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Structure and Interpretation of Computer Programs Video Lectures (1986)

Git Hash Chain Malleability

Show HN: OCR Buddy: local browser OCR for code, formulas (LaTeX) and tables

Waymo reports teen riders for bad behavior and delivers them to the police

Every new car sold in the European Union must include a driver monitoring camera

We charge $10k a week to delete AI-generated code

Show HN: Tessera – an AI agent that refuses to answer without evidence

Show HN: Davit, a Apple Containers UI Mostly vibe-coded Apple Containers front-end that I'd like to use myself. But if others want to use it, here's the source code.

AI Meets Cryptography 1: What AI Found in Cloudflare's Circl

Show HN: Docx-CLI: agents read/edit Word docs using 1/2 the time and tokens

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Biff.graph: structure your Clojure codebase as a queryable graph

China sentences official to death for taking $325M in bribes

Reducing Doom Loops with Final Token Preference Optimization

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Almost all coders at Id Software have been fired, following Xbox reset

Show HN: Halo – open-source, tamper-evident runtime evidence for AI agents Hi HN, I&#x27;m Brian, I spent the last few years at Vanta (YC W18), helping startups and enterprises become compliant and I recently started exploring what that might look like in a post-agentic world.<p>The problem Halo solves is: when a company buys an AI agent from a vendor and gives it access to their data, they have no way to check what the agent did with that data. Vendors may have built observability dashboards and audit logs, but those are editable and partisan. SOC 2 and ISO 27001 audit a company&#x27;s controls, but controls are less predictive when the software is agentic. TLDR: give an agent the same prompt 50 times, and you get 50 slightly different actions&#x2F;answers - so the only thing worth auditing in a post-agentic world is what happened at runtime.<p>Halo is an open-source project that produces agent runtime evidence. It&#x27;s a small recorder that records every action an agent takes (eg. tool calls, model calls, data access, etc), and becomes a record in an append-only log. It&#x27;s hash-chained, so anyone can re-verify.<p>Run the following command to see a fictional example:<p><pre><code> uvx --from halo-record halo demo --serve </code></pre> Then, delete a line from one of the .jsonl files and reload, and the report will catch that it&#x27;s been tampered with.<p>To wire up your own agent, run this line of Python:<p><pre><code> agent = trace(run_my_agent, profile=&quot;my-agent&quot;, log=&quot;audit.jsonl&quot;) </code></pre> Then use this to generate a real report and give it to your customers:<p><pre><code> halo report audit.jsonl -o report.html </code></pre> Disclaimer: this proves integrity, not completeness (as a self-held chain proves nothing was edited but does NOT prove that nothing was omitted). Catching this requires a witness outside the vendor and is what I&#x27;m working on next.<p>Halo is Apache-2.0, contains zero runtime dependencies, and is about 4,300 lines of Python with 125 tests (if you prefer TypeScript, here&#x27;s that repo: <a href="https:&#x2F;&#x2F;github.com&#x2F;bkuan001&#x2F;halo-record-ts" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;bkuan001&#x2F;halo-record-ts</a>).<p>Give it a try, and please let me know if you have any feedback!

Show HN: Yamanote.fun – A complete soundscape for Tokyo's Yamanote line After visiting Japan for the first time a decade ago I became completely enamoured with Tokyo&#x27;s Yamanote Line railway loop. Particularly the sonic experience of it. Like so many others I fell in love with the charming departure melodies and enjoyed discovering experiences like Yamanot.es (<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=45045307">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=45045307</a>) here on Hacker News when I returned home.<p>But it wasn&#x27;t until my second trip to Tokyo that I truly appreciated how much the door chimes, on-board announcements and train noise were contributing to the rich soundscape that I loved.<p>I returned home and found myself playing YouTube videos of Yamanote Line journeys as I worked. The combination of sonics, ambience and softly spoken Japanese was incredibly soothing to me.<p>But these recordings were often incomplete, poorly captured or out of date, and I wanted something far more comprehensive.<p>So I gathered up all of the constituent parts from Reddit threads, YouTube videos and Japanese fan sites, and set about recreating the experience of riding the Yamanote Line in Logic Pro X. Melody, door chimes and announcement, all stitched together under a bed of train noise and ambience.<p>I turned those soundscapes into an Alexa Skill (<a href="https:&#x2F;&#x2F;www.amazon.co.uk&#x2F;Paul-Jackson-Yamanote-Line&#x2F;dp&#x2F;B07S18QRMV" rel="nofollow">https:&#x2F;&#x2F;www.amazon.co.uk&#x2F;Paul-Jackson-Yamanote-Line&#x2F;dp&#x2F;B07S1...</a>) in 2019 and began to think about a companion website to share the soundscapes with a wider audience.<p>Seven years later and that website is Yamanote.fun: <a href="https:&#x2F;&#x2F;www.yamanote.fun&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.yamanote.fun&#x2F;</a>.<p>It&#x27;s a small installable web app that plays the soundscapes like a playlist. All 30 stations and in both directions, since the inner and outer loops use different melodies. You can skip forward or back a station, and there&#x27;s a scrub bar broken into melody &#x2F; chime &#x2F; ambience &#x2F; announcement so you can jump straight to the bit you want. Each station has its own shareable link (yamanote.fun&#x2F;jy13-ikebukuro-inner) that unfurls with the right station name and artwork when you share it.<p>It&#x27;s a progressive web app too, so you can add it to your home screen and it behaves like a native app. There&#x27;s an option to offline the audio too.<p>Under the hood it&#x27;s relatively basic stuff: plain HTML, CSS &amp; JS, audio served from Cloudflare R2 and the site hosted on Netlify. I was impressed to see how far I could get with the free tiers of these services. I designed the whole thing in Figma (I&#x27;m a Product Designer) and used Claude Code to architect and deliver the polished UI, PWA plumbing, offline caching and share-link infrastructure.<p>I would love feedback, particularly from anyone who&#x27;s ridden the real thing.

A better way to tie your gym shorts. (Or any drawstring) [video]

Show HN: PostgreSQL performance and cost across 23 EC2 instance types Hey! I&#x27;m Andrei.<p>I got frustrated by how people tend to build overcomplicated backend systems, being &quot;motivated&quot; by big tech case studies and popular books.<p>So, I started exploring lean architecture, and building my digital garden of ideas, approaches and data that align with this direction.<p>Here I want to present one of the tools – Sizing tool for PostgreSQL. I&#x27;ve benchmarked PostgreSQL on different EC2 instances and disks, with different initial data sets to see performance that these instances can give you. And I&#x27;ve built a tool to visualize this data, which I welcome you to explore.<p>So, you can put your usual input parameters, like needed RPS and disk size as input, and find out which instance will be the most cost-efficient for your needs.<p>You can read about the methodology here: <a href="https:&#x2F;&#x2F;postgres.saneengineer.com&#x2F;about" rel="nofollow">https:&#x2F;&#x2F;postgres.saneengineer.com&#x2F;about</a><p>I&#x27;ve tested one workload – mixed 90&#x2F;10 read&#x2F;write, and only selected configurations. But it is extensible, and I (and you – benchmark is open source: <a href="https:&#x2F;&#x2F;github.com&#x2F;anivaniuk&#x2F;sanebench" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;anivaniuk&#x2F;sanebench</a>) can run more configurations to have more data represented.<p>Does it look interesting? What workload should I benchmark next?