TLDR Index
TLDR Dev

TLDR DEV 2025-11-27

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01ARTICLES & TUTORIALS

BUILDING A 64-BIT OS FROM SCRATCH WITH CLAUDE CODE

SimplicityOS, a real x86_64 OS with a working Forth interpreter, was developed with Claude Code. Claude did all of the heavy lifting in the project, including writing all of the assembly code, debugging boot issues, managing git commits, and creating all of the documentation. The OS currently has a PS/2 keyboard driver with shift support, interactive REPL, colon definitions with nesting, variables, comments and strings, and introspection. The complete development narrative - every prompt, response, and struggle - is provided in the article.

isene.org7 min read

RUNNING UNSUPPORTED IOS ON DEPRECATED DEVICES

This dev successfully ran iOS 6 on an iPod touch 3, a device officially limited to iOS 5.1.1, by reverse engineering and modifying various iOS components. This involved patching the DeviceTree and iBoot, creating a kernelcache by adapting macOS tools, and making many changes to the root filesystem, including Bluetooth and Wi-Fi firmware adjustments.

nyansatan.github.io10 min read

02OPINIONS & ADVICE

RELEASING PACKAGES WITH A VALET KEY: NPM, PYPI, AND BEYOND

Publishing packages to registries requires access tokens. Whoever has these tokens can publish anything under that organization's name. This can be an issue if those tokens were stolen. One way to secure against this is to create a separate repository dedicated entirely to publishing. This limits write access while still allowing people to contribute.

byk.im10 min read

03LAUNCHES & TOOLS

A VERY FAST 64–BIT DATE ALGORITHM: 30–40% FASTER

This article presents a very fast date conversion algorithm that provides accurate results over a period of ±1.89 trillion years. The algorithm uses only 4 multiplications, compared to other fast date algorithms, which have always used 7 or more expensive computations. It calculates years backwards, which removes various intermediate steps. The algorithm uses a year-modulus-bit shift technique to calculate day-of-year, removing a division. It uses the 'Julian Map' technique to speed up 100/400 year calculation, removing two more hardware multiplications.

benjoffe.com15 min read

SAFE NPM

`safe-npm` is a security-focused npm installer that prevents supply chain attacks by only installing package versions that have been publicly available for a minimum time (default 90 days). It works by querying the npm registry, filtering out recent versions, and installing the newest safe version that meets semver and age requirements.

github.comGitHub repository

04MISCELLANEOUS

GEMINI CLI TIPS AND TRICKS

Gemini CLI is an open-source AI assistant that brings Google's Gemini model to the terminal. This is a guide of 30 pro tips for using Gemini CLI correctly that covers topics like persistent context, custom commands, extending functionality with MCP servers, memory management, checkpointing, file referencing, on-the-fly tool creation, system troubleshooting, automation, and IDE integration. The guide also describes how to use it with GitHub Actions and custom extensions.

github.com92 min read

WHY (SENIOR) ENGINEERS STRUGGLE TO BUILD AI AGENTS

A mind trained on strict interfaces will find the transition from deterministic systems to probabilistic agents uncomfortable because it requires trading certainty for semantic flexibility. The exact execution path can no longer be known or owned as the control flow has been handed to a non-deterministic model and application state is stored in natural language. Agents need to be managed through evals and self-correction because probability can't be coded away. Systems need to be engineered to be resilient enough to handle ambiguity.

philschmid.de6 min read