J
EP. 010
AI for Solo Founders
WEDNESDAY, SEPTEMBER 23, 2026
Two new models dropped this week, so I made them fight.
Anthropic released Opus 5.5 yesterday. OpenAI shipped GPT-6 Sol and Luna the same day.
I gave Opus 5.5 and GPT-6 Astra the exact same prompt and had each one build me a Pomodoro timer, both a web app and a Mac app. You'll see how it went and get the prompt.
Meta's new assistant turned my Instagram saves graveyard into a content dashboard.
Plus a heads up on Dojo pricing before October 1.
Here's the week.
THIS WEEK IN AI
1
Why it matters: Anthropic says it performs at the level of Fable 5.1, their top model, on most work. It's also over 30% faster than Opus 5 and about 40% cheaper to run.
For you that means higher usage limits on Pro and Max, and tighter writing. Anthropic says it puts the most important information up front. Sonnet 5.5 and Haiku 5.5 are coming within weeks.
ANTHROPIC · 5 MIN READ
2
Why it matters: Same day as Opus 5.5. Coincidence, I'm sure.
Sol is the everyday workhorse, and OpenAI says it makes about half as many mistakes as the last version. Luna is the cheap, fast one for grunt work: summarizing docs, pulling out info, quick questions. Both are live in ChatGPT Work and Codex on Plus and up. Free users get Luna on the desktop app.
TECHCRUNCH · 4 MIN READ
THE HEAD TO HEAD
Opus 5.5 vs GPT-6 Astra: one prompt, one app
I didn't want another app with half its features behind a paywall, so I had the two best models build me one.
I'm adding live 90 minute coworking sessions inside the Dojo (more on that below), and I needed a timer to run them on.
One prompt, the same for both. Research the best Pomodoro apps on the Mac App Store, study the features and the design, then build me something slick with light and dark mode that runs in the browser, plus a Mac app.
I didn't give either of them a feature list. They had to go find it.
Here's the crazy part. They came back with almost the exact same app, feature for feature.
The difference was design, and Opus 5.5 won that for me. Astra went clean and quiet with blue accents. Opus built a dial that lights up tick by tick and tints the whole screen by mode: tomato for focus, teal for breaks.
Call it a draw on function and Opus on looks. Either one beats paying $40 a year for a timer.
Both are live. Tap either screenshot below to open it and use it yourself.
Opus 5.5. Tap to open.
GPT-6 Astra. Tap to open.
PROMPT OF THE WEEK
The one prompt that built both apps
Swap "Pomodoro timer" for whatever app you're paying for and shouldn't be. Works in Claude Code or Codex.
I want you to research all of the best Pomodoro timer apps.
Look at the best-performing apps on the Mac App Store. Research their features and study their design.
Then design and build me something super slick that has light and dark modes and that I can run directly in the browser. Put that version live on a site I can open from anywhere.
See the full promptShow less
I want you to research all of the best Pomodoro timer apps.
Look at the best-performing apps on the Mac App Store. Research their features and study their design.
Then design and build me something super slick that has light and dark modes and that I can run directly in the browser. Put that version live on a site I can open from anywhere.
I also want you to build me a macOS app.
COPY · PASTE · REPLACE THE BRACKETS
TOOL OF THE WEEK
Muse (by Meta)
Free with weekly limits. Paid plans at $20 and $100/mo.
I didn't think I was going to like it. The truth is I really do.
Muse is Meta's new personal AI assistant. It isn't trying to be some overloaded AI app that does everything. It's just your assistant, and it's really good.
I pointed it at the Content Ideas folder in my Instagram saves, and it turned everything in there into a full content dashboard I can check anytime.
153 saved posts in. Seven ready to shoot reels and three finished carousels out, ranked by what to shoot this week.
Ready to shoot reels with the script, the on-screen text, and B-roll ideas. The full caption. What goes in my ManyChat DM automation. Carousels, already written.
And because Meta owns Instagram, there's no third-party integration to set up. It already knows how I talk from analyzing my own content.
You can also connect your other apps, get a morning brief, and chat with it right inside WhatsApp.
Verdict: Try it. It's free, and if Instagram is your source of truth, no other tool gets this kind of access.
Try it →
The dashboard. Watch the reel.
Seven reels, scripted. Watch the reel.
道
The Dojo goes to $79 on October 1
It's $59 a month right now. On October 1 it goes to $79 for the next 50 members, then $99 once we hit 150.
Already inside? Your price doesn't change.
New this month: live 90 minute coworking sessions. Cameras on, timer running, the most productive 90 minutes of your week. Dojo members only.
Join the Dojo
100+ FOUNDERS INSIDE
by Justyn. Shipped with 
by AI.