We Tried Jev To See If It's Any Good - This Week In AI

This week, X could not stop talking about Jev, a viral new "decision model" that hit 38 million views on launch. Shane and Abhi break down what it actually is, and Abhi builds with it live in seven demos. Jev is not an LLM. Instead of returning text, it returns structured output with a calibrated probability, trained with a new method its creators call RLCD (reinforcement learning for calibrated decisions). The pitch is 20 to 200x faster and 40 to 400x cheaper than an LLM, with output tokens free, and the community went wild: people cloned it, built programming languages and generative UI on top of it, and half of X argued over whether it is really just an if-statement.

Abhi spent the weekend adding Jev to every primitive in Mastra as a new classifier and assessed where it helps and where it does not. He wires classifiers into workflow branching, turns PII and abuse detection into cheap guardrail processors, tries tool-search pre-selection, tests model routing (he is not convinced), and shows tool approvals and classifier-as-judge scoring. The honest takeaway: it is a genuinely useful new tool for the belt, not the revolution the hype claims, and the marketing was better than the breakthrough.

Before all that, Shane opens on Gergely Orosz's deep dive into OpenAI's software factory and how Codex took over there, and why the reaction from a lot of people was "that's it?" Plus the first SF Software Factory meetup on October 14th.

Quick hits: Claude Code finally reads AGENTS.md, an open-weight 7B (Qwen-Image-2.1) beats Nano Banana 2.0, shadcn/lint gives agents a design-system linter, an offline OS hallucinated with Qwen 3.8, Factory raised $200M at a $5B valuation, and Tobi coins "slop grenades."

AI Agents Hour is a weekly livestream by Mastra CPO Shane Thomas and CTO Abhi Aiyer. Mondays 12PM Pacific.

📚 READ MORE
OpenAI's software factory (Pragmatic Engineer): https://newsletter.pragmaticengineer.com/p/openai-software-factory
Gemini joins the felony bench: https://x.com/Sauers_/status/2101090412454715840
The Jev launch: https://x.com/completeskeptic/status/2099925682726002904
The pitch, 200x faster, 400x cheaper: https://x.com/k_grajeda/status/2099952715430596710
Day 3, "what if Jev was an if-statement?": https://x.com/southpolesteve/status/2100767781868150938
The clones, Kev-0.5B on a MacBook: https://x.com/jaredpalmer/status/2101028325472841920
Claude Code now reads AGENTS.md: https://x.com/trq212/status/2101009392611278961
Open-weight 7B beats Nano Banana 2.0: https://x.com/kimmonismus/status/2101679965590769872
shadcn/lint: https://x.com/shadcn/status/2099534231114314145
Factory raises $200M at $5B: https://x.com/FactoryAI/status/2099907042123403466
Tobi's "slop grenades": https://x.com/shaneparrish/status/2099852161576223202

📚 MASTRA RESOURCES
Mastra: https://mastra.ai
Mastra on X: https://x.com/mastra_ai
Mastra Discord: https://mastra.ai/community/discord
Mastra GitHub: https://github.com/mastra-ai
Learn Mastra: https://mastra.ai/learn
Principles of Building AI Agents (Book): https://mastra.ai/books/principles-of-building-ai-agents
Patterns for Building AI Agents (New Book): https://mastra.ai/books/patterns-of-building-ai-agents

WHAT IS MASTRA?
Mastra is an open-source TypeScript framework designed for building and shipping AI-powered applications and agents with minimal friction. It supports the full lifecycle of agent development—from prototype to production. You can integrate it with frontend and backend stacks (e.g., React, Next.js, Node) or run agents as standalone services. If you're a JavaScript or TypeScript developer looking to build an agentic or AI-powered product without starting from first principles, Mastra provides the scaffolding, tools, and integrations to accelerate that process.

⏱️ CHAPTERS
00:00 Cold open: what is Jev?
00:32 Welcome + SF Software Factory meetup
01:24 The OpenAI software factory article
04:07 Gemini joins the felony bench
04:40 The Jev saga: a viral decision model
07:58 What Jev actually is (classifier, RLCD)
10:23 Demo: shipping a classifier primitive in Mastra
15:05 Classifiers in workflows (branching)
17:02 Guardrails
19:22 Tool search pre-selection
20:56 Model routing
22:48 Tool approvals & classifier-as-judge
26:50 Jev: The verdict
27:22 Claude Code reads AGENTS.md
28:17 Qwen-Image-2.1 beats Nano Banana 2.0
28:30 shadcn/lint
28:44 An offline OS hallucinated by Qwen 3.8
29:13 Factory raises $200M at $5B
29:29 "Slop grenades"
29:58 Mastra Radio