Anthropic Reportedly Finishes Training Successor to Suspended Mythos 5 Model

Anthropic has reportedly finished training a more capable Mythos successor, according to AI watcher Andrew Curran. The company has not confirmed the model’s existence, name, or capabilities. Curran said the system could ship as Mythos 5.

1 or Mythos 6, or stay internal. His report came nine days after US export controls forced Anthropic to suspend Mythos 5 and Fable 5. Mythos Successor Emerges from Training Curran describes the supposed new system as stronger than Mythos 5.

However, he stressed uncertainty over its name and whether Anthropic would release it at all. “A new, more capable version of Mythos has emerged from training. I don’t know whether it will be called Mythos 5.

1 or Mythos 6, or if Anthropic will keep it internal to accelerate further development…” Curran wrote. Anthropic released Mythos 5 and Fable 5 on June 9 and lost them to the directive three days later.

Several still expect an iterative upgrade, partly because the model suspension order limits today’s lineup. Fable 5 ships with heavy safeguards for public use. Mythos 5 runs with fewer security restrictions through Project Glasswing, the firm’s vetted cybersecurity program.

Anthropic says about 50 partners have used early Mythos models to find more than 10,000 high- or critical-severity software flaws. Why the Suspension Does Not Stop Development Commerce Secretary Howard Lutnick sent the directive to Anthropic chief Dario Amodei on June 12, citing national security. A bipartisan group of lawmakers is pressing Commerce Secretary Howard Lutnick to explain the legal and technical rationales behind the decision to impose export controls on Anthropic’s new models.

@Dareasmunhoz has the story:https://t.co/Oou0YQT9zV pic.twitter.

com/PdMvp0U9N5— Punchbowl News (@PunchbowlNews) June 18, 2026 It barred every foreign national, including Anthropic’s own foreign-born staff, so the firm disabled both models worldwide. The government flagged a method for bypassing Fable 5’s safeguards. Anthropic reviewed the d