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Show HN: Cactus Hybrid: We taught Gemma 4 to know when it's wrong
Hey HN, Henry & Roman here from Cactus.<p>A small, on-device model is fast and private, but sometimes wrong, but frontier models are getting expensive pretty fast. So, we post-trained Gemma 4 E2B post-trained to know when it's wrong. Every response comes with a confidence score between 0 and 1. Developers can accept the on-device when it's high, hand off to a bigger cloud model when it's low. By routing only 15-35% of queries to Gemini 3.1 Flash-Lite, Gemma-4-E2B matches Gemini 3.1 Flash-Lite on most benchmarks.<p>- ChartQA: 15-20%<p>- LibriSpeech: 25-30%<p>- MMBench, GigaSpeech, MMAU: 30-35%<p>- MMLU-Pro: 45-55%<p>We were always frustrated by the routing signals hybrid apps rely on: asking the model to rate itself in text (unreliable, and you're parsing prose), or token entropy heuristics (barely better than a coin flip in our tests). So we did mechanistic studies on small models, Gemma 4 particularly, and found the hidden state for different layers carry meaningful self-awareness signal for various situations.<p>SO we extended the model with a 68k params probe layer (LayerNorm, low-rank projection, attention pooling, small MLP head) reads one intermediate layer during decoding and predicts p(wrong); confidence = 1 - p(wrong), returned as structured data, never parsed out of the answer text.<p>Across 12 hold-out benchmarks spanning text, vision and audio, the probe averages 0.814 AUROC vs 0.549 for token entropy. The result that convinced us this is real: the probe was trained on zero audio data, yet scores 0.79-0.88 AUROC on four audio benchmarks where entropy is near-random or worse (0.32-0.52). It's reading a modality-independent correctness signal from the hidden state, not memorizing patterns from its training data.<p>We published all weights on HuggingFace and provide copy-pase codes to run it on Transformers, MLX, Llama.cpp or Cactus. With Ollama, vLLM, SGLang etc in the works. For llama.cpp we ship a patch series you compile in once (upstreaming is planned). The code is MIT licensed; Gemma model use remains subject to the Gemma terms.<p>GitHub: <a href="https://github.com/cactus-compute/cactus-hybrid" rel="nofollow">https://github.com/cactus-compute/cactus-hybrid</a><p>Weights: <a href="https://huggingface.co/collections/Cactus-Compute/cactus-hybrid-6a60da4551074db058e8bb64" rel="nofollow">https://huggingface.co/collections/Cactus-Compute/cactus-hyb...</a><p>Some caveats:<p>- The probe scores single-sequence decoding only, up to the first 1024 generated tokens.<p>- Handoff works best when routing per task in a multi-step process, not per step.<p>- Hierarchical routing is still in the works: try on-device, then DeepSeek v4 Flash, before Fable/GPT5.5/Gemini/Muse/Grok.<p>- The technique is boutique for each model, we will share each weights as they roll out.<p>These issues are currently being tackled at Cactus and updated weights will be shipped directly into the HuggingFace collection and GitHub repository straight up. Please let us know your thoughts, it helps us find ways to improve the design progressively.<p>Thanks a million!
Show HN: Web swing through midtown NYC
Show HN: A new kind of FPS aim trainer
I played a lot of Valorant and got mad, so I made an aim trainer that analyzes your raw crosshair movement to explore your raw motor and perceptual weaknesses instead of scoring scenarios.
It also chooses sens and difficulty as part of the tasks, and makes playlists that are optimal difficulty for you to learn and progress faster!
Show HN: ReadKinetic – a free, local-first speed reader for your own books
Show HN: HN Hall of Fame – browse 3,100 legendary Hacker News links
Show HN: Bento - An entire PowerPoint in one HTML file (edit+view+data+collab)
Over the past few months, our team has been building more and more slidedecks using web frontend technologies with coding harnesses like Claude Code, but a common complaint is to make even small edits we need to edit the code either manually or via the harness.<p>To avoid this loop, I ended up creating Bento, a single HTML file with everything you need in a slide tool including animations and shared editing. There's no install or cloud login, everything works offline. The default deck is around 560 KB and it doesn't need to fetch anything once you got it.<p>Open it in a browser and then you can edit, present, print and save. Share it via email or via Airdrop and all they need is a browser to edit, present and also do live collab on the slides. Drop it in to Claude or ChatGPT to transform existing pptx files into Bento slides. There is no cloud involved, only an encrypted blind relay to allow for shared editing. The relay doesn't see any of the data.<p>Check it out at <a href="https://bento.page/slides/" rel="nofollow">https://bento.page/slides/</a> which takes you straight to the editor.<p>Go to <a href="https://bento.page/guestbook/" rel="nofollow">https://bento.page/guestbook/</a> to try out the live guestbook to experience share editing / collab.<p>There is also a gallery with some sample decks on the website - <a href="https://bento.page/" rel="nofollow">https://bento.page/</a><p>All the code is MIT licensed and you can find it here - <a href="https://github.com/nyblnet/bento" rel="nofollow">https://github.com/nyblnet/bento</a> . I used reveal.js with several other libraries (including some homegrown ones), and Claude Code.
Show HN: Explore 6048 YC companies as an interactive galaxy
Show HN: CodeAlmanac – Karpathy-style codebase wiki from your conversations
Hey HN! This is Divit from Almanac (YC S26). We built CodeAlmanac, a wiki for your coding agents that updates as you talk to them. It is open-source, local, and free.<p>Here’s a demo: <a href="https://www.youtube.com/watch?v=XNQWV3TFBWM" rel="nofollow">https://www.youtube.com/watch?v=XNQWV3TFBWM</a><p>Your CC/Codex conversations contain a LOT of knowledge that is forgotten because it was never documented. People have their own methods of documenting their chats. We used to make Markdown files like MANUAL.md and DESIGN.md, and would prompt Claude to keep them updated. The problem is that these files quickly become outdated and messy, and there’s only so much you can put in a single file.<p>So we set out to build CodeAlmanac. We wanted something that was 1) maintained automatically, 2) lived inside our repository, and 3) used our existing Codex/Claude Code subscriptions.<p>CodeAlmanac maintains an almanac/ folder inside your repository. It contains connected Markdown pages that cover things not documented in the codebase, including decisions you have made and why the codebase is shaped this way.<p>The pages are indexed in SQLite and are queryable through a CLI. We add instructions to AGENTS.md or CLAUDE.md so future sessions automatically search the wiki before they start coding.<p>Every five hours, CodeAlmanac uses the Codex/CC SDK to spin up an agent that reads your new conversations and updates the relevant pages. We went with a time-based trigger instead of commits because we saw people commit very frequently, which would lead to high token costs.<p>We originally made CodeAlmanac for individual developers, but the team use case has become much more obvious to us while using it ourselves. We are a team of three, and each of us works with our own coding agents. Before this, I would make some change after a lot of thinking and then later have to call my cofounders and explain why it looked this way. There is almost a sense of relief now knowing that the decisions I made are written down somewhere their agents will actually read.<p>It’s live today for everyone to try. Please let me know your feedback and I’ll be here to answer any questions. Would also love to hear how you all maintain context across conversations today!
Show HN: Imagin Raw – A 9MB Open-Source Alternative to Adobe Bridge for Mac
Show HN: Imagin Raw – A 9MB Open-Source Alternative to Adobe Bridge for Mac
Show HN: Read the Tape – Wordle for daytrading, five blind S&P 500 charts a day
Read the Tape gives players the same 5 S&P500 stock charts per day to predict. You select low, medium or high confidence and then call the chart UP or DOWN. It's a 1d chart which then resolves over 5 days. Alpha is scored against the Monkey Index, a basket of 11 random coin flips at low confidence which provides a tangible win/lose condition.<p>We're two weeks in and some interesting data is being kicked up. Players like to call tops even though stonks go up- 60% of the 70 charts so far resolve higher, players' down calls have only been right 31% of the time. There's a full stats dive at <a href="https://readthetape.cc/notes/tape-report-1" rel="nofollow">https://readthetape.cc/notes/tape-report-1</a><p>Your feedback and thoughts is most welcome.
Show HN: Read the Tape – Wordle for daytrading, five blind S&P 500 charts a day
Read the Tape gives players the same 5 S&P500 stock charts per day to predict. You select low, medium or high confidence and then call the chart UP or DOWN. It's a 1d chart which then resolves over 5 days. Alpha is scored against the Monkey Index, a basket of 11 random coin flips at low confidence which provides a tangible win/lose condition.<p>We're two weeks in and some interesting data is being kicked up. Players like to call tops even though stonks go up- 60% of the 70 charts so far resolve higher, players' down calls have only been right 31% of the time. There's a full stats dive at <a href="https://readthetape.cc/notes/tape-report-1" rel="nofollow">https://readthetape.cc/notes/tape-report-1</a><p>Your feedback and thoughts is most welcome.
Show HN: Ex Situ – Open-source spatial index of displaced cultural artifacts
Hi, I designed and developed a spatial index that maps museum artefacts as connecting arcs/hyperlinks from their origin site to institutional location/sources. The Index specifically looks at western/euro-american institutions and maps their collection categorised by them under Islamic art, Asian/African art, ethnological collections, Middle East, South America etc.<p>Started as my MA thesis in 2022, kept building since, mostly solo with a little funding. Fully open source, self-hosted, AGPL-3.0, Next.js + Deck.gl on the frontend, Strapi backend, Python ETL pulling from museum open-access APIs. Currently indexing over 100k artifacts from all over the world, across 8 collections (Met, V&A, SMB Berlin). Recently added an md export so researchers can download provenance data for a filtered set of artifacts.<p>The infrastructure is conceptualized as an indexer, not a hoster. Even images are kept as URLs pointing to the source institutions. It's connective tissue between archives that were never designed to speak to each other, with an origin-first search UI concept. The data model is on purpose flat, to avoid encoding problematic taxonomies, and routes researchers directly to the source giving responsibility to the source institutions rather than duplicating institutional data. It indexes the relationship between origin sites and destination collections.<p>Coming from a design background, taking this project from prototype to production app has been incredibly rewarding, but honestly it’s getting a little bit overwhelming to scale alone. I would love community’s feedback on performance scaling, any code contributions, data pipelines for missing museum apis or general feedback.<p>Repo: <a href="https://github.com/hburakyel/ex-situ" rel="nofollow">https://github.com/hburakyel/ex-situ</a><p>Live: <a href="https://exsitu.app" rel="nofollow">https://exsitu.app</a>
Show HN: Justif – Knuth-Plass justification and microtypography for the web
Justif is a drop-in JavaScript library that progressively enhances web pages to TeX-level text justification. Installation is a single <script> line, standard text and accessibility affordances are unchanged, and users with JS disabled get native browser rendering.<p>I made justif because I've long been a fan of justified text. I think it looks clean and elegant, and makes reading more enjoyable. But bad justification is the opposite, with gaping spaces that distract me to the point of making the text near unreadable.<p>Browsers have got better recently at handling justified text [0][1], but still use suboptimal greedy algorithms for the most part, and are not near that TeX/InDesign level of quality that I crave. `text-wrap: pretty` exists but is far from a panacea, as you can see for yourself in the demo.<p>Justif also has the benefit of providing more consistent text layout across browsers. Blink (Chrome), Gecko (Firefox) and WebKit (Safari) all justify text differently, so normally what the user sees depends on what browser they use.<p>Take a look at the demo, play around with it, see if you can break anything. I'm open to improvements of the API design as well, so please let me know your thoughts.<p>For more details, see the README: <a href="https://github.com/lyallcooper/justif" rel="nofollow">https://github.com/lyallcooper/justif</a><p>0: <a href="https://cloudfour.com/thinks/justified-text-better-than-expected/" rel="nofollow">https://cloudfour.com/thinks/justified-text-better-than-expe...</a><p>1: <a href="https://owickstrom.github.io/the-proportional-web/" rel="nofollow">https://owickstrom.github.io/the-proportional-web/</a>
Show HN: Justif – Knuth-Plass justification and microtypography for the web
Justif is a drop-in JavaScript library that progressively enhances web pages to TeX-level text justification. Installation is a single <script> line, standard text and accessibility affordances are unchanged, and users with JS disabled get native browser rendering.<p>I made justif because I've long been a fan of justified text. I think it looks clean and elegant, and makes reading more enjoyable. But bad justification is the opposite, with gaping spaces that distract me to the point of making the text near unreadable.<p>Browsers have got better recently at handling justified text [0][1], but still use suboptimal greedy algorithms for the most part, and are not near that TeX/InDesign level of quality that I crave. `text-wrap: pretty` exists but is far from a panacea, as you can see for yourself in the demo.<p>Justif also has the benefit of providing more consistent text layout across browsers. Blink (Chrome), Gecko (Firefox) and WebKit (Safari) all justify text differently, so normally what the user sees depends on what browser they use.<p>Take a look at the demo, play around with it, see if you can break anything. I'm open to improvements of the API design as well, so please let me know your thoughts.<p>For more details, see the README: <a href="https://github.com/lyallcooper/justif" rel="nofollow">https://github.com/lyallcooper/justif</a><p>0: <a href="https://cloudfour.com/thinks/justified-text-better-than-expected/" rel="nofollow">https://cloudfour.com/thinks/justified-text-better-than-expe...</a><p>1: <a href="https://owickstrom.github.io/the-proportional-web/" rel="nofollow">https://owickstrom.github.io/the-proportional-web/</a>
Show HN: A self-running space economy SIM in Rust and Bevy
I built this with Claude cause I always wanted to tinker with a simulation economoy and I love space themes.<p>A space-economy sim where nothing is scripted. A few hundred autonomous ships each run their own planner. Some chase the best trade route, take a delivery contract, refuel, retrofit at a shipyard, or dock so the crew can rest before morale tanks.<p>Markets price everything off supply with shortage-urgency multipliers, factions tax and subsidize, populations migrate when they're unhappy, and stations that go broke get abandoned and rot.<p>It started as an Elixir/Phoenix prototype, but the BEAM scheduler struggled on Windows gaming PCs, so I had Claude rewrite the engine in Rust.<p>The sim core is pure, synchronous, IO-free (its own hecs ECS), and the Bevy client embeds it directly as a library, sim and renderer share one world with zero marshalling. Ship AI is a GOAP planner over a world state; ships replan mid-flight when a better option appears. ~485 agents today at p50 ~10-20ms/tick, architected to push toward 100k+. Single native binary, bundled SQLite, no runtime deps. Getting into 100k has been a struggle, but I have pushed it into the thousand and it was running fine.<p>It's a sandbox, not a game yet, there's no objective yet, and I'm not actively pushing it toward "shippable." Anyone can fork it and take it over. Or it can stay as some type of AI slop, but part of me thinks it is already in a pretty good shape for a simulation use for various games or ideas.<p>(Full disclosure: a lot of this was built pairing with Claude. That's how I had the bandwidth to take it this far. Happy to talk about what that workflow actually looked like.)
Show HN: A self-running space economy SIM in Rust and Bevy
I built this with Claude cause I always wanted to tinker with a simulation economoy and I love space themes.<p>A space-economy sim where nothing is scripted. A few hundred autonomous ships each run their own planner. Some chase the best trade route, take a delivery contract, refuel, retrofit at a shipyard, or dock so the crew can rest before morale tanks.<p>Markets price everything off supply with shortage-urgency multipliers, factions tax and subsidize, populations migrate when they're unhappy, and stations that go broke get abandoned and rot.<p>It started as an Elixir/Phoenix prototype, but the BEAM scheduler struggled on Windows gaming PCs, so I had Claude rewrite the engine in Rust.<p>The sim core is pure, synchronous, IO-free (its own hecs ECS), and the Bevy client embeds it directly as a library, sim and renderer share one world with zero marshalling. Ship AI is a GOAP planner over a world state; ships replan mid-flight when a better option appears. ~485 agents today at p50 ~10-20ms/tick, architected to push toward 100k+. Single native binary, bundled SQLite, no runtime deps. Getting into 100k has been a struggle, but I have pushed it into the thousand and it was running fine.<p>It's a sandbox, not a game yet, there's no objective yet, and I'm not actively pushing it toward "shippable." Anyone can fork it and take it over. Or it can stay as some type of AI slop, but part of me thinks it is already in a pretty good shape for a simulation use for various games or ideas.<p>(Full disclosure: a lot of this was built pairing with Claude. That's how I had the bandwidth to take it this far. Happy to talk about what that workflow actually looked like.)
Show HN: Stacks – an hourly card solitaire about building four gardens
Show HN: Wheesper – Start an anonymous discussion with a link
Show HN: Wheesper – Start an anonymous discussion with a link