Taylor is in India for Shop Quest, so Karl flies solo with Charles Swayne, owner and app developer at JadePuma Apps and the person behind Datify. Charles is 21, learned Python in sixth grade, and now runs a multi-agent development workflow that researches, plans, audits the plan, executes, and tests itself before he ever looks at the code.

We get into what that workflow actually looks like, which models he reaches for at each step and why, how he runs his own evals, and whether any of us should still be reading the PR. Plus Datify, structuring product data for agentic commerce, and what it was like when Mantle shut down.

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SPONSOR

Promo Party Pro is a free gift with purchase app Karl helped build with the team at Ethercycle. Set a spend threshold, show shoppers how close they are to earning a gift, and let the app handle the rest. Discount Functions under the hood, one app embed, no theme surgery, and campaigns auto-pause when the gift sells out.

Agencies: one of your clients gets a full year free. Not a trial, a year. https://promoparty.app/agency

Promo Party Pro - https://promoparty.app/ On the Shopify App Store - https://apps.shopify.com/promo-party-fgwp

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FIND CHARLES ONLINE

LinkedIn - https://www.linkedin.com/in/charles-swayne/ Datify on the Shopify App Store - https://apps.shopify.com/datify JadePuma Apps on the Shopify App Store - https://apps.shopify.com/partners/jadepuma-apps JadePuma - https://jadepuma.com/ BBQ on Ingraham, his neighborhood potluck - https://bbq-on-ingraham.onrender.com/

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TIMESTAMPS

Timestamps generated by AI show notes. These may shift slightly after final edit.

00:00 – Cold open: the boot disk that broke Dad's computer
00:35 – Taylor is in India, so Karl is on his own 
01:17 – Meeting at the water cooler, which was really the Diet Coke 02:50 – Python in sixth grade and a choose your own adventure ham sandwich 
03:37 – The internship with Scott Austin that turned into a career 
06:29 – The Rutgers full stack certificate, before Claude existed 
07:55 – How JadePuma Apps turns one client's problem into an app 08:47 – Admin extensions and printing jukebox strips from an order 09:45 – Tech stack, Heroku, Vercel, and the fear of picking the next Heroku 
11:48 – When Mantle shut down 
14:56 – Sponsor: Promo Party Pro 
16:10 – What Datify does, and the merchant with 700,000 products 19:05 – Seven apps, two Built for Shopify, and figuring out pricing 
20:59 – The agentic workflow: research, plan, audit, execute, test, review 22:00 – The plan reviewer skill, and why the plan matters more than the code 
24:25 – Subagent phases and picking a model for each one 
27:16 – Running your own evals: same prompt, two models, fifty times 28:30 – Screenshots, phone notifications, and automated test reports 29:57 – Hallucinations, scheming, and the Haiku that switched to Russian 
33:41 – Do you read the PR? Every AI feature ships with a security bug
36:23 – When the review loop never ends and you wonder if you should have done it yourself 
41:08 – Missing the grunt work, and grieving it together 
43:09 – From DOS 5 to agents, what we gained and what we lost 
44:44 – The SimCity theory of programming with agents 
47:00 – Dev Changelog 
49:15 – Picks of the Week

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DEV CHANGELOG

Polaris 2.0 release candidate https://shopify.dev/changelog/posts/polaris-2-0-release-candidate

Move existing subscriptions to Shopify App Pricing. Migration tooling in the partner dashboard, so there's not much excuse left. https://shopify.dev/changelog/posts/move-existing-subscriptions-to-shopify-app-pricing

Sidekick can now invoke app intents without tools. Surface app extensions and declare intents with no tools file. https://shopify.dev/changelog/posts/sidekick-can-now-invoke-app-intents-without-tools

2026-10 release notes. A very large batch, some of it action required. Scan it. https://shopify.dev/changelog/release-notes/2026-10

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ALSO MENTIONED

The Odin Project - https://www.theodinproject.com/ Omarchy - https://omarchy.org/ Microsoft PowerToys - https://learn.microsoft.com/windows/powertoys/

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PICKS OF THE WEEK

Karl: When Life Gives You Pears by Jeannie Gaffigan - https://www.amazon.com/dp/1538751046 – Her account of having a brain tumor removed, her family, and her faith. Not Karl's usual read, and it stuck with him.

Charles: Keyviz - https://keyviz.org/ – A widget that shows your last ten keystrokes, so when you fat-finger a shortcut you can see what you just did and undo it.