The best Hacker News stories from Show from the past day
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Show HN: Parsimony – an open-source benchmark for how much code AI models add
Existing benchmarks measure solve rate and token output/cost, but don't punish excess code, which makes a codebase harder to work with in the long term. I wanted to measure this since it matters most for long-term projects.<p>Method: it takes the patches that benchmarks already publish (DeepSWE, SWE-bench Verified, SWE-bench Live) and counts "coding units": syntax elements like statements, calls, names and literals. I didn't use lines of code, so cramming code isn't rewarded. Deleted code is subtracted, so it measures net units.<p>GPT-6 and Claude 5.5 have no public patches yet, so I ran them myself on 3–10 tasks on my own subscriptions (shown as faded circles, not ranked).<p>Any feedback or model contributions are welcome, especially public patch exports for newer models.<p>GitHub: <a href="https://github.com/La5u/Parsimony" rel="nofollow">https://github.com/La5u/Parsimony</a><p>Not affiliated with any of the benchmarks.
Show HN: A guided 3D Leonardo da Vinci museum, built in code
Hello HN,<p>I am the founder of a small nonprofit which built Museum of Ages. We opened its first wing last week, a digital Leonardo da Vinci museum. It is a virtual tour with 17 stops, his works and then his last house in Amboise. The entrance is free.<p>At the different stops you can see for example his paintings close to their real size, or 15 of his machines rebuilt in code, and you can have a look at 29 of his anatomy sheets. We also selected 207 of his manuscript pages which you can read in a virtual reading table, mirror the view to read his writing and 131 of the 207 are translated. We also rebuilt his last house in Amboise on the later stops of the walk. The museum is available in seven languages.<p>Each stop has one of four grades as a label, documented, reconstructed, conjectural and not known. In a detailed view the user can have a closer look at the sources.<p>The materials of the rooms and machines are created in Three.js. The museum runs with WebGPU. If the browser doesn’t support it, the fallback is WebGL2. To create the textures we used Creative Commons Zero photo scans (CC0) and for a few small objects we use free 3D models (CC0).<p>Our mission is to create digital museums you can walk as not everyone can get to a museum, because illness or disability keeps them away. Some cannot afford the trip or just reside far away. So our goal is also to make our digital museums as accessible as possible. Therefore we also pre-rendered the walk so that it also works on older phones and is easy to use for older people.<p>We released the code under AGPL-3.0. The texts and pictures are CC BY-SA 4.0. Reproductions have their own licenses.
<a href="https://github.com/chipmates/museumofages" rel="nofollow">https://github.com/chipmates/museumofages</a><p>We put a lot of time and passion into the museum and hope you like it. We are happy about any feedback. Which digital museum would you like to see next?
Show HN: I wrote an email app that accepts only one sender per inbox
Infinite inboxes, including prefixes where you don't have to create inboxes before you use them -- they self create when you add a suffix.<p>Three types of inboxes:
- One sender. Locks to the first domain to send email (except gmail, outlook, etc where it locks to an email account for obivous reasons. It bounces everyone else.
- Temporary. Lasts for a while (24h, 7days, etc) then bounces. Received messages stay or go as per your choice.
- Prefix. The most powerful. Declare a prefix like "service" and then invent any suffix, like "service-netflix" or "service$bank" and it creates a new one-sender inbox locked to whoever wrote first.<p>Bring you own domain. Bring your own AI (MCP server ready). Forwarding.<p>Please help me test it.
Show HN: Petal, open-source CoScreen/ScreenHero finally free
Hi HN!<p>I’m Jason Thomas, one of the founders of CoScreen.<p>As some of you may know, Datadog sunset the CoScreen service on July 31st.<p>Four of us from the original CoScreen team have spent the last couple months building a free and open source pair programming tool inspired by those that came before us: It’s called Petal (<a href="https://github.com/kiruna-labs/petal" rel="nofollow">https://github.com/kiruna-labs/petal</a>)<p>Some history first, because when we started CoScreen we had hoped to break the sad and established pattern of this industry.<p>Screenhero was an exceptional tool that a lot of us loved for pairing. Multiple cursors, low latency, you could click your partner’s editor, and just start typing. It felt like magic while we had it. Then Slack bought it in 2015, and shut down the standalone app in December 2017.<p>When Till, Max, and I started CoScreen, we were aware of this history, and wanted to build an even more magical collaboration and screen sharing experience: the entire concept was “throw a window from your laptop up on someone else’s screen, and start collaborating with zero friction.”<p>Datadog acquired us in 2022, and thus began the great adventure of adapting our real-time technology into Datadog products, while also continue developing CoScreen as a standalone tool from the Datadog ecosystem. Datadog invested in the product for years and we’re thankful for that. But CoScreen itself proved, like so many other screen sharing tool acquisitions, to be too tangential from the customer base and core mission. We instead built other communication features in Datadog, the integrations with other video platforms, and also its wildly successful MCP server.
We weren't the only ones. Around was bought by Miro and shut down in March 2025. Multi (formerly Remotion) was acqui-hired by OpenAI in 2024 and shut down about a month later. It's nearly always the same story: a small team builds something hard that people love, a platform buys it for the team or the feature, and the standalone product doesn't survive the integration.
So we decided firmly to do things differently this time. Petal is completely free and open source and we aren't monetizing it. If we lose interest or get hit by a bus, you can self-host it or fork it, and nobody can sunset it on you. Honestly it's a love letter to everyone in this community that supported us, believed in us, and to liberate collaborative screen sharing from this vicious cycle.<p>We hope through this we can help foster a large and vibrant community around innovating in this product sector.
What Petal does: shared windows show up as real windows on your desktop, movable and resizable, not tiles in a grid. Several people can share at once, everyone gets a labeled cursor, and you can click into any shared window to type and scroll. Rooms are persistent, so you click once to join "eng-sync" instead of passing links around.
It runs on macOS and Windows (Linux is next, this time for real and you can help us!), plus a web app. Media goes over LiveKit. You can use our hosted instance with zero config, or point the app at your own LiveKit server with one docker-compose if you want the traffic to stay on your network or even use an entirely different video backend if you want to.
The part that still feels strange to us: CoScreen took almost six years to build. The first version of Petal took under eight weeks, from scratch, with frontier models like Fable and Astra doing a lot of the work. Real-time video and window capture is some of the most unforgiving code we have ever written, so we didn't expect that. We will do a proper writeup on what worked and what didn't, and are happy to answer questions about it here.
Till, Darren, Max and I will be in the thread.
Show HN: Pulse Local, a Mac budgeting app whose AI models run on your machine
Hi HN, I'm Niz. Pulse Local is a budgeting app for Mac (Apple Silicon, beta) that answers questions about your spending with models that run on your machine. Local mode needs no account. The ledger and your questions stay on the machine, and the app sends no analytics or crash logs.<p>I felt there are not enough consumer apps that run locally with no calls to the outside world that help us manage sensitive corners of our lives. This app in its local variant only downloads a couple of models and occasional updates, it does not send any analytics nor data.<p>Features-wise, Pulse local is a complete budgeting app that offers an assistant built on top of a fine-tuned model and thousands of rules embedded in the code itself. I'm sharing it for free with options to help me continue experimenting with fine-tuning and expanding along this direction.<p>How it works: you import a CSV from any bank, in any currency. When you ask a question, a tuned Qwen3 0.6B model reads it into a structured query, and code, not the model, does the money math against the ledger. A 4B checker model double-checks each money answer; when the two readings disagree, the app says it is not sure instead of guessing. That change took wrong answers from about one in five to 5 in 494 questions across our last three tests. The write-up covers how we test, the designs that failed, and the limits of the claim: <a href="https://pulseos.finance/pulse-local/writing/agree-or-not-sure" rel="nofollow">https://pulseos.finance/pulse-local/writing/agree-or-not-sur...</a><p>The tuned weights are on Hugging Face (PulseOS/pulse-local-qwen3-0.6b).<p>Limitations: the first start downloads about 2.9 GB of models. With the checker on, a money answer takes 12 to 14 seconds (you can turn the checker off). Small models can still misread an open-ended question. The app answers in English. Mac only for now; Windows is next.<p>The app is free. An optional Connected mode (Sync Pass, $29/year) syncs US banks through Plaid; transactions pass through our server's memory and are not stored.<p>Feedback welcome, especially on wrong answers and on questions it should handle but does not.
Show HN: I built a tool to track what AI leaders say and how their views change
Show HN: Spotatui, a Spotify TUI/GUI without web API rate limits
About 11 months ago i revived the amazing but unfortunately unmaintained spotify-tui. Since then I have been working on it almost non stop, finding a lot of problems on the way.<p>One of the main issues I ran into were the Spotify web API rate limits. Third party clients like spotatui are dependent on a developer app made in the Spotify developer dashboard, which get rate limited a lot and Spotify has slowly been deprecating endpoints from it. The workaround for this used to be using a shared client id from ncspot but unfortunately that got rate limited too. This is when i started adding other playback sources, including YouTube, Navidrome/Subsonic, Internet radio with +- 30.000 stations, local files, Qobuz for lossless audio and Apple Music for macOS only where it controls the music app remotely.<p>I fixed both the deprecated endpoints and the rate limits with one solution. It still uses librespot in the back, my spotatui specific fork, but gets all data from it instead of only playback. The data comes from the internal API of the official clients, that API gives metadata, playlists, the user library, devices, lyrics and audio analysis. For searching it uses Pathfinder, the internal GraphQL API.<p>There are no web API rate limits because there is no shared app quota. Every user uses their own session as if it was the official client. The only potential problem is that Spotify does not document this API so any change on their side would break it. I intend to fix any of those issues as soon as they pop up.<p>It all started as a TUI back in 2019 but since then I've added a GUI to it too. The GUI is still a bit behind the TUI in terms of features, it only ships Spotify for now, but full parity between the TUI and GUI is coming soon. After that full parity with the official client is next. That is also why I made the GUI looks almost the same as the official client. That way its easier for me and users to find missing features.<p>Spotatui also has lua scripting support, a optional Web companion on spotatui.com, and if you have a AI coding agent like ChatGPT codex or Claude Code you can enable the MCP tools, which lets AI become your personal DJ just by talking to it.<p>Its written in Rust, uses ratatui for the terminal UI and Tauri 2 for the GUI. The Rust core starts a small web server with localhost that only your pc can reach which the GUI then serves. Both frontends share the same playback logic, the same login and the same Spotify code. The only difference is how you interact with it.<p>On first launch it opens a web browser where you need to login with your Spotify premium account (premium is not optional), that is the whole setup done. I would love any feedback about bugs you encounter or features you would like to see.
GitHub: <a href="https://github.com/LargeModGames/spotatui" rel="nofollow">https://github.com/LargeModGames/spotatui</a>
Releases: <a href="https://github.com/LargeModGames/spotatui/releases/latest" rel="nofollow">https://github.com/LargeModGames/spotatui/releases/latest</a>
Website: <a href="https://spotatui.com/" rel="nofollow">https://spotatui.com/</a><p>Thanks to librespot for making this all possible
Show HN: Opensidian
Show HN: XY Music Notation
I've been playing around with a new kind of isomorphic music keyboard that uses a base-12 notation, and wanted some sheet music to learn some new music for it.<p>The idea is to represent each note in 12-TET as a number, so N ∈ (0,1,2,3,4,5,6,7,8,9,X,Y).<p>I used codex to build a music score rendering backend based on MuseScore with custom note heads that display the pitch class of each note.<p>I've found it pretty helpful for learning how to play my own instrument, so wanted to share in case anyone else was interested.
Show HN: XY Music Notation
I've been playing around with a new kind of isomorphic music keyboard that uses a base-12 notation, and wanted some sheet music to learn some new music for it.<p>The idea is to represent each note in 12-TET as a number, so N ∈ (0,1,2,3,4,5,6,7,8,9,X,Y).<p>I used codex to build a music score rendering backend based on MuseScore with custom note heads that display the pitch class of each note.<p>I've found it pretty helpful for learning how to play my own instrument, so wanted to share in case anyone else was interested.
Show HN: How Random Are You?
Show HN: How Random Are You?
Show HN: An experimental pattern-first DAW that supports MCP
Show HN: SolidCraft – Open-Source Parametric CAD in Rust (With MCP Support)
Show HN: Use your OpenAI subscription to create audiobooks
Show HN: Use your OpenAI subscription to create audiobooks
Show HN: Guitoro, a virtual guitar you strum with your keyboard
Guitoro is a free browser guitar using recordings of real instruments. You can strum with your keyboard, mouse, or touchscreen, choose acoustic, classical, electric guitar or bass, and see chord fingering and each stroke. Song practice can be slowed to 20%, and there are free chord tools and tuners. No signup or download.<p>1 minute video demo: <a href="https://youtu.be/DtcluMLdSgs" rel="nofollow">https://youtu.be/DtcluMLdSgs</a><p>I would love feedback on how the strumming feels and sounds.
Show HN: Guitoro, a virtual guitar you strum with your keyboard
Guitoro is a free browser guitar using recordings of real instruments. You can strum with your keyboard, mouse, or touchscreen, choose acoustic, classical, electric guitar or bass, and see chord fingering and each stroke. Song practice can be slowed to 20%, and there are free chord tools and tuners. No signup or download.<p>1 minute video demo: <a href="https://youtu.be/DtcluMLdSgs" rel="nofollow">https://youtu.be/DtcluMLdSgs</a><p>I would love feedback on how the strumming feels and sounds.
Show HN: GeoRadios – Spin a globe, hear what's on the radio there
Show HN: Plimsoll, a self-hosted sandbox for code your AI agent writes