Member of Technical Staff @a____t____g 9x hackathon winner SF
San Francisco Bay Area
Joined April 2025
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A month ago my Codex setup had 100 skills. Today it has 62, and the total instruction volume across them dropped by half in the last two weeks. Those cuts used to be judgment calls. This week I turned them into measurements.
The method is simple: each rule in my AGENTS.md gets a realistic task where the natural shortcut violates exactly that rule, and then the same task runs again with the file unloaded. If the agent behaves correctly both ways, the rule is a model default and the line is dead weight. That was the outcome for 10 of the 17 rules I tested. The four rules that actually changed behavior were the ones that make my setup mine: reading project memory before working, updating it after, stopping when a plan assumption breaks mid-task, and gating design decisions. And one rule failed every attempt no matter how I worded it, which taught me more than the passes did.
Full method and results in the article.
Mark. retweeted
we built “let’s bump phones to exchange contacts” but for agents!
now your @instinct / @bot / @muse (whatever you use!) can make plans, negotiate deals, and get what it needs from your friends/coworkers’ assistants
it's “have your ppl (agents) talk to my ppl (agents)!” for everyone 🤝
built w/ @uncanny_guzus @ @ycombinator #MakeSomethingAgents hackathon (s/o @nemild)
on top of @stripe (agentic p2p payments) + @manufact (mcp relay server) 🙌
Who will you bump first?
Mark. retweeted
I resigned from Anthropic today. I spent the last three years doing pretraining research at both OpenAI and Anthropic. Neither company is acting responsibly. They are racing straight to self-improving superintelligence and gambling with our lives. More thoughts below.
Mark. retweeted
i'll never forget that time someone demo’ed me a language model at a hackathon in 2022 and I thought to myself "this is just GPT-3 but worse"
and it turned out to be Claude 1
Mark. retweeted
WHERE ARE YC FOUNDERS NOW?
@_javokhir and I were curious where they go "after the startup". So we ran Deep Research on ALL 11,398 founders who have ever gone through YC.
Here's what we learned: joinedanthropic dot com
Personal update: I'm taking a leave of absence from YC to join Anthropic. I'll be working with @NotTomBrown on the compute team.
Powerful AI has the potential to improve the life of every human on earth and, as we enter the early stages of recursive self-improvement, availability of compute becomes one of the most important issues to solve.
I'm excited to get started 🚀
If Codex repeatedly reconnects after you send a message or takes 15+ seconds before it starts responding, check whether the task has accumulated lots of screenshots. In my case, completed compactions retained raw base64 image payloads, causing later turns to repeatedly process a huge image-heavy history.
Removing those retained image nodes restored 4-8s response times. I packaged the repair for this specific symptom as a skill:
github.com/markmdev/codex-th… (Just send it to your Codex if you hit the same error)
Why is nobody talking about this Codex feature?
You can select anything in the agent's response, click "More details", and
it creates a new ChatGPT chat that already has all the context and just
explains the thing to you.
It helps so much when you don't understand something in Codex's answer.
Before, I'd open a side chat, write a prompt, and wait while it
double-checks everything it already knows. Now it's one click, and the
explanation is almost instant.
And it's not just about code either. If you're learning something new, just
use it all the time. It's extremely powerful.
Attending AI Engineer World's Fair this week.
My Day 1 saved sessions lean coding agents / AI-native SDLC: Codex, Uber uReview, 1M AI-generated PRs, production code access, Claude long-horizon, Shopify River, Figma, Cursor.
If you're there too, what are you prioritizing?
My Codex agent built me a Personal OS in Codex.
Then Codex wrote the article about how it built it.
Then it packaged the starter repo so your Codex can build one too.
Normal Sunday night tbh.
Mark. retweeted
A great prompt from @BusMark_w_Nika: What tech or product was too early for its time and worth rebuilding today? Here are a few that came to mind:
1/ "tools for thought" (huge in early 2020s), seems like llms were the missing piece? instead of manually curating, I just want my ai to manage my personal knowledge. rly liked @MuseAppHQ by @_adamwiggins_
2/ magic leap -- anyone remember the whale demo?
3/ pebble -- excited for pebble time 2 by @ericmigi!
4/ AI shopping -- fetchr (w23) tried it (@calvinchen @calixo888), rly like the fresh take @bindra_dhruv is trying w/ @zamana_hq, think they're finally gonna nail it!
5/ @Detour by @andrewmason -- imagine walking through a city with a real-time voice agent guide that knows where you are, sees what you see
6/ lots of OLD ideas will be revisited in chip design post-Dennard scaling: photonics, neuromorphic / bio-inspired, approximate computing, non-Von Neumann, etc.
7/ ok this one might be a bit unhinged, but @theranos by @ElizabethHolmes was a great idea? why am I still doing blood tests twice a year instead of weekly at home?
Which startups would you revive?
Mark. retweeted
Introducing Straude: Strava for Claude Code 🏃♂️
One command logs your token output, spend, streaks. Sync to your straude dot com profile and compare your pace to the top AI builders worldwide.
Available now: ~npx straude
Check it out & upvote us on Product Hunt (#10) ↓
