GPT-5.6: The Review
Theo spends 36 minutes putting real numbers behind the GPT-5.6 hype — Sol, Terra, and Luna, benchmarked against Claude Fable, one blog chart at a time.
July 12thTheo spends a day stress-testing Moonshot's 2.8-trillion-parameter open-weight release — and comes away convinced it's frontier-class, cheap enough to matter, and genuinely dangerous once the weights go public on July 27.
Kimi K3, a 2.8-trillion-parameter open-weight model from Moonshot, has closed the gap with the best closed frontier models on coding, UI generation, and 3D work at roughly Sonnet-level pricing — but it ships with real usability rough edges and no built-in refusal behavior once its weights go public.
Kimi K3 is Moonshot's new 2.8-trillion-parameter open-weight model, and after a full day of stress-testing, Theo finds it genuinely frontier-competitive — winning or tying frontier labs on coding, browser-agent, and front-end benchmarks, while pricing in at roughly Sonnet levels ($3 in / $15 out per million tokens). It handled a 3+ hour codebase port, generated a working 3D game and GBA emulator, redesigned a marketing site, and ran a 32-agent security audit that closed models often refuse. The catch: Moonshot's own release notes admit it's excessively proactive and has UX rough edges, it uses roughly twice the tokens of GPT-5.6 Sol to do the same work, and because it ships as open weights on July 27 with no built-in refusal behavior, its offensive security capability is now available to anyone.
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Theo states his thesis up front: open-weight models had stalled behind Fable/GPT-5.6 Sol, but Kimi K3's benchmarks suggest that gap just closed. He previews the video (usage tips, security implications) and mentions his terminal froze from overuse.

Mid-roll read for Depot — a CI engine and Docker build cache that speeds up GitHub Actions and Docker builds, usable from coding agents via CLI.

Theo reads Moonshot's own announcement: Kimi K3 is a 2.8T-parameter model with native vision and a 1M-token context window. He does the math on model size (2.8TB at FP8, 1.4TB at FP4) and bluntly debunks any claim that this could run as a 'local model.'

Walks through DeepSWE, FrontierSWE, terminal bench, Program Bench, SWE Marathon, and general agent evals (GDPval, Jobbench, Spreadsheetbench). Kimi K3 lands close behind or ahead of GPT-5.6 Sol and Fable across most. BrowseComp stands out: Kimi K3 beats the field on both score and cost per task.

Kimi K3 is live today via kimi.com, Kimi Work, Kimi Code, and the Kimi API — all Chinese-hosted, since the weights themselves don't release until July 27. Pricing: $0.30 cache hit, $3/mil in, $15/mil out — close to standard Sonnet pricing.

Covers the two architectural bets behind K3 — Kimi Delta Attention and Attention Residuals — plus a sparse Mixture-of-Experts setup (16 of 896 experts active) that keeps a model this large computationally viable, yielding a claimed 2.5x gain in scaling efficiency.

Theo's real-world stress test: porting his old ping.gg codebase, a job that ran 3+ hours and 122 tasks off a single prompt before hitting a context-window ceiling (caused by a subscription limit, not the model itself). He also flags Kimi K3's 76% win rate on the Frontend Code Arena leaderboard.

Kimi K3 builds a playable 3D Game Boy Advance emulator and, live on stream, ports Theo's 'Fish Slop' project into a working 3D submarine game complete with textures and sound effects — a capability Theo says every other model he's tried has badly fumbled.

Briefer callouts: Moonshot claims strong chip-design and ASIC research assistance, leading knowledge-work benchmarks (GDPval, DeckBench, FinanceBench) with polished infographic/dashboard generation, and even automated video-editing capability Theo hasn't tested himself.

Independent validation from Artificial Analysis: Kimi K3 ranks as the third-smartest model measured (intelligence index 57), just behind Fable and GPT-5.6 Sol, with a standout GDPval jump over the prior open-weight leader GLM 5.2.

The $15/mil output price isn't actually cheap once you factor in that Kimi K3 burns roughly 2x the tokens of GPT-5.6 Sol on the same task. Moonshot's own docs admit a UX gap versus Fable/Sol, call out excessive proactivity, and flag sensitivity to thinking-history continuity across sessions.

Theo has Kimi K3 generate five marketing-page redesigns for t3.gg (pill nav, glow/bento styles, an accidental 'cringe terminal' theme), then a genuinely-improved true-black sidebar redesign for his own product. A community example recreates macOS 27's Liquid Glass UI from scratch as a working web app.

Using OpenCode as the harness (Kimi isn't natively in Claude Code or Codex), Kimi K3 self-corrects a browser-access mistake, ships a real before/after PR, then Theo escalates to a much bigger test: a deep security audit of his production app, Lakebed.

Kimi K3 runs roughly 32 agents across discovery, verification, and synthesis phases to audit Lakebed for real vulnerabilities — a task Theo says Fable and Sol often refuse outright. He also notices it spontaneously restructures a to-do list into parallel workflows and lets sub-agents check off their own tasks, something he's never seen another model do.

Practical breakdown of kimi.com subscription tiers ($20/$40/$100/$200) versus the platform.kimi.ai API, plus Theo's own cost tally (~$63 for a full day of hard testing). Closes with a prediction that this release should worry Anthropic's upcoming Opus pricing.
A 2.8-trillion-parameter open-weight model now matches frontier coding and UI performance at roughly Sonnet-level pricing, which is genuinely useful for builders and genuinely alarming for AI safety once the weights ship publicly.
“Anyone who's telling you that this is the future of local models has no idea what they're talking about and they should be ignored forever.”
“This model requires supercomputers to be used.”
“Man, Anthropic has to be terrified of this release more than anybody.”
“I think we finally have a model that's good at solving real world UI tasks without having to pay Anthropic massive amounts of money.”
“All of that effort that Anthropic and OpenAI have been putting in to use their models for defense work and blocking them from doing offensive work is very helpful because that is no longer going to be enough to protect us now that we have an open weight model this capable.”
“I'm doing like a thousand dollars a day with OpenAI models right now just on weird side projects, and I do at least 3 to $400 a day with Fable for my day to day work.”
See every word as it's spoken — crank it to 2× and still catch all of it. The same dual-channel trick behind Amazon's Kindle + Audible.
Theo opens by admitting he'd stopped caring about open-weight models — none had come close to Fable or GPT-5.6 Sol on real coding work. Kimi K3, he says, might change that: benchmarks put it neck-and-neck with the frontier, so he spent a full day building with it to find out if the numbers hold up.
Four ways to use Kimi K3 before its weights release; Theo says ignore Kimi Work and Kimi Code and just use the kimi.com subscription or the raw API.
Theo blew through the $40 tier in about 30 minutes of aggressive testing and upgraded to $200, after which he stayed under 50% of his 5-hour cap and 10% of his weekly cap.
“check them out at soydev.link/depot”
Mid-roll sponsor read for Depot, framed as a natural break while Theo fixes his frozen terminal — low-friction, in-voice, doesn't disrupt the review's momentum.
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41:19Theo spends 36 minutes putting real numbers behind the GPT-5.6 hype — Sol, Terra, and Luna, benchmarked against Claude Fable, one blog chart at a time.
July 12thA day spent hammering Grok 4.5 inside Cursor turns a skeptical hook into a genuine benchmark scare for the rest of the frontier field.
July 9thA 28-minute benchmark teardown of Claude Sonnet 5, plus the government letter that brought Fable back from the dead.
July 1stTheo runs OpenAI's GPT-5.6-Sol through Claude Code instead of Codex and gets visibly better designs and cheaper orchestration — then reads Codex's system prompt on camera to find out why.
July 16thA same-day breakdown of why GPT-5.6 Codex drains rate limits so much faster than 5.5 — and the five habits that actually fix it.
July 13thOpenAI folded its beloved Codex app into a rebranded ChatGPT overnight -- Theo argues they just killed the best brand in AI coding.
July 11th