Dennis Hernández 💙

Engineer, Owner of DinoTech, AI advisor, Husband, Father of two

[Miguel de Icaza ᯅ🍉 @migueldeicaza]

@davidcrawshaw I am confused what does this do? I just started using https://t.co/Uan7dcMSpY and it is magical, but I am a noob

[Addy Osmani @addyosmani]

https://t.co/2gyp2Erpxx

[Dennis Hernández 💙 @djhvs]

@trq212 I'm super happy about this moment. I'm in my prime

[Dennis Hernández 💙 @djhvs]

@CFDevelop 153

[ClaudeDevs @ClaudeDevs]

https://t.co/sRyO7OigQ7 is our new home for developers building with Claude.

You'll find engineering deep dives, Claude Code and API guides, tips from the teams building Claude, and some fun easter eggs.

[Vox @Voxyz_ai]

Claude Code tip: before you ship, have Opus 5.5 send out 𝟰 𝘀𝘂𝗯𝗮𝗴𝗲𝗻𝘁𝘀 whose only job is to break your app, and split 𝘁𝗵𝗲𝘀𝗲 𝟭𝟲 𝗾𝘂𝗲𝘀𝘁𝗶𝗼𝗻𝘀 between them:

Security
→ Do your bundled frontend JS or git history contain private keys like sk_ or service_role?
→ Skip the UI and call your APIs directly, logged out or with someone else's ID. Does the server stop you?
→ Change the price, quantity or role in a request and send it again. Does the server accept it?
→ Hit the same endpoint 100 times in a row. Is there a rate limit per user and IP?
→ Hide a snippet that pops an alert in Markdown, rich text or an uploaded SVG. Does it run when another account opens it?

Data
→ Load 10,000 records. Does the page still open?
→ Use a 200-character name with emoji. Does it break the layout?
→ Sign up with the same email in different capitalization. Did you just get two accounts?
→ Submit an empty form. Is there now a blank record in your database?

Flows
→ Place the same order twice at once, and replay the same payment webhook twice. Did you get two orders?
→ Refresh or hit Back halfway through a form. Is what you typed still there?
→ Save while offline: it says saved, but nothing was stored
→ Upload a 50MB image. Does everything freeze?

Environment
→ On a small phone screen at 200% zoom, can you still tap every button?
→ Switch to Safari's engine. Does the layout fall apart?
→ For users in other time zones, are dates, deadlines and check-ins off by a day?

Set all 4 subagents to high effort. The security one covers payments and login, where one mistake is a disaster, so you can raise it to xhigh or even max. Anthropic's Thariq has said that turning effort up mostly buys more verification and edge-case testing.

Send this whole post to Claude Code, and add this line at the end 👇
"Create 4 testing subagents in ~/.claude/agents, one for each group above: security-breaker, data-breaker, flow-breaker and env-breaker. Use model opus for all of them, effort high, and xhigh for security-breaker. Give them permission only to read files, run commands and use a browser (Playwright), with no changes to code or config. Install Playwright first if it's missing.
Before every launch, run the app locally or in a test environment and have each of them work through its group item by item. If login is needed, ask me for two test accounts first. Use payment test mode only. Mock the AI APIs, or use a test key with a spending cap. Write test data only to a test database and clean it up afterwards. If you find production keys or a live domain, stop immediately and ask me.
For every issue, write the steps to reproduce, a screenshot and the fix. Combine them, rank them by severity and hand them to the main session to fix. Mark anything you can't test as "untested" with the reason. Show me the files you'll create first, and don't write them until I confirm."

[DHH @dhh]

Agent-led development asks you to have a business-owner mindset: What's the outcome we're trying to achieve? The less you're required the dig into the details, the easier it is to see the big picture.

[Dennis Hernández 💙 @djhvs]

@dhh Love the message! Tbh I didn't know you before that masterpiece talk.. now that I have been watching multiple videos and post from you.. I feel supported, excited for the future and as a father more engaged to show my two boys all AI wonderful! Love to take them into this journey

[DHH @dhh]

The constant decel messaging in Europe is insufferable as an adult, but its effect on kids is worse. As a parent, it's your obligation to counterprogram this nonsense. Show them robots, rockets, and wonders of AI. Show them cathedrals and moon landings. Instill hope in progress.

[Thariq @trq212]

If you want to see interactive explainers of benchmarks and demos I built, you can read it on our new dev site here: https://t.co/oSTZrBggXM

[Thariq @trq212]

What is effort really? When do you change it it and why not just use max effort for everything?

I dove deep into this problem, looking into evals and doing my own tests and I was quite surprised by the results. https://t.co/KO2D51j34H

[Hatake @rhatake_jp]

Opus 5.5 の公式ガイド合わせて設定見直したらだいぶトークン効率よくなったな〜上限あまり気にしなくてよくなった
https://t.co/sDNqjBj09r

[Milan Jovanović @mjovanovictech]

"Writing code by hand is no longer an economically productive enterprise for the vast majority of programmers working at the vast majority of companies. That's today."

@dhh wasn't holding back. I think every developer should listen to this keynote.

https://t.co/4tRF5IBNDP

[Peter Steinberger @steipete]

Huh. There is a catch. https://t.co/fFVtXq8frn

[DHH @dhh]

It's pencils down, people. Writing code by hand is no longer an economically viable skill for most programmers at most companies. But the future of making software has never been brighter. Don't you dare black pill this beautiful moment! https://t.co/qaCgfmkW0u

[Sasa @lady_sasa_cr]

Dejen de inventar historias. El mae andaba la licencia vencida y, en Estados Unidos, las cosas no funcionan como en Tiquicia, donde si usted anda sin la licencia al día le da 20 rojos al oficial de tránsito y listo. ¡No! Allá son sumamente rígidos con el cumplimiento de la ley.

[Uncle Bob Martin @unclebobmartin]

Given that agents still need high level supervision. And given that the human review of code is a bottleneck. And given that the models have gotten good enough that strict deterministic harnesses are suboptimal.

Then how should we supervise their output.

My current solution is to use an interrogation tool coupled with an agent. The tool displays the structure of the system in a UML-like diagram, color coded with crap and mutation scores. The diagram is dynamic, allowing the user to click on element and drill down through the architecture -- all the way to code.

The user can detect structures that need improvement and tell the associated agent to make the appropriate changes. These changes can range from high level architectural changes, to the lowest level code refactorings. The associated agent will make those changes and cause them to be redisplayed.

The tool I'm using is custom made for me, but you can point an agent at it and use it as a template to build your own custom tool.

It's a work in progress, so don't be surprised if it changes a lot over the next few weeks. But then you probably won't care because by then you'll be deep in customizing it for yourself. And anyway, you can always point an agent back at mine, or someone else's, and integrate improvements into your own.

https://t.co/tu0Dsc9Vta.

[Uncle Bob Martin @unclebobmartin]

General rule of thumb for success.

Don't be afraid to try things! Especially things that everyone else dismisses.

You know, like electric cars, reusable rockets, solar power, self-driving cars, UML.

[Dennis Hernández 💙 @djhvs]

@melvindvivas Moving to codex then

[Ethan Caballero @ethanCaballero]

anthropic released a new prompt that eliminates claudese:
https://t.co/JYHotoZlyr