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davidcann

1,118 karma · joined April 17, 2008

david@davidcann.com

Buildermark https://buildermark.dev

Multitui https://multitui.com

Universymbols https://universymbols.com

Gelatinous Development Studio https://geldev.com

Previously, Co-founder of Double Robotics (YC S12) https://www.doublerobotics.com

submissionscomments
davidcann··on A way to exclude sensitive files issue still open for OpenAI Codex
You can block file access on macOS by running codex in a sandbox with my app: https://multitui.com
davidcann··on Apple's weird anti-nausea dots cured my car sickness
It works for me, but only if I hold the phone up in front of my face, basically perpendicular to the road.
davidcann··on Automating myself out of development
Thanks for the report. I messed up the CDN settings. It looks fixed now.
davidcann··on Automating myself out of development
I built this with 94% written by coding agents: https://buildermark.dev/

The complete log of all prompts and commits is here: https://demo.buildermark.dev/projects/u020uhEFtuWwPei6z6nbN

davidcann··on Ask HN: Why is the HN crowd so anti-AI?
Photoshop alternatives already exist and are cheap or free, like Affinity.

Why create a Final Cut Pro alternative when it’s so cheap from Apple?

Many existing apps can be mostly cloned by a small team over 6 months or a year, but the challenge is finding customers willing to switch. You still need to add something new and useful, then reach customers somehow.

davidcann··on Strace-ui, Bonsai_term, and the TUI renaissance
You can also sandbox TUIs, with full control of the sandbox parameters. To do this on macOS, you can use: https://multitui.com
davidcann··on Ask HN: What are you working on? (May 2026)
Buildermark calculates how much of your code is written by agents. Open source, local, and cross-platform (written in Go).

https://buildermark.dev

davidcann··on Uber torches 2026 AI budget on Claude Code in four months
> 70% of committed code originating from AI.

How are they calculating that? They could be using my tool, Buildermark, but I do t think they are: https://buildermark.dev

davidcann··on Google plans to invest up to $40B in Anthropic
Thanks for the feedback. I agree that it’s changing very fast, which is why my thesis is that this tooling will be needed to help everyone on the team keep up.
davidcann··on Google plans to invest up to $40B in Anthropic
Is your team measuring how much of your code is being written with claude and comparing amongst the team, like what works best in your codebase? How are you learning from each other?

I’m making a team version of my buildermark.dev open source project and trying to learn about how teams would like to use it.

davidcann··on Claude Code to be removed from Anthropic's Pro plan?
To help you decide if you should keep your Claude subscription, you can see how much of your code is written by Claude Code with my project (open source, local): https://github.com/gelatinousdevelopment/buildermark
davidcann··on Ask HN: What Are You Working On? (April 2026)
I’m working on Buildermark (open source, local) that calculates how much of your code is written with coding agents.

It scans your claude and codex history to find edits and matches those to git commits (even if the code was auto-formatted).

https://buildermark.dev/

You can browse all 364 prompts that wrote 94% of the code here:

https://demo.buildermark.dev/projects/u020uhEFtuWwPei6z6nbN

davidcann··on Ask HN: What Are You Working On? (March 2026)
Native macOS sandbox terminal:

- UI for sandbox-exec to protect filesystem - Network sandbox per domain - Secrets filter via gitleaks - Vertical tabs option

It's highly customizable. You generate native macOS app wrappers for each terminal app, each with its own rules and customizations.

https://multitui.com

davidcann··on Agent Safehouse – macOS-native sandboxing for local agents
I made a native macOS app with a GUI for sandbox-exec, plus a network sandbox with per-domain filtering and secrets detection: https://multitui.com/
davidcann··on macOS's Little-Known Command-Line Sandboxing Tool (2025)
No, I run a separate URL detection to make links clickable. However, SwiftTerm just added link detection a few days ago and I haven’t had time to look into theirs yet.
davidcann··on Let's discuss sandbox isolation
My app is a macOS terminal wrapper with nice GUI for sandbox-exec and network sandbox. I just added a vertical tabs option too. https://multitui.com
davidcann··on macOS's Little-Known Command-Line Sandboxing Tool (2025)
Yeah, that’s understandable. Many open source macOS-only apps seem to get abandoned, so I’m trying to build something sustainable.

It uses only 3 dependencies that are very well known and widely used, so supply chain risk is minimal. That leaves me, the developer, as the main point of trust.

davidcann··on macOS's Little-Known Command-Line Sandboxing Tool (2025)
SwiftTerm, for not. I may switch to ghostty when their library is ready for embedding.
davidcann··on macOS's Little-Known Command-Line Sandboxing Tool (2025)
Yeah, they all do sometimes, but the agent decides what to allow and they can choose to not use it. This gives the user full control of the sandbox and you can run the agent in yolo mode.
davidcann··on macOS's Little-Known Command-Line Sandboxing Tool (2025)
I made a UI for this to run terminal apps, like claude and codex: https://multitui.com
davidcann··on Show HN: Multitui – sandbox claude/codex/gemini on macOS without containers
The same concept is possible on Linux, but I don't think anyone has created a nice UI for it yet. There was a post yesterday about doing it on the command line in linux: https://news.ycombinator.com/item?id=46874139

One of the nice things in Multitui is that it monitors what is blocked and gives you a way to add a read/write rule from the UI.

davidcann··on Bunny Database
I’m seeing log delays too the past couple of days… something like 14 hours, in my case.
davidcann··on Sandboxing AI Agents in Linux
My app does this on macOS! https://multitui.com
davidcann··on Show HN: Multitui – sandbox claude, codex, or any TUI with custom macOS apps
Thanks! For network sandboxing, I was thinking something like what Little Snitch can do, but more customized... maybe block POST requests and long GET request strings or anything that looks like too much code or secrets.
davidcann··on The Codex App
Shameless plug, but you can sandbox codex cli without a container using my macOS app: https://multitui.com
davidcann··on Iconify: Library of Open Source Icons
My site can extend a bunch of the icon sets that are on Iconify with AI image models, so you can feel comfortable using a more unique set than just the big ones: https://universymbols.com
davidcann··on Ask HN: Those making $500/month on side projects in 2025 – Show and tell
I make https://universymbols.com and it’s still new, but off to a good start. It can create/restyle feature icons to expand an app’s icon set.

It supports SF Symbols, Material Symbols, and a bunch of open source styles, but I’m adding the ability to make a private custom style target.

davidcann··on Ask HN: What Are You Working On? (December 2025)
I’m working on Universymbols, which lets you restyle icons to match your app’s icon set, like SF Symbols, Material Symbols, and many more.

It uses a pipeline involving several AI models, including Nano Banana and OpenAI’s gpt-image-1 for the raw image generation.

https://universymbols.com/

davidcann··on Ask HN: Who is hiring? (April 2014)
Double Robotics - Sunnyvale, CA

Come build products that change the future of remote human interaction. We are leading the new wave of consumer robotics and we need your help to take it to the next level.

  * Full Stack Web Developer (node.js/python/js/php)
  * iOS Developer
  * Embedded Firmware Developer
  * Electrical Engineer
Email jobs@doublerobotics.com with examples of your work.

http://www.doublerobotics.com/jobs.html

davidcann··on Rtc.io – Open source WebRTC library
Chrome on iOS does not. Chrome on some Android devices does.
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