Anthropic Launches Claude Fable 5 at Half the Price of Mythos Preview — Benchmarks Top All Rivals

What Claude Fable 5 Is

Fable 5 is Anthropic’s astir susceptible publically disposable model. In Tuesday’s release, the institution says it leads connected astir each tested AI benchmarks, with peculiar spot successful bundle engineering, cognition work, technological research, and long-context tasks. Anthropic notes that the longer and much analyzable a task, the larger Fable 5’s vantage implicit its earlier models.

Pricing is acceptable astatine $10 per cardinal input tokens and $50 per cardinal output tokens. That is little than fractional the outgo of Claude Mythos Preview. Developers tin entree the exemplary done the Claude API utilizing the drawstring claude-fable-5.

Early Testing Results

The numbers from aboriginal testers are specific. Stripe reported that Fable 5 compressed months of engineering enactment into days, completing a codebase-wide migration crossed a 50-million-line Ruby codebase successful a azygous day. The aforesaid task would person required a afloat engineering squad much than 2 months to decorativeness by hand.

A illustration comparing FrontierCode benchmark results shows Claude Fable 5 outperforming Claude Opus 4.8 and GPT-5.5 successful coding accuracy arsenic task costs increase. Image source: Anthropic’s Claude Fable 5 and Claude Mythos 5 announcement connected June 9, 2026.

IMC said Fable 5 passed their trading investigation evaluations crossed factual lookup, conceptual reasoning, root-cause analysis, and expected-value analysis. On Hebbia’s Finance Benchmark for senior-level reasoning, Fable 5 scored highest among each tested models.

On frontier physics research, 1 spouse reported Fable 5 reached astir the aforesaid effect arsenic GPT-5.5 aft 36 hours, utilizing astir a 3rd of the reasoning tokens. GPT-5.5 required 4 days to scope a comparable result.

Vision and Long-Context Gains

Fable 5 completed the video crippled Pokémon FireRed utilizing lone earthy crippled screenshots, with nary maps, navigation aids, oregon further tools. Earlier Claude models required a much analyzable helper setup to play the aforesaid game.

On representation and long-context tasks, Anthropic said file-based representation improved Fable 5’s show connected the deck-building crippled Slay the Spire 3 times much than it improved Opus 4.8 nether the aforesaid conditions.

Mythos 5 and Cybersecurity

Anthropic besides launched Claude Mythos 5, built connected the aforesaid underlying exemplary arsenic Fable 5 with definite cybersecurity safeguards lifted. Mythos 5 is being deployed done Project Glasswing, a collaboration with the U.S. government, arsenic an upgrade to Claude Mythos Preview. Anthropic describes it arsenic carrying the strongest cybersecurity capabilities of immoderate AI exemplary presently available.

Safeguards and Availability

Fable 5 includes classifiers that redirect requests touching cybersecurity, biology and chemistry, oregon exemplary distillation to Claude Opus 4.8 alternatively than refusing outright. Anthropic says much than 95% of sessions trigger nary fallback astatine all.

A caller 30-day information retention argumentation applies to each Mythos-class exemplary traffic. Anthropic says the information volition not beryllium utilized for exemplary grooming and volition beryllium deleted aft 30 days successful astir each cases.

Fable 5 is disposable present connected Pro, Max, Team, and Enterprise plans astatine nary other outgo done June 22. On June 23, usage credits volition beryllium required. Anthropic said it intends to reconstruct Fable 5 arsenic portion of modular subscription plans erstwhile capableness allows.

Separately, Anthropic filed confidentially for an archetypal nationalist offering successful caller weeks. OpenAI followed with a akin filing soon after. Both developments arrived against a backdrop of continued selling pressure connected AI, semiconductor, and mega-cap tech stocks connected Wall Street.