Opening

gridcraft, a pure-Rust spreadsheet that shot to 7.1k★ in 30 days, and the best part isn't the GUI, it's the bundled headless CLI and MCP server: finally an .xlsx engine that agents and CI can actually drive. The same team also shipped cadcraft at 7.5k★, a clean-room rewrite of an AutoCAD-style drafting tool. On top of that, there's a book discovery site that pulled 1,826 points on HN, with a dataset that's borderline absurd in scale. I'll explain in a moment how it tells "mentioned" apart from "recommended." I'm Muyan, and this is the Open Source Daily.

Today's Picks

1. gridcraft: A pure-Rust spreadsheet engine that CLIs and AI agents can drive

• What it is: A spreadsheet app written from scratch in Rust, Apache-2.0 licensed. The pain point is very concrete: if you wanted to batch-process .xlsx files in CI, you either hand-rolled formula logic with a library like openpyxl, or spun up a machine with Excel installed and drove it over COM. gridcraft ships a full calculation engine plus a headless CLI, aimed squarely at people who need to automate Excel files without opening a window.
• Recent traction: 7,071 ★ on GitHub, a project that blew up within 30 days.
• Highlights:
  • gridcraft-cli eval '=SUM(1,2,3)' evaluates formulas straight from the terminal; to modify a file, use gridcraft-cli run --in book.xlsx --cmd 'home.bold={"range":"A1:C1"}' --out book.xlsx, so the whole pipeline is scriptable.
  • Built-in MCP server: a single claude mcp add gridcraft -- gridcraft-cli mcp lets an AI agent operate workbooks directly, and there's a JSON control channel too.
  • The CLI's calc oracle (check) is clever: Excel caches each formula's result next to the formula when saving, so gridcraft recomputes and compares cell by cell: numbers within --tolerance, errors by error type, text and booleans matched exactly. It's essentially a built-in regression test suite.
  • The same Rust codebase runs on desktop (macOS / Windows / Linux / BSD) and in the browser via WASM; .xls (BIFF8) import covers values, formulas, number formats, merged cells, column widths and row heights, and defined names.
• Getting started: On Linux the fastest route is sudo snap install gridcraft (the headless tool is called gridcraft.cli), with .deb / .rpm packages also available. To build from source, run cargo run --release -p gridcraft -- --sample sales, which requires Rust 1.95 or later.
• Caveats up front: The README labels it pre-alpha. It covers roughly 89% of Excel's ribbon/menu commands and about 93% of worksheet functions, but by depth-weighted estimate only about 65% of what heavy Excel users actually need. Fine for automation tasks; do not bet on it replacing the finance department's monster workbook at this stage.
• Compared to alternatives: LibreOffice Calc has its own UI and macro system, whereas gridcraft deliberately reuses Excel's ribbon command IDs (home.bold, insert.chart), so your muscle memory carries over. Compared to openpyxl / pandas, it isn't a library but a full app with a complete calculation engine, and it plugs straight into agents as an MCP server.
• Who it's for: Engineers who need to read, write, and recalculate .xlsx inside CI or agent workflows without touching Autodesk-style or Excel licensing.
• Link: https://github.com/storytold/gridcraft

2. cadcraft: A clean-room rewrite of an AutoCAD-style 2D drafting tool

• What it is: Another hard problem tackled by the same team (storytold): a pure-Rust, clean-room AutoCAD-style drafting tool, Apache-2.0. The pain point is even blunter: you just want to open a DXF/DWG, tweak a couple of entities, and batch-convert files, yet you're stuck paying for an Autodesk subscription. The backstory is good too: the README says most of it was written by AI coding agents over a few weeks.
• Recent traction: 7,517 ★ on GitHub, also a project launched within the last 30 days.
• Highlights:
  • Native DXF read/write (ASCII and binary, R12 through 2018); DWG (R13 through 2018) open/save goes through the open source acadrust library.
  • Preserves AutoCAD muscle memory: command line, object snaps, layers, dimensions, hatch patterns, blocks, and layout plotting.
  • The same automation trio as gridcraft: MCP server, JSON control channel, plus cadcraft-cli (info, convert, run, commands, mcp), so agents can draw or batch-convert directly.
  • Cross-platform across macOS / Windows / Linux / FreeBSD, and it compiles to WebAssembly to run in the browser.
• Getting started: If you don't want to install anything, try the browser build at cadcraft.org/online first. Locally: git clone https://github.com/storytold/cadcraft && cd cadcraft && cargo run --release -p cadcraft -- --sample (requires Rust 1.95+), or grab the .deb / .rpm from releases.
• Caveats up front: The README states plainly that it's in early development, and there's an admirably honest section on file-format parity: entities CADCraft hasn't modeled yet are not preserved on save. In other words, round-tripping someone else's DWG can silently drop data, so back up important drawings and don't overwrite in place. It also explicitly states it has no affiliation with Autodesk.
• Compared to alternatives: Versus established open source 2D CAD like LibreCAD and QCAD, cadcraft is pure Rust with GPU rendering, native DWG support (via acadrust), and MCP/CLI automation; it's licensed MIT OR Apache-2.0, unlike QCAD, which locks some features behind the Professional paywall.
• Who it's for: Engineers who occasionally need to open DXF/DWG files or automate batch conversions, without carrying an Autodesk subscription for it.
• Link: https://github.com/storytold/cadcraft

3. HackerBooks: Compressing 2007-2026 HN comments into a sortable book index

• What it is: The books equivalent of Karpathy's HackerTube. The pain point: "I know tons of great books get recommended on HN, but those discussions are buried across a decade-plus of comment threads." It turns the whole corpus into a sortable, downloadable index you can use immediately, no account required.
• Recent traction: 1,826 points and 302 comments on Hacker News, the week's biggest hit.
• Highlights:
  • The scale is serious: HN comments from 2007 through 2026, covering 15,766 books, 281,363 mentions, 225,861 comments, and 57,773 distinct commenters.
  • It deliberately separates "mentioned" from "recommended": rankings are based on the number of distinct commenters, which prevents one person from repeatedly boosting the same book and keeps widely panned books off the top. This design choice is the single most worth-stealing idea on the site.
  • The build pipeline is documented clearly: HN public dataset → regex plus lightweight NLP to extract candidates → match against Open Library for stable IDs, authors, first publication year, covers, and subjects → full-corpus rescan for counts → small language models used only for ambiguous titles like Dune, Influence, and Range.
  • Every book links back to the original comments that mentioned it, and the dataset is downloadable straight from the about page.
• Getting started: Just open hackerbooks.org. The homepage reshuffles a fresh batch of books daily; you can switch to the all-time ranking or browse by category (Programming 1,279 books, Software Engineering 328, and so on). If you want to run your own analysis, grab the dataset from the about page.
• Compared to alternatives: Unlike Goodreads/Amazon algorithmic recommendations, its signal comes 100% from HN community comments. Compared to searching HN yourself, it compresses a decade-plus of scattered discussion into a single sortable, downloadable index.
• Who it's for: Anyone looking for books that engineers actually recommend, or wanting a clean corpus for data analysis.
• Link: https://hackerbooks.org

Closing

There's a common thread across today's three picks: gridcraft and cadcraft are both doing the same thing, carving CLIs and MCP servers out of heavyweight desktop software that used to be GUI-only, so agents and CI can drive them directly. That's probably going to be table stakes for desktop tools over the next year or two. If I had to pick one to install first, I'd go with gridcraft, because "evaluating Excel formulas in CI" is such a common pain point and a single snap command gets you there. But both are still early: fine for automation, just keep backups of anything important. I'm Muyan, this has been the Open Source Daily, see you tomorrow.