Claude Fable 5
Benefit
+1.12
Harm
0.00
Net Good
1.12
Verified benefit
0.00
History
Cumulative score
- Benefit
- Harm
- Net
Release
Status released. First dated 21 Jul 2026.
Event timeline
Claude Fable 5.1 solves Urquhart’s Cyphral Distich, a 370-year-old cipher
On 31 August 2026 Vals reported that Claude Fable 5.1 recovered Sir Thomas Urquhart’s 1653 Cyphral Distich in 44 minutes and then applied the same book-as-key rule to the longer Cyphral Octastich, leaving a nine-letter gap.
Conant, with Claude Fable 5, proves the mod-4 Kawauchi conjecture
On 21 July 2026 Jim Conant posted a proof that the Conway polynomial of an amphicheiral knot satisfies ∇_K ≡ f(z)f(−z) (mod 4), a strengthening he had conjectured after the integral Kawauchi conjecture failed. He credits Claude Fable 5 with help producing the proof.
Long, using Sol Pro and Fable 5, posts low-degree Gaussian Moments counterexamples
On 20 July 2026 Christopher D. Long posted explicit polynomials showing the Gaussian Moments conjecture fails in every dimension n≥3: a cubic in four variables found by GPT-5.6 Sol Pro, then a quartic in three variables found by Claude Fable 5. This is not a Jacobian-conjecture score and not a Clay problem.
Claude Fable 5 produces a presentation of Gal(Q̄₂/Q₂)
On 9 June 2026 David Roe elicited a Claude Fable 5 solution to Epoch’s open problem asking for a presentation of the absolute Galois group of the 2-adics. Epoch later accepted verifier output and noted a second, independent GPT-5.5 Pro solution. Epoch warns the verifier is short of a full proof on this problem.