Lenny's Newsletter·2d ago
Claude Fable 5 review: what the new Mythos model gets right (and very wrong)Claude Fable 5 (Mythos-class) delivers impressive benchmarks and handles complex tasks well, but plays it too conservatively on execution and burns tokens aggressively by design.
- Fable 5 excels at planning and specification work (product graphs, architecture design) but hesitates to commit to concrete implementation decisions.
- The model is token-intensive by design, meaning higher costs for equivalent work compared to previous generations.
- New safety classifiers with fallback concepts give Anthropic more control over outputs, raising questions about whether this is truly a leap forward or a refined version.
- Real-world testing on multi-agent orchestration and skills registry design revealed the model's caution limits its utility for execution-heavy workflows.
The insight — Fable 5's conservatism—while safer—makes it better at thinking through problems than actually solving them, which may force users to build more scaffolding or validation layers around it.
Read the full post →Lenny's Newsletter·3d ago
Essential books for product builders—part 2A curated collection of timeless books organized by professional and personal growth goals, with the philosophy that retaining one golden nugget per book compounds into lasting value.
- Read 10 minutes before bed as a wind-down routine that improves both retention and sleep quality.
- Extract one actionable tactic per book, photograph it, and email it to yourself for implementation that week rather than aiming for complete retention.
- Design and taste are learnable skills, not innate—objectively improve UX through books like Don't Make Me Think and Refactoring UI.
- Influence matters more than talent for career advancement; master it through understanding social proof, authority, scarcity, and likability rather than negotiation tactics alone.
- The fastest career risers focus deeply on fewer things rather than spreading effort thin across many priorities.
The insight — Books function as compressed life experiences—accessing someone else's decades of learning in hours—but the real multiplier is extracting one specific, implementable insight per book rather than seeking complete mastery of each.
Read the full post →Stratechery by Ben Thompson·3d ago
The iPhone’s Last StandApple's Siri AI strategy leverages the iPhone's unique access to personal data to dominate consumer AI, while Microsoft's cloud-based agent approach makes more sense for enterprise—but only Apple can realistically build the consumer context needed for truly useful AI.
- Microsoft's Project Solara envisions thin-client devices as mere portals to cloud-based AI agents that do work without user interaction, but this model fits enterprise better than consumers who don't actually want productivity tools.
- Apple's advantage is that the iPhone already knows more about you than any other device, allowing Siri to solve specific, personalized problems across your apps and messages with low reputation risk.
- Consumers don't want agents buying concert tickets; they want to watch short-form video—making 'good enough' Siri sufficient, while productivity-focused agents will primarily succeed in enterprise where employers pay for worker time.
- Apple's iPhone-centric approach isn't just business incentive alignment; it's strategically sound because only Apple (and maybe Google) can aggregate the personal data context needed to build truly useful consumer AI.
- The real test is whether Apple's Siri remains a working product rather than vaporware, but the company's technical choices—on-device mixture-of-experts models and Private Cloud Compute—suggest this time it will ship.
The insight — The future of AI splits by market: enterprises will adopt server-side agents to handle complex work, while consumers will use device-native AI anchored to personal context—meaning the winner for consumers is whoever controls the device with the most intimate knowledge of your life, which is Apple.
Read the full post →