Simon Willison — Week of 2026-04-18 to 2026-05-01#

Highlight of the Week#

The alpha release of llm 0.32a0 marks a foundational architectural pivot for Simon’s ecosystem of CLI tools. By moving away from a simple text-in/text-out abstraction to one that natively models complex message sequences and typed streams, the library is now future-proofed to handle the realities of modern frontier models. This opens the door for seamless integration of server-side tool calls, multi-modal inputs, and reasoning tokens.

Simon Willison — 2026-04-27#

Highlight#

The most substantive post for developers today is Simon’s hands-on experiment running Microsoft’s VibeVoice model locally via MLX. It’s a great example of his signature workflow: taking a newly accessible open-source AI model and immediately figuring out the most frictionless CLI one-liner to get it running on Apple Silicon.

Posts#

[microsoft/VibeVoice] · Source Simon explores Microsoft’s MIT-licensed VibeVoice, a Whisper-style speech-to-text model that notably includes built-in speaker diarization. He shares a practical one-liner using uv and mlx-audio to run a 4-bit quantized version locally on a Mac. Testing it against a one-hour podcast interview, it transcribed the audio in under 9 minutes and impressively distinguished between the host’s conversational voice and his “sponsor read” voice. You’ll need to manually split audio files longer than an hour to avoid token limits, but the resulting JSON drops nicely into Datasette Lite for browsing.