●MODEL — Claude Fable 5.1 and Claude Mythos 5.1 landed on September 1. They are the same underlying model; only the strength of the safeguards differs●PRICING — Per-token rates hold at $10/$50 per MTok. What changed is cache reads, cut 75% to $0.25 per MTok●COST — How much that saves depends on your workload: roughly 25% for typical use, up to about 45% for context-heavy agentic work. Worth measuring your own split before quoting a number●BENCH — Terminal-Bench-Science 0.1 climbs from 24.7% on Fable 5 to 52.6%. Anthropic also states a standard error of 3.5-4.5 points, which is worth remembering before reading small gaps as real●SAFEGUARDS — Sharper cyber safeguards cut interventions in Claude Code sessions by roughly 60% on average. Finding vulnerabilities is now allowed; developing exploits still is not●API — New API accounts created from today can no longer edit prior context while preserving Claude's thinking transcript. It is an anti-distillation measure, and existing accounts are unaffected for now●MODEL — Claude Fable 5.1 and Claude Mythos 5.1 landed on September 1. They are the same underlying model; only the strength of the safeguards differs●PRICING — Per-token rates hold at $10/$50 per MTok. What changed is cache reads, cut 75% to $0.25 per MTok●COST — How much that saves depends on your workload: roughly 25% for typical use, up to about 45% for context-heavy agentic work. Worth measuring your own split before quoting a number●BENCH — Terminal-Bench-Science 0.1 climbs from 24.7% on Fable 5 to 52.6%. Anthropic also states a standard error of 3.5-4.5 points, which is worth remembering before reading small gaps as real●SAFEGUARDS — Sharper cyber safeguards cut interventions in Claude Code sessions by roughly 60% on average. Finding vulnerabilities is now allowed; developing exploits still is not●API — New API accounts created from today can no longer edit prior context while preserving Claude's thinking transcript. It is an anti-distillation measure, and existing accounts are unaffected for now