Upstream contributions.
Merged work in machine learning systems, database internals, and developer tooling. Mostly performance and correctness on Apple silicon and in distributed runtimes.
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MLX
11 mergedAdded
mx.searchsortedas a new public operation, implemented as a native primitive with hand-written CPU, Metal, and CUDA kernels. The binary search runs through the same comparatorsortuses, so ordering, including where NaNs land, stays consistent across all three backends. Also hardened multi-node distributed execution across both the ring and JACCL backends: a hang when a peer disconnects, an out-of-bounds read reachingibv_reg_mras a protection domain, an uninitialized GID handed to the queue pair, an errno dropped at the one point it was known, a ring transfer that could not carry a payload of 2 GiB or more, a malformed JACCL hostfile taken at face value, and a macOS SDK version compared as a string rather than a version. -
DuckDB
1 mergedFixed a hash join regression where dictionary emission changed a chain field from a pointer to an index, breaking the existing dead-end sentinel.
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mlx-lm
1 mergedServer fixes for running language models on MLX, including keeping
message.contentpresent on a non-streaming chat completion. -
Cloudflare workers-sdk
1 mergedFixed compound SQL statement parsing so a statement closes correctly when its terminating
ENDis lowercase. -
Apple password-manager-resources
1 mergedMade the converter reject character classes it cannot represent instead of silently emitting a rule that means something different.
llama.cpp
not yet mergedMade the RPC backend fail gracefully instead of aborting the whole process when a remote server goes away.
Core ML Tools
not yet mergedValidate a compiled model path before loading its structure or compute plan, so a bad path fails clearly rather than deeper in the stack.
3 open pull requests in flight across Core ML Tools, DuckDB, and llama.cpp.
Projects.
Systems and emulation
logisim-evolution rebuilt as a native Mac app in Swift. The clock keeps real time (3.6 µs drift, not 80 ms), checked byte for byte against 4.1.0 across 1,757 tests.
Built a fully playable version of Columns entirely in MIPS assembly. Implemented match detection, combo-based scoring, cascading gravity mechanics, real-time MIDI music, ghost piece preview, and difficulty scaling.
A full CHIP-8 VM in the browser, all 35 opcodes, 4KB memory, a live register/stack debugger, and playable ROMs like PONG.
Multi-process Monte Carlo engine in C: up to 16 workers, Unix pipe IPC, π estimation and bootstrap-based statistical inference.
Server-free collaborative drawing: a grow-only CRDT with Lamport clocks and tombstone undo that converges across tabs with zero coordination.
macOS and tooling
A native MCP server that lets AI agents drive Safari on macOS: navigate, click, type, run JS, screenshot, and capture console/network. Zero runtime deps.
Safari MCP's sister for native apps: lets AI agents screenshot, read and drive any macOS app, gated per app so nothing is visible until you grant it. Zero deps.
Turns the MacBook notch into a live control surface: activities, clipboard history, a file shelf, media controls, and conversion. SwiftUI and AppKit, no third-party deps.
Turns PDFs and videos into clean, chunked Markdown that preserves headings and section boundaries, so each chunk still means something on its own.
Browser and client-side
32 dependency-free browser demos, GPU fluid sims, ray tracers, physics, audio synths, emulators, all built from scratch and live on Cloudflare Pages.
Browser-based PDF suite with 12+ tools (merge, split, annotate, lock/unlock, compress, watermark, etc.). Zero server, all processing stays local.
Browser-based converter for images, video, audio, and documents, plus compress, background removal, and metadata tools. Zero upload, all processing stays local.
A faithful recreation of the popular word puzzle, guess the hidden 5-letter word in six tries, with instant feedback and a clean, responsive interface.
Real-time multiplayer Settlers of Catan: room codes, a procedural hex board, trading, dev cards, and victory-point tracking synced live across players.
Data and analysis
Interactive D3.js platform exploring 120+ years of Olympic competition: medal towers, venue maps, sport-specific metaphors, and narrative-driven design.
25 years of crude oil data: benchmark spreads, retail price pass-through, and 30+ annotated geopolitical events across WTI, Brent, WCS, Urals, and OPEC.
Relational betting platform with live data ingestion, probabilistic odds modelling, and a house-edge adjustment engine drawing from market making concepts.
Weighted collaboration graph from Spotify data: centrality metrics show eigenvector centrality beats raw collaboration count as an influence signal.
Every great developer you know got there by solving problemsPatrick McKenzie
they were unqualified to solve until they actually did it.