Simon Willison’s Weblog
I was working on a project from my phone using Codex Remote when I found myself wanting to edit a credentials file without round-tripping those credentials through the LLM itself.
So... I had Codex and GPT-6 Astra Extra High build this Python web app which provides a web UI for viewing and editing files in a folder. It's intended to be run over Tailscale, so I can have an agent start this running and then edit files via my Tailscale network directly from my phone.
Here's the interface for browsing files in a folder:
Editing uses CodeMirror 6 - I was going to use Monaco but that still doesn't have a great mobile experience yet.
Recent articles
Hello Python 3.15, goodbye 3.10, and now I can use 3.11 - 12th October 2026
A new feature for my blog, built using my voice - 9th October 2026
Claude Haiku 5.5 - 7th October 2026
We're going to need default hard budget caps on pretty much everything - 3rd October 2026
This is a beat by Simon Willison, posted on 12th October 2026 .
Monthly briefing
Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.