The Frontier edition

The Frontier · 24 Sep 2026

24 Sep 2026 · 15 articles

Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and a new price war

Yesterday was Grok 4.7 ( pelicans ) and MiMo v2.6 Flash/Pro ( more pelicans ). Today Anthropic released Claude Opus 5.5 , and around an hour later OpenAI released GPT-6 Sol and GPT-6 Luna . It's going to take a while to get a good read on all of these new models, but here are my impressions so far. GPT-6 Sol and Luna are half the price of their GPT-5.6 equivalents GPT-5.6 Luna was already my…

Summary published by Simon Willison's Weblog · 22 Sep 2026 · Read the original ↗

Claude Opus 5.5: The System Card

Introducing the world’s most powerful model, at least by some measures like Artificial Analysis or any standard benchmark list, which is now Claude Opus 5.5.

Summary published by Don't Worry About the Vase · 23 Sep 2026 · Read the original ↗

Gemini 3.8 TTS Playground

Tool: Gemini 3.8 TTS Playground Google released two new Gemini text-to-speech models today - gemini-3.8-flash-tts and gemini-3.8-flash-lite-tts . They come with a library of over 2,000 voices, plus the ability to create a custom voice with "just a 30-second audio sample of your voice or a voice you have the rights to use". I vibe coded this bring-your-own-key playground interface with GPT-6…

Summary published by Simon Willison's Weblog · 23 Sep 2026 · Read the original ↗

Stripe's Knowledge AI Platform

Article URL: https://stripe.dev/blog/meet-stripes-knowledge-ai-platform Comments URL: https://news.ycombinator.com/item?id=49815982 Points: 176 # Comments: 110

Summary published by Hacker News - Newest: "AI" · 23 Sep 2026 · Read the original ↗

SF October 14th: A Birds of a Feather Session on Agentic Engineering

I'm hosting an evening event with Jesse Vincent in San Francisco on Wednesday 14th October for people who are building weird and interesting things with and on top of coding agents. Think of it as an agentic show-and-tell: ​Compare notes with other builders and experimenters on things you’re trying, what you're learning, and what you haven’t figured out yet. We’re especially interested in…

Summary published by Simon Willison's Weblog · 23 Sep 2026 · Read the original ↗

How to train your own Jev for $17

We just launched our own Jev-like classifier, together/Tev1-4B-experimental, on top of Qwen3.5 4B on Together’s serverless platform. In this blog post we’ll show you how to fine-tune your own version!

Summary published by Together.ai · 23 Sep 2026 · Read the original ↗

llm 0.36

Release: llm 0.36 New OpenAI models: gpt-6-sol for GPT-6 Sol and gpt-6-luna for GPT-6 Luna . #1702 Model plugins can now declare supports_conversation = False for models that only accept single-turn prompts. LLM raises llm.ConversationNotSupported when these models receive assistant or tool history, and llm chat rejects them before starting a session. See Models that do not support conversations…

Summary published by Simon Willison's Weblog · 22 Sep 2026 · Read the original ↗

llm-anthropic 0.29

Release: llm-anthropic 0.29 Adds support for Claude Opus 5.5 : llm -m claude-opus-5.5 "prompt goes here" Tags: llm , anthropic

Summary published by Simon Willison's Weblog · 22 Sep 2026 · Read the original ↗

Jev introduces a new shape of LLM - System One, aka Decision Models

Last week TypeSafe AI unveiled Jev , their first example of a new category of model that they are calling "System One models" (I'm with Maggie Appleton, I think "decision models" is a better name for these). Jev is an interesting variant on the usual LLM format: it still accepts text inputs, but instead of text output it returns floating point numbers corresponding to categories, yes/no…

Summary published by Simon Willison's Weblog · 21 Sep 2026 · Read the original ↗

Frontier AI on Your Own Hardware

Article URL: https://timdettmers.com/2026/09/21/dlab-open-source-week/ Comments URL: https://news.ycombinator.com/item?id=49791647 Points: 183 # Comments: 103

Summary published by Hacker News - Newest: "AI" · 21 Sep 2026 · Read the original ↗

Can Jev Be a Better Agent Evaluator?

We tested using Jev-as-a-Judge against LLM judges on accuracy, repeatability, latency, and cost to see whether System One models could offer a new approach to agent evaluation.

Summary published by LangChain Blog · 20 Sep 2026 · Read the original ↗