Show HN: Specification First Agentic Development Plugin and Prove
Posted by hleichsenring 6 hours ago
Implemented agent smith since start 2026 with over 1000 specifications which lead to about 500k lines of code. The procedure with that spec-first works well. How do you do it?
Comments
Comment by _ink_ 17 seconds ago
Comment by memjay 1 hour ago
Some day we won't even need coders any more. We'll be able to just write the specification and the program will write itself.
Oh wow, you're right! We'll be able to write a comprehensive and precise spec and bam, we won't need programmers any more!
Exactly!
And do you know the industry term for a project specification that is comprehensive and precise enough to generate a program?
Code It's called code.
Comment by _davidwarner 31 minutes ago
So the main challenge I see with this approach is getting the spec right. Too little detail and the output is uncontrolled, too much detail and you're adding too many constraints (and you may be better off just writing code). From my experience, agents haven't been the best at writing good specs. But maybe this project can help with that?
Comment by hleichsenring 1 hour ago
After 500k lines of code in Agent Smith, none of which I wrote by hand, I have to admit it: coding is more or less solved. That doesn't mean architects, developers, DevOps people and everyone else aren't needed anymore. I think they're needed more than ever.
Just implementing something isn't good enough. The spec has to point to sensible approaches and procedures, and the code has to be well structured (in my view, at least). Then the specs can simply run in parallel all night.
So my actual work on Agent Smith isn't coding at all. It's deciding what the right thing to build is, and how, in terms of design and architecture. I don't even review the code. But I do test it: 10k tests, a harness, a commit hook that blocks a spec while the suite is red, the whole story.
And unfortunately, that works pretty well. I also think last year's programming was more romantic :-D
Comment by geraneum 7 minutes ago
Why unfortunately?
Comment by Paracompact 1 hour ago
Do you know why it's easier to specify theorems than it is their proofs? Or why ACSL != C?
You can go ahead and make a more specific argument, e.g. that mainstream UX-centric software development may not be amenable to current paradigms of formal verification, but to insinuate that a complete spec reduces to source code itself is naive.
EDIT: Possibly I have responded too acutely to the points you care less about. I agree that "in the future we won't need programmers" is questionable since good spec-writing and spec-vetting requires at least as much expertise, if not more, than ordinary coding work, and that is fair to call comprehensive spec work "code" in that it is technical and formal. But it is decisively not source code.
Comment by avlman 38 minutes ago
Comment by cassianoleal 4 hours ago
Comment by hleichsenring 1 hour ago
Comment by systima 37 minutes ago
Comment by woeirua 3 hours ago
What does work well is using AI to generate a quick and dirty prototype ala vibecoding, and then using that as a basis to regenerate the final code. Some might say it's still spec driven development, but the spec is a working prototype.
Comment by hleichsenring 1 hour ago
Comment by drdexebtjl 39 minutes ago
We’ve been using SDD at $workplace for more than a year and we’ve started to actively remove all spec documents so agents don’t get stuck reviewing out of date context for 20 minutes, burn through token budgets, and give disproportionate focus on legacy patterns and business directions we’ve pivoted from.
Models are RLHF’d to work on non-historical documentation and iterative design, and that’s what yields the best overall results.
Comment by TimmyatLoadout 1 hour ago
Comment by meMohamedAtef 2 hours ago