<p><strong>Tool:</strong> <a href="https://tools.simonwillison.net/kakapo-party">Kākāpō Party</a></p> <p>I presented a closing keynote for the <a href="https://www.wearedevelopers.com/world-congress-north-america">WeAreDevelopers World Congress North America</a> yesterday. As <a href="https://simonwillison.net/2019/Dec/10/better-presentations/">a STAR moment</a> I decided to weave in references to the record breaking <a href="https://www.doc.govt.nz/news/media-releases/2026-media-releases/kakapo-population-reaches-new-milestone/">kākāpō breeding season</a> we had in 2026.</p><p>For my closing slide I wanted to celebrate, and I had seen some buzz around how good Claude Opus 5.5 was at creating pixel art animations. So I rounded up three Kakapo photos from Google image search and dropped them into Claude with this prompt:</p><blockquote><p><code>Here are some photos of kakapo parrots just to remind you what they look like</code></p><p><code>I need you to make an animation in animated pi

<blockquote cite="https://daringfireball.net/linked/2026/09/25/aten-muse"><p>Muse is getting a lot of attention — including mine — because it’s both groundbreaking technically (each user gets their own entire persistent Linux VM running in Meta’s cloud) <em>and</em> because it’s packaged in an easy-to-install easy-to-use way. It’s literally presented as <a href="https://daringfireball.net/linked/2026/09/24/song-meta-muse-cute">a cute mascot</a>. It’s the first consumer-accessible agentic AI system, and Meta has truly done an amazing job with that. But it’s a genuinely open question whether consumers have any understanding what this means. If you buy a power saw that can cut your fingers off, you are almost certainly aware that you are buying a power saw that can sever your fingers. [...] I don’t think people realize how powerful — and thus dangerous — Muse is, especially if it’s running on your Mac.</p></blockquote><p class="cite">&mdash; <a href="https://daringfireball.net/linked/202

<p><img src="https://static.inaturalist.org/photos/740453177/large.jpg" alt="Northern Gannet"></p><p><img src="https://static.inaturalist.org/photos/740453341/large.jpg" alt="Great Blue Heron"></p><p><img src="https://static.inaturalist.org/photos/740454506/large.jpg" alt="California Brown Pelican"></p><p>Northern Gannet, Great Blue Heron, California Brown Pelican, in Monterey Bay National Marine Sanctuary, CA, US, CA</p><p>New 200-800mm Canon EF lens got me my best photo of <a href="https://simonwillison.net/2026/Aug/15/sighting-391300422/">Morris</a> yet. They really like hanging out under that sign in the harbor!</p> <p>Tags: <a href="https://simonwillison.net/tags/photography">photography</a>, <a href="https://simonwillison.net/tags/wildlife">wildlife</a></p>

<p>The more time I spend working with coding agents, the more convinced I am that they make software engineering even harder.</p><p>We can do amazing things with them, but unlocking their full potential requires extraordinary discipline and knowledge.</p> <p>Tags: <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a></p>

<p><strong>Release:</strong> <a href="https://github.com/simonw/commit-rewriter/releases/tag/0.2">commit-rewriter 0.2</a></p> <blockquote><p>Support for branches other than the default branch. Use <code>uvx commit-rewriter --branch other</code> to run against another branch. <a href="https://github.com/simonw/commit-rewriter/issues/3">#3</a></p></blockquote> <p>Tags: <a href="https://simonwillison.net/tags/git">git</a></p>

<p><strong>Release:</strong> <a href="https://github.com/simonw/datasette/releases/tag/1.0a41">datasette 1.0a41</a></p> <p>Alec Garcia added <a href="https://docs.datasette.io/en/latest/internals.html#internals-telemetry">support for OpenTelemetry</a> to Datasette in this release.</p><p>I've also refactored all of Datasette's modal dialogs to a single Web Component, which is now <a href="https://docs.datasette.io/en/latest/javascript_plugins.html#javascript-plugins-modals">documented for other plugins to use</a>.</p> <p>Tags: <a href="https://simonwillison.net/tags/javascript">javascript</a>, <a href="https://simonwillison.net/tags/datasette">datasette</a>, <a href="https://simonwillison.net/tags/web-components">web-components</a>, <a href="https://simonwillison.net/tags/alex-garcia">alex-garcia</a>, <a href="https://simonwillison.net/tags/opentelemetry">opentelemetry</a></p>

<p><strong>Tool:</strong> <a href="https://tools.simonwillison.net/gemini-tts-playground">Gemini 3.8 TTS Playground</a></p> <p>Google <a href="https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-8-text-to-speech/">released two new Gemini text-to-speech models</a> today - <code>gemini-3.8-flash-tts</code> and <code>gemini-3.8-flash-lite-tts</code>.</p><p>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".</p><p>I <a href="https://tools.simonwillison.net/markdown-svg-renderer?url=https%3A%2F%2Fgist.github.com%2Fsimonw%2Fa82f3aef2677c623d1776092d6b21224">vibe coded</a> this bring-your-own-key playground interface with GPT-6 Astra, taking advantage of the open CORS policy of the underlying Gemini API.</p><p><img alt="Screenshot of a web app for composing multi-speaker text-to-speech conversations, with a Compose panel on the left and C

<p><strong>Tool:</strong> <a href="https://tools.simonwillison.net/shadow-roots">Shadow roots, explained with live examples</a></p> <p>Prompt to Fable 5.1 Medium:</p><blockquote><p><code>Build an artifact to explain shadow roots in CSS with interactive examples</code></p></blockquote> <p>Tags: <a href="https://simonwillison.net/tags/css">css</a></p>

<p><strong><a href="https://luma.com/vxuiuyvg">SF October 14th: A Birds of a Feather Session on Agentic Engineering</a></strong></p>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.</p><p>Think of it as an agentic show-and-tell:</p><blockquote><p>​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 work you haven’t discussed publicly, odd experiments, or unfinished projects that don’t have an obvious market.</p><p>​Expect one flowing conversation with an informal show-and-tell. Sharing something you’re working on is encouraged but no presentation is required.</p></blockquote><p>This isn't about product pitches, it's about much earlier explorations than that. This agentic AI stuff is weird! Let's celebrate and lean into that weirdness. <p>Tag

<p>Yesterday was <a href="https://x.ai/news/grok-4-7">Grok 4.7</a> (<a href="https://news.ycombinator.com/item?id=49788838#49790209">pelicans</a>) and <a href="https://mimo.xiaomi.com/mimo-v2-6">MiMo v2.6 Flash/Pro</a> (<a href="https://news.ycombinator.com/item?id=49792730#49793480">more pelicans</a>). Today Anthropic <a href="https://www.anthropic.com/claude-opus-5-5">released Claude Opus 5.5</a>, and around an hour later OpenAI <a href="https://openai.com/index/introducing-gpt-6-sol-and-luna/">released GPT-6 Sol and GPT-6 Luna</a>. 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.</p><h4 id="gpt-6-sol-and-luna-are-half-the-price-of-their-gpt-5-6-equivalents">GPT-6 Sol and Luna are half the price of their GPT-5.6 equivalents</h4><p>GPT-5.6 Luna was already my favorite model for building applications against, because it combined excellent performance with being <em>really cheap</em>. Somehow GPT-6 Luna is half the price of t

<p><strong>Release:</strong> <a href="https://github.com/simonw/llm/releases/tag/0.36">llm 0.36</a></p> <blockquote><ul><li>New OpenAI models: <code>gpt-6-sol</code> for <a href="https://developers.openai.com/api/docs/models/gpt-6-sol">GPT-6 Sol</a> and <code>gpt-6-luna</code> for <a href="https://developers.openai.com/api/docs/models/gpt-6-luna">GPT-6 Luna</a>. <a href="https://github.com/simonw/llm/issues/1702">#1702</a></li><li>Model plugins can now declare <code>supports_conversation = False</code> for models that only accept single-turn prompts. LLM raises <code>llm.ConversationNotSupported</code> when these models receive assistant or tool history, and <code>llm chat</code> rejects them before starting a session. See <a href="https://llm.datasette.io/en/stable/plugins/advanced-model-plugins.html#advanced-model-plugins-conversations">Models that do not support conversations</a>. The first plugin to use this is <a href="https://github.com/simonw/llm-typesafe">llm-typesafe</a>. <a

<blockquote cite="https://www.tiktok.com/@therealcornpop/video/7687243097801051422"><p>Hey, you know it's like super obvious if you're using AI to write your scripts for TikTok and YouTube, right? [...] It's not just the general AI-isms of "it's not X, it's Y", or the rule of three, or the really weird broken staccato-like way of writing where you just say a lot of things with all these punctuation marks. and it sounds really deep, but it's not.</p><p>It's the lack of <em>anything</em>. It's the lack of a definitive sort of spear of your voice. It's the fact I can tell you don't have opinions about the thing that you're talking about.</p></blockquote><p class="cite">&mdash; <a href="https://www.tiktok.com/@therealcornpop/video/7687243097801051422">@therealcornpop</a>, on TikTok</p> <p>Tags: <a href="https://simonwillison.net/tags/tiktok">tiktok</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/ai-misuse">ai-misuse</a></p>

<p><strong>Release:</strong> <a href="https://github.com/simonw/llm-anthropic/releases/tag/0.29">llm-anthropic 0.29</a></p> <p>Adds support for <a href="https://www.anthropic.com/claude-opus-5-5">Claude Opus 5.5</a>:</p><pre><code>llm -m claude-opus-5.5 "prompt goes here"</code></pre> <p>Tags: <a href="https://simonwillison.net/tags/llm">llm</a>, <a href="https://simonwillison.net/tags/anthropic">anthropic</a></p>

<p><strong>Release:</strong> <a href="https://github.com/simonw/llm-typesafe/releases/tag/0.1a0">llm-typesafe 0.1a0</a></p> <p>I built this new plugin for <a href="https://llm.datasette.io/">LLM</a> to add support for <a href="https://simonwillison.net/2026/Sep/21/jev/">TypeSafe AI's new Jev model</a>. Install it like this:</p><pre><code>llm install llm-typesafe</code></pre><p>Then set an API key (<a href="https://console.typesafe.ai/">get one here</a>, the waitlist seems to move pretty fast):</p><pre><code>llm keys set typesafe# Paste key</code></pre><p>And now you can ask yes/no "noul" questions like this:</p><pre><code>llm -m jev 'Please refund my last payment.' \ -s 'Does this message explicitly request a refund?'</code></pre><p>Output:</p><pre><code>{"type": "noul", "noul": 0.99}</code></pre><p>Or choice questions like this:</p><div class="highlight highlight-source-shell"><pre>cat message.txt <span class="pl-k">|</span> llm -m jev \ -s <span class="pl-s"><span class="pl-pds">'</

<p>Last week <a href="https://typesafe.ai/">TypeSafe AI</a> unveiled <a href="https://typesafe.ai/blog/introducing-system-one-models-and-jev">Jev</a>, 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 href="https://twitter.com/Mappletons/status/2101560333441610133">a better name</a> 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 questions, ratings, and associated confidence scores.</p><p>TypeSafe describe Jev like this:</p><blockquote><p>Think of Jev as a frontier-intelligence function call: unstructured state in, typed probabilistic decisions out.</p></blockquote><p>It's also very fast, and <em>really cheap</em>. Regular LLMs <a href="https://www.llm-prices.com">are priced</a> in terms of input and output tokens, with output generally charged

<p><strong><a href="https://blog.cloudflare.com/python-workers-ga/">Cloudflare Python Workers are now generally available</a></strong></p>After a two year preview, Cloudflare's support for running Python code in their server-side Workers platform is now stable: "Python is now a first-class, fully supported language on the Cloudflare Developer Platform".</p><p>A neat thing about this is how it works. Cloudflare are running Python compiled to WebAssembly via Pyodide in their V8-based <a href="https://github.com/cloudflare/workerd">workerd</a> runtime.</p><p>This comes with some limitations, <a href="https://developers.cloudflare.com/workers/languages/python/stdlib/">documented here</a> - most notably both <code>multiprocessing</code> and <code>threading</code> are non-functional in the WebAssembly VM.</p><p>One particularly interesting detail of this is the local development environment story - their <a href="https://developers.cloudflare.com/workers/languages/python/#the-pywrangler-cli

<blockquote cite="https://twitter.com/v0xium/status/2101526107128529120"><p>It has been half a month since I started a new role at a big company. Nobody knows anything here. The specs, code, tests, PRDs, tickets, resolution of those tickets, reports, etc., everything is made by Claude Code. Nobody on my team likes this. They are being forced to ship as much as they can. I have heard multiple times from higher management that pushing code is not a bottleneck, so why are we slow? People are working 12 to 13 hours a day just to press enter. Nobody is reading anything. Everyone, literally everyone, from an L1 to an L7 engineer here is doing the same thing. Talk to Claude.</p></blockquote><p class="cite">&mdash; <a href="https://twitter.com/v0xium/status/2101526107128529120">voxium</a></p> <p>Tags: <a href="https://simonwillison.net/tags/ai-misuse">ai-misuse</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://sim

<p><a href="https://news.ycombinator.com/item?id=49779329#49779718">My comment</a> on <a href="https://news.ycombinator.com/item?id=49779329">MCP was always a bad idea?</a> &mdash; Hacker News.</p><p>This article entirely misses the value that MCP brings today.</p><p>Sure, there's almost no reason to use MCPs if you are running a full-blown terminal agent (Claude Code, Codex, Meta Muse, OpenClaw etc) with unfettered internet access - just let it call APIs directly.</p><p>If you want to operate something that's less YOLO than that, you'll find yourself wanting:</p><ol><li>Control over exactly which external services it can access</li><li>A way to handle authentication that doesn't allow the agent to directly access API keys</li><li>A sensible UI to allow users to connect and authenticate further services</li><li>Strong audit logging for what's going on</li></ol><p>MCP makes all of that so much easier to provide.</p><p>Thinking MCP is obsolete because full coding agents don't need it mi

<p><strong>Release:</strong> <a href="https://github.com/simonw/llm-keys-ui/releases/tag/0.1">llm-keys-ui 0.1</a></p> <p>This plugin solves a very specific problem.</p><p>I've started using <a href="https://learn.chatgpt.com/docs/remote">Codex Remote</a> to run coding agents on various machines while controlling them from my phone. </p><p>Sometimes I use those machines to hack on LLM projects, and occasionally that means I need to configure an API key.</p><p>I don't like pasting API keys into agent sessions, so I wanted a way to get those keys onto a machine without pasting them into the ChatGPT app directly.</p><p>With this plugin, I can tell Codex to run:</p><pre><code>uvx --with llm-keys-ui llm keys-ui --all</code></pre><p>Then have it tell me the URL - including local network or Tailscale device IPs - for an interface to save additional API keys.</p><p>Then later it can use a command like <code>llm keys get anthropic</code> as part of a shell command when it needs to use a key.</p

<p><strong>Release:</strong> <a href="https://github.com/simonw/datasette-explain/releases/tag/0.2.2">datasette-explain 0.2.2</a></p> <blockquote><ul><li>Explain plans now work on read-only stored-query pages.</li></ul></blockquote><p>I upgraded <a href="https://datasette.simonwillison.net">datasette.simonwillison.net</a> to Datasette 1.0a40, which inspired me to ship a new version of this explain plugin.</p> <p>Tags: <a href="https://simonwillison.net/tags/sqlite">sqlite</a>, <a href="https://simonwillison.net/tags/datasette">datasette</a></p>

<p><strong>Release:</strong> <a href="https://github.com/simonw/datasette-auth-github/releases/tag/1.0">datasette-auth-github 1.0</a></p> <p>I run this GitHub login plugin on the <a href="https://agent.datasette.io/">agent.datasette.io</a> demo site and I noticed that my authenticated sessions weren't lasting very long. It turned out that the plugin was setting cookies without a <code>Max-Age</code> parameter, so they were expiring at the end of a browser session (which in Mobile Safari seems to happen pretty often, independently of how you are using the app.)</p><p>I fixed that in <a href="https://github.com/simonw/datasette-auth-github/issues/80">#80</a> and, since this plugin has been around for quite a while and is tested against both Datasette 0.65.x and Datasette 1.0ax, I decided to bump it up to a 1.0 release. I'm trying to get better at promoting stable plugins to 1.0.</p> <p>Tags: <a href="https://simonwillison.net/tags/github">github</a>, <a href="https://simonwillison.net/t

<p><img src="https://static.inaturalist.org/photos/737061413/large.jpg" alt="California Sea Lion"></p><p><img src="https://static.inaturalist.org/photos/737061040/large.jpg" alt="Brandt&#x27;s Cormorant"></p><p>California Sea Lion, Brandt&#x27;s Cormorant, in Pillar Point Harbor, CA, US</p><p>I only noticed this after I had taken the photo: Morris <a href="https://simonwillison.net/2026/Aug/15/sighting-391300422/">the Northern Gannet</a> is peeking out from behind the base of the sign.</p> <p>Tags: <a href="https://simonwillison.net/tags/wildlife">wildlife</a></p>

<p><strong><a href="https://www.wsj.com/tech/ai/gemini-hacked-three-companies-in-first-known-breakout-by-googles-ai-5c0baba2">Gemini Hacked Three Companies in First Known Breakout by Google’s AI</a></strong></p>Gemini finally caught up on <a href="https://www.felonybench.com/">Felony Bench</a>!</p><blockquote><p>The hacks, which the company confirmed on Friday, occurred in May as part of a test run by the company Irregular, which was also involved in similar incidents disclosed by OpenAI, Anthropic and Meta.</p><p>In one of the cases, the model guessed passwords until it gained access to a protected system. In the other two cases, the model found credentials in a public repository that allowed it to then access protected systems. In each case, the model ended the intrusion after determining it had accessed a real company’s systems, Google said.</p></blockquote><p>Gemini is apparently less determined than other models, and decided <em>not</em> to keep going.</p><p>Google knew about the

<p>Being a computer scientist who refuses to find anything about LLMs interesting right now is a bit like being a geneticist who refuses to find anything interesting about the recently opened Jurassic Park.</p><p>Skeptical geneticist: "pfft, it's just frog DNA. And they deliberately let them eat people for the marketing."</p> <p>Tags: <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a></p>

<blockquote cite="https://twitter.com/trq212/status/2101009392611278961"><p>We're adding support for AGENTS.md to Claude Code. </p><p>Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md.</p><p>AGENTS.md support is built off of Claude Code mods, our upcoming way to customize the Claude Code harness.</p><p>This is a built-in mod, but you’ll be able to build custom versions of project instructions yourself as you’d like too.</p><p>You can see <a href="https://github.com/anthropics/claude-code/tree/main/mods/agents-md">the source for the mod here</a>!</p></blockquote><p class="cite">&mdash; <a href="https://twitter.com/trq212/status/2101009392611278961">Thariq Shihipar</a>, there are <a href="https://github.com/anthropics/claude-code/tree/main/mods">more mods here</a></p> <p>Tags: <a href="https://simonwillison.net/tags/thariq-shihipar">thariq-shihipar</a>, <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>

<p><strong><a href="https://blog.cypressf.com/post/828067789747208192/the-creative-spirit-of-who-framed-roger-rabbit">The Creative Spirit of Who Framed Roger Rabbit</a></strong></p>I love <a href="https://en.wikipedia.org/wiki/Who_Framed_Roger_Rabbit">Who Framed Roger Rabbit</a>, the 1988 movie by Robert Zemeckis. I haven't watched it in quite a few years, and Cypress Frankenfeld just pointed out this sequence from early in the movie:</p><p><video src="https://static.simonwillison.net/static/2026/pelican-bicicle-roger-rabbit.mp4" poster="https://static.simonwillison.net/static/2026-09-18/IMG_8118.jpeg" preload="none" loop controls playsinline muted width="886" height="480" style="display: block; width: 100%; height: auto;"></video></p><p>It's a pelican riding a bicycle!</p><p>Look closely and you'll note that the pelican is animated while the bicycle is a real bicycle. Apparently they filled the wheels with water to add stability, then set it running and guided it with a cable.</p><p>

<p><strong><a href="https://blog.rust-lang.org/2026/09/17/targeted-attacks/">Be alert: targeted attacks on prominent Rustaceans</a></strong></p>Important warning from Adam Harvey and the crates security team:</p><blockquote><p>We believe that there is an ongoing campaign targeting rust-lang members and owners of popular crates that is attempting to compromise devices and accounts in order to use them to publish malware.</p><p>A video call is set up for something positive — maybe for a job, maybe for a project, maybe for a contract opportunity — and then that's used as a vector to either get the target to install something on their computer (such as a purportedly missing audio codec) or execute another command (for example, via putting a command on the clipboard).</p></blockquote><p>Last month this trick was used in a successful <a href="https://blog.rust-lang.org/2026/08/20/supply-chain-attack-on-arrayref/">supply chain attack against the array ref crate</a>, among others.</p><p>Any p

<p><strong><a href="https://sockpuppet.org/blog/2026/09/17/how-to-write-with-an-llm/">How To Write With An LLM</a></strong></p>Thomas Ptacek on using LLMs as copyeditors, not as writing assistants:</p><blockquote><p><strong>Rule Number One: You may not use a single word an LLM suggests to you.</strong></p><p>[...] I think that as a form of intellectual personal protective equipment you should adopt the rule that any specific turn of phrase an LLM suggests is off limits. Be strict about the rule!</p></blockquote><p>I won't let LLMs write content for my blog, but I use them for fact-checking, spelling and grammar and as an occasional thesaurus (see <a href="https://simonwillison.net/guides/agentic-engineering-patterns/prompts/#proofreader">my proofreading prompt</a>).</p><p>The rule to never use a turn of phrase suggested by an LLM feels good to me. The text has that weird smell to it, and it's also a good principle to help stay disciplined.</p><p>Later in this piece Thomas shows a scre

<p><a href="https://news.ycombinator.com/item?id=49746618#49747390">My comment</a> on <a href="https://news.ycombinator.com/item?id=49746618">Bonsai 2 27B: Near-Lossless Compression in a 9x Smaller Footprint</a> &mdash; Hacker News.</p><p>If you want to try out out the GGUFs from <a href="https://huggingface.co/prism-ml/Ternary-Bonsai-2-27B-gguf#these-files-need-our-llamacpp-build">https://huggingface.co/prism-ml/Ternary-Bonsai-2-27B-gguf#th...</a> be aware that you need Prism's llama.cpp fork to get them to work, from <a href="https://github.com/PrismML-Eng/llama.cpp/releases/tag/prism-b10685-7dffb15">https://github.com/PrismML-Eng/llama.cpp/releases/tag/prism-...</a></p><p>This should work:</p><pre><code>cd /tmp# Get the Prism macOS runtimecurl -fL https://github.com/PrismML-Eng/llama.cpp/releases/download/prism-b10685-7dffb15/llama-prism-b10685-7dffb15-bin-macos-arm64.tar.gz -o bonsai-runtime.tar.gztar -xzf bonsai-runtime.tar.gz# Get the ~5.95 GB GGUF model:curl -fL https://hugging

<p><strong><a href="https://alignment.openai.com/misalignment-reports/self-generated-prompt-injections-in-compaction-summaries/">Self-generated prompt injections in compaction summaries</a></strong></p>In <a href="https://openai.com/index/model-misalignment-reporting-framework/">Our framework for reporting model misalignment</a> OpenAI provide "six reports on unexpected or concerning model behavior we’ve observed in the last six months". This one here is my favorite: they caught some of their models in training <em>deliberately subverting themselves</em> in their compaction prompts.</p><p>Compaction is the process agent systems use when they are running out of tokens in their context window, so they summarize everything that has gone before so they can keep going with more token headroom.</p><p>In one of the observed instances, a model undergoing reinforcement learning was working on a task to update an existing HTTP API endpoint with a new feature. The model compacted its work so far