Hacker News: alcidesfonseca

Lessons Learned building an MCP proxy that acts as a behavioral firewall

alcidesfonseca — Mon, 19 Oct 2026 16:09:36 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/lessons-learned-building-fronteira/

Comments URL: https://news.ycombinator.com/item?id=50154153

Points: 2

# Comments: 0

New comment by alcidesfonseca in "CS240 AI Cheating Retrospective"

alcidesfonseca — Wed, 30 Sep 2026 23:13:27 +0000

I agree. Here at U. Lisbon, we are following the recommendation by the recent MIT report: Evaluate students by talking with them, making it a social interaction, which they are lacking.

We need students to work together and share their experiences. Then we need each one to achieve the learning goals (and we should not assess work they did far from our eyes. We should assess their understanding and skills in front of us).

Recommendations for Teaching with AI (Fall 2026)

alcidesfonseca — Sat, 12 Sep 2026 19:14:22 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/fall-2026-recommendations-for-ai-in-higher-education/

Comments URL: https://news.ycombinator.com/item?id=49676069

Points: 1

# Comments: 0

Deterministic behavioral (lethal-trifecta defeating) sandboxes with liquid types

alcidesfonseca — Wed, 19 Aug 2026 10:19:01 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/aeonbox-logical-guardrails-for-agents/

Comments URL: https://news.ycombinator.com/item?id=49359459

Points: 1

# Comments: 0

A new model for Source Control

alcidesfonseca — Fri, 07 Aug 2026 15:07:17 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/a-new-model-for-source-control/

Comments URL: https://news.ycombinator.com/item?id=49211607

Points: 1

# Comments: 0

New comment by alcidesfonseca in "Professor's invisible prompt trap catches 32/35 students cheating with AI"

alcidesfonseca — Mon, 27 Jul 2026 21:11:26 +0000

Professor here. Every single one of us that looks for it, finds plenty of examples of students “cheating”. Learning takes effort, and humans (some more than others) are designed to minimize effort.

We have designed education around exams and evaluation. If I design an exercise that does not contribute to their final grade, students don’t even look at it. If I design a 30min tutorial on a programming subject, students will not look at it and will spend 8 hours on the (graded) assignment that was designed for 1 hour on top of the 30 minute tutorial.

I am making some changes: evaluation will be as randomly as possible to minimize overfitting to our exercises. Draw from real world if possible.

I would also like to get rid of bologna’s modular structure and go to the UK’s one-exam-at-the-end-of-the-degree model.

But overall, we need more passionate students. Those don’t care about all this cheating and would appreciate that professors and future employers see their effort and success.

New comment by alcidesfonseca in "Why TUIs Are Back"

alcidesfonseca — Sun, 03 May 2026 22:45:35 +0000

Fixed both issues. Thanks!

New comment by alcidesfonseca in "Why TUIs are back"

alcidesfonseca — Sun, 03 May 2026 22:41:40 +0000

What popular desktop application is written in flutter?

Asking honestly, because none of the ones I use is.

Why TUIs are making a comeback

alcidesfonseca — Sat, 02 May 2026 10:16:28 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/why-tuis-are-back/

Comments URL: https://news.ycombinator.com/item?id=47985042

Points: 4

# Comments: 0

New comment by alcidesfonseca in "Show HN: Tusk for macOS and Gnome"

alcidesfonseca — Mon, 06 Apr 2026 22:56:16 +0000

Is it possible that the [x Telemetry] [x Electron] and [x Subscription] means that the app does not have those things?

New comment by alcidesfonseca in "Apple Business"

alcidesfonseca — Tue, 24 Mar 2026 17:20:17 +0000

The next neo might have the SSDs of the current pros, making swapping less problematic.

Why should operating systems and websites track the user age?

alcidesfonseca — Wed, 11 Mar 2026 10:55:38 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/age-verification-in-operating-systems-and-the-internet/

Comments URL: https://news.ycombinator.com/item?id=47333983

Points: 2

# Comments: 1

New comment by alcidesfonseca in "Bootstrap Bio (solves health at the genetic level/promotes eugenics)"

alcidesfonseca — Sat, 31 Jan 2026 08:53:06 +0000

I wonder about the ethical and legal implications of this work. We've all read and watched sci-fi that warn about the implications of doing this, but biologists agree that reducing diversity within a population makes it much more at risk.

Bootstrap Bio (solves health at the genetic level/promotes eugenics)

alcidesfonseca — Sat, 31 Jan 2026 08:53:06 +0000

Article URL: https://bootstrapbio.com

Comments URL: https://news.ycombinator.com/item?id=46834756

Points: 1

# Comments: 1

New comment by alcidesfonseca in "Typechecking is undecideable when 'type' is a type (1989) [pdf]"

alcidesfonseca — Sun, 23 Nov 2025 16:28:25 +0000

Liquid Types are more limited than "full dependent types" like Lean, Rocq, Agda or Idris. In Liquid Types you can refine your base types (Int, Bool), but you cannot refine all types. For instance, you cannot refine the function (a:Int | a > 0) -> {x:Int | x > a}. Functions are types, but are not refinable.

These restrictions make it possible to send the sub typing check to an SMT solver, and get the result in a reasonable amount of time.

New comment by alcidesfonseca in "Typechecking is undecideable when 'type' is a type (1989) [pdf]"

alcidesfonseca — Sun, 23 Nov 2025 16:25:43 +0000

I believe it to be historically true, but Dependent Haskell might change this (https://ghc.serokell.io/dh see unification of types and kinds).

In Lean (and I believe Rocq as well), the Type of Int is Type 0, the type of Type 0 is Type 1, and so on (called universes).

They all come from this restriction.

New comment by alcidesfonseca in "Racket v9.0"

alcidesfonseca — Sun, 23 Nov 2025 16:21:45 +0000

If it taught them the core concepts of writing good software, that's a win in my book.

Copyright, AI and the Future of the Web

alcidesfonseca — Wed, 12 Mar 2025 16:13:42 +0000

Article URL: https://wiki.alcidesfonseca.com/blog/on-copyright-and-ai/

Comments URL: https://news.ycombinator.com/item?id=43344770

Points: 2

# Comments: 0

New comment by alcidesfonseca in "M4 Mac mini's efficiency"

alcidesfonseca — Wed, 13 Nov 2024 08:30:07 +0000

Jobs would have kept the button on the bottom, as it's not the proper way to use a computer.

Instead, he would have put motion/light sensors on the screen, so it would automatically wake up when you are sitting in front of it. Macs don't shutdown, they just go to sleep and wake up when you need them.

New comment by alcidesfonseca in "Bend: a high-level language that runs on GPUs (via HVM2)"

alcidesfonseca — Sat, 18 May 2024 12:56:13 +0000

I think the (hidden) reasoning is that it is really easy to have speedups with slow interpreters. However, getting speedups in high-performance level programs is quite hard, mainly due to micro-optimisations.

That's where the comparison to Python comes from: getting speedup on slow interpreters is not very _relevant_. Now if your interpreter has the same optimisations as Python (or v8 or JVM), even a small fraction of what you show would be impressive.

Having said this, the work your team did is a really challenging engineering feat (and with lot more potential). But I do not believe the current speedups will hold if the interpreter/compilers have the level of optimisation that exist in other languages. And while you do not claim it, people expect that.