Flux
A pelican for GPT-5.5 via the semi-official Codex backdoor API

A pelican for GPT-5.5 via the semi-official Codex backdoor API

GPT-5.5 is out. It's available in OpenAI Codex and is rolling out to paid ChatGPT subscribers. I've had some preview access and found it to be a fast, effective and highly capable model. As is usually the case these days, it's hard to put into words what's good about it - I ask it to build things and it builds exactly what I ask for! There's one notable omission from today's release - the API: API deployments require different safeguards and we are working closely with partners and customers on…

Simon Willison's Weblog
Quoting Maggie Appleton

Quoting Maggie Appleton

[...] if you ever needed another reason to learn in public by digital gardening or podcasting or streaming or whathaveyou, add on that people will assume you’re more competent than you are. This will get you invites to very cool exclusive events filled with high-achieving, interesting people, even though you have no right to be there. A+ side benefit. — Maggie Appleton, Gathering Structures (via) Tags: blogging, maggie-appleton

Simon Willison's Weblog
Behavioral Credentials: Why Static Authorization Fails Autonomous Agents

Behavioral Credentials: Why Static Authorization Fails Autonomous Agents

Enterprise AI governance still authorizes agents as if they were stable software artifacts.They are not. An enterprise deploys a LangChain-based research agent to analyze market trends and draft internal briefs. During preproduction review, the system behaves within acceptable bounds: It routes queries to approved data sources, expresses uncertainty appropriately in ambiguous cases, and maintains source […]

O'Reilly Radar — AI/ML
Qwen3.6-27B: Flagship-Level Coding in a 27B Dense Model

Qwen3.6-27B: Flagship-Level Coding in a 27B Dense Model

Qwen3.6-27B: Flagship-Level Coding in a 27B Dense Model Big claims from Qwen about their latest open weight model: Qwen3.6-27B delivers flagship-level agentic coding performance, surpassing the previous-generation open-source flagship Qwen3.5-397B-A17B (397B total / 17B active MoE) across all major coding benchmarks. On Hugging Face Qwen3.5-397B-A17B is 807GB, this new Qwen3.6-27B is 55.6GB. I tried it out with the 16.8GB Unsloth Qwen3.6-27B-GGUF:Q4_K_M quantized version and llama-server using…

Simon Willison's Weblog
Don’t Blame the Model

Don’t Blame the Model

The following article originally appeared on the Asimov’s Addendum Substack and is being republished here with the author’s permission. Are LLMs reliable? LLMs have built up a reputation for being unreliable. Small changes in the input can lead to massive changes in the output. The same prompt run twice can give different or contradictory answers. […]

O'Reilly Radar — AI/ML
Quoting Bobby Holley

Quoting Bobby Holley

As part of our continued collaboration with Anthropic, we had the opportunity to apply an early version of Claude Mythos Preview to Firefox. This week’s release of Firefox 150 includes fixes for 271 vulnerabilities identified during this initial evaluation. [...] Our experience is a hopeful one for teams who shake off the vertigo and get to work. You may need to reprioritize everything else to bring relentless and single-minded focus to the task, but there is light at the end of the tunnel. We…

Simon Willison's Weblog
Changes to GitHub Copilot Individual plans

Changes to GitHub Copilot Individual plans

Changes to GitHub Copilot Individual plans On the same day as Claude Code's temporary will-they-won't-they $100/month kerfuffle (for the moment, they won't), here's the latest on GitHub Copilot pricing. Unlike Anthropic, GitHub put up an official announcement about their changes, which include tightening usage limits, pausing signups for individual plans (!), restricting Claude Opus 4.7 to the more expensive $39/month "Pro+" plan, and dropping the previous Opus models entirely. The key…

Simon Willison's Weblog
Is Claude Code going to cost $100/month? Probably not - it's all very confusing

Is Claude Code going to cost $100/month? Probably not - it's all very confusing

Anthropic today quietly (as in silently, no announcement anywhere at all) updated their claude.com/pricing page (but not their Choosing a Claude plan page, which shows up first for me on Google) to add this tiny but significant detail (arrow is mine, and it's already reverted): The Internet Archive copy from yesterday shows a checkbox there. Claude Code used to be a feature of the $20/month Pro plan, but according to the new pricing page it is now exclusive to the $100/month or $200/month Max…

Simon Willison's Weblog