AI tool comparison
OpenMythos vs Yahoo Scout
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Research & Open Source
OpenMythos
Open-source PyTorch reconstruction of Claude Mythos' suspected architecture
75%
Panel ship
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Community
Paid
Entry
OpenMythos is a PyTorch reconstruction of the suspected architecture underlying Anthropic's Claude Mythos model, built entirely from published research. Creator Kye Gomez hypothesizes that Mythos uses a Recurrent-Depth Transformer (RDT) — where a subset of transformer layers loops multiple times per forward pass with shared weights rather than stacking unique layers. This allows the model to simulate "thinking" by iterating over the same compute graph, giving it emergent chain-of-thought behavior without explicit CoT prompting. At 770M parameters, the OpenMythos implementation reportedly matches the downstream quality of a 1.3B standard transformer on benchmarks. The architecture combines Multi-Latent Attention for memory compression, LTI (Linear Time-Invariant) stability constraints to prevent training instability during recurrence, Mixture of Experts routing for specialization, and Adaptive Computation Time (ACT) halting to decide when to stop looping per token. The project exploded on GitHub within days — 6.2k stars, 1.2k forks — and Kye's X announcement drove massive engagement (4.1k likes, 4.5k reposts). Community reaction is genuinely divided: AI researchers calling it "the most sophisticated reverse-engineering of an LLM architecture I've seen" while Anthropic has not confirmed or denied any of the architectural claims. This is an educated speculation backed by real engineering, not a marketing exercise.
AI Search
Yahoo Scout
Yahoo's Claude-powered AI answer engine — with citations, built for 250M users
50%
Panel ship
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Community
Free
Entry
Yahoo Scout is Yahoo's full-scale return to search, powered by Anthropic's Claude and grounded in both Yahoo's proprietary data and Microsoft Bing. Available at scout.yahoo.com and embedded across Yahoo News, Finance, Mail, and Search for ~250 million U.S. users. Every response includes inline citations designed to send traffic back to publishers — a deliberate move to rebuild the 'social contract' between search and journalism that Google AI Overviews fractured. Scout launched in January 2026 and has been rapidly expanding. It's notably different from ChatGPT Search in emphasizing source attribution over answer completeness.
Reviewer scorecard
“Whether or not Anthropic actually uses this architecture, the RDT implementation itself is genuinely impressive engineering. The ACT halting mechanism and LTI stability constraints are clever solutions to problems anyone trying to build reasoning models will face. Fork-worthy regardless of the Mythos speculation.”
“Yahoo Scout is a solid product but its distribution advantage — 250M users — is its only real differentiator over Perplexity or You.com. The Claude integration is good but doesn't do anything developers can't get from claude.ai directly. It's a consumer product, not a developer tool.”
“This is reverse engineering based on vibes and published papers, not leaked weights or verified architecture docs. Anthropic hasn't confirmed a thing. The 770M benchmark comparisons are cherrypicked and the '1.3B equivalent quality' claim needs independent reproduction. Intellectually interesting, empirically unverified.”
“Yahoo has tried multiple search relaunches over the past decade and none stuck. The Claude foundation is good but the search market is brutal — Perplexity has a head start, Google has scale, ChatGPT has stickiness. Citation-first positioning is a nice differentiator, but it's a values argument in a market that selects on answer quality.”
“Regardless of whether Mythos actually is an RDT, this project demonstrates that open-source researchers can meaningfully reconstruct competitive reasoning architectures from scratch. That capability gap between frontier labs and open-source is closing faster than most realize.”
“Publisher-first citations are the sustainable design principle for AI search that Google fumbled. Yahoo's scale means this choice actually moves dollars back to journalism at meaningful volume. Whether Scout succeeds or not, forcing that design convention into a mass-market product matters for the media ecosystem.”
“A 6.2k star project in two days means something hit a nerve. The documentation is excellent — clear architecture diagrams, detailed training notes, working code. Even if the Mythos speculation is wrong, this is a model for how to share research engineering properly.”
“The fact that Yahoo Scout sends traffic back to publishers is the most creator-friendly thing in AI search right now. Every AI answer that links to sources instead of absorbing them is revenue that flows to writers. It's not altruistic — it's embedded across Yahoo Finance and News — but the incentives are aligned in the right direction.”
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