpost] “Estimating GPT-6 Astra’s no-CoT Time Horizon” by Francis Rhys Ward, Dewi Gould
[Linkpost] “Estimating GPT-6 Astra’s no-CoT Time Horizon” by Francis Rhys Ward, Dewi Gould  
Podcast: LessWrong (30+ Karma)
Published On: Wed Sep 09 2026
Description: This is a link post. TL;DR: We run astra on the task-suite from Think Fast. GPT-6 Astra is close to saturation on our suite, meaning that giving a confident estimate of time horizons (TH) is more challenging.Our rough estimate is that Astra's 50% TH is in [8mins, 1 hour] and probably around 15-40 mins. This is inline with UKAISI's estimate of 30 minutes measured only on math.  Using data from 2019 to April 2026, in Think Fast our median prediction was that no-CoT THs could exceed 7 minutes by 2028. We estimated 30mins by the end of the decade.Astra clearly gets much higher performance on tasks that require serial reasoning, e.g., Arc-agi-1 and 2, hash, n-hop-look-up, causal-reasoning, sally-anne, all the puzzle tasks.There are limitations with our task suite: Ideally we would have more time-variation (especially longer times) in each specific benchmark, and more benchmarks with longer human completion times. We use the single-forward pass (31) and generation tasks (6) from the Think Fast suite, totalling 37 benchmarks. Notably we find that Astra gets >= 98% raw accuracy on 10 benchmarks (cf. GPT-5.5 saturates 4 benchmarks – see Appendix). As a result, the [...] ---Outline:(04:21) Commentary(05:22) Acknowledgements(05:34) Appendix(05:37) Per-benchmark time horizons(06:06) Sensitivity to fake benchmarks ablations(08:23) Raw benchmark performance(09:06) Table of TH results(10:28) Implementation caveats(11:23) GPT-6 Astra: per-benchmark 50% no-CoT time horizons (no filtering or hypothetical benchmarks)(13:16) GPT-5.5 vs GPT-6 Astra: no-CoT raw accuracy per benchmark(14:02) Math & science(14:21) Abstract reasoning(14:42) Puzzles(15:02) Language & strategy(15:21) SWE & cyber(15:41) Steganography(16:01) Sabotage & monitoring (TPR @1.5% FPR)(16:55) Including generation tasks(17:09) Reasoning token anchor(17:24) N-hop Task(17:44) Filler tokens --- First published: September 9th, 2026 Source: https://www.lesswrong.com/posts/ntKx9YHWCwxSeGbRB/estimating-gpt-6-astra-s-no-cot-time-horizon Linkpost URL:https://docs.google.com/document/d/1LsJh6ecdfONCSJVpbC44pz1JzcEs4_TM5HD0oihe_70/edit?tab=t.0 --- Narrated by TYPE III AUDIO. ---Images from the article:Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.