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Disagree. I operate this way inside a multi-million line legacy codebase.
by extr 1mo ago
Disagree. I operate this way inside a multi-million line legacy codebase.
- nujabe 1mo ago> I work at a small startup How does a “small startup” end up with a multi million line “legacy” codebase? Something not mathing
- extr 1mo agoHave you worked at many startups?
- nujabe 1mo agoNo, but not relevant. What is the point of working at a startup if you’re dealing with millions of lines of legacy code ? Isn’t the whole point of startups to create & innovate with a clean slate and modern tools?
- extr 1mo agoNo, actually. The point is to build a profitable business.
- sarchertech 1mo agoHow long has your startup been around? I’ve worked at plenty of startups over the past 20 years. Including one that was still calling themselves a startup 10 years out. The org I work at now was a startup before my tech giant employer acquired them. We have a very bloated and very profitable 8 year old codebase that is barely 500k LOC. I’ve never seen a startup with a multi million line legacy codebase.
- dgellow 1mo agoThey may have forked something
- sarchertech 1mo agoDefinitely possible, but up thread they wrote: >”Have you worked at many startups?” In response to a question about a legacy codebase at a startup. That implies that they think whatever they are doing is common. And forking a multi million line codebase and heavily developing it isn’t common for startups.
- dgellow 1mo agoYou’re right, very confusing thread
- fatata123 1mo ago[dead]
- chris_money202 1mo agoI don't know if that's the whole point, but I agree with the sentiment, why would a startup be working in legacy code and where would that code come from if this is truly the start of something. OP might just be working at a small software company or for one that broke from a bigger one and is now "startup" like?
- Karrot_Kream 1mo agoSomething isn't clear about the size of your codebase here and the level of reliability your customers expect, as a reader of your comments. Clarity there will help. My observation has been: - Initial greenfield work by an LLM is fast and very effective with minimal or no human oversight. - Subsequent work ends up being over engineered and very verbose. Assumptions are made that aren't suited to the problem at hand (for example I find Fable is extremely regex happy where structured data would work much better from a readability perspective.) - Once code bloats beyond a certain point due to unguided LLM usage, complexity is high enough that only LLMs can operate on the codebase with any economical amount of time. - Rinse repeat and your code ends up unclear about any state that's not explicitly being tested and verified in QA loops For some of our products this has been fine, for others it's been problematic. An understanding of your size and reliability requirements will help make the conversation more productive.
- extr 1mo ago> unguided LLM usage Why aren't you guiding your LLM usage? Is that what I said - to spam it and not guide anything? Or to have a careful workflow where you agree on design and maximize your human judgement/leverage? > any state that's not explicitly being tested and verified in QA loops As opposed to before, when engineers perfectly reasoned about code behavior from first principals and QA was unnecessary?
- Karrot_Kream 1mo ago> Why aren't you guiding your LLM usage? Is that what I said - to spam it and not guide anything? Or to have a careful workflow where you agree on design and maximize your human judgement/leverage? You didn't say anything positively or negatively regarding this so I made an assumption that you were using the LLM relatively unguided (e.g. a bit of oversight, not the kind of thing that heavy code reviews used to involve pre-agents.) Feel free to add clarity on your actual usage loop. > As opposed to before, when engineers perfectly reasoned about code behavior from first principals and QA was unnecessary? In my experience, most engineers are quite good at reasoning about code behavior for non-QAed code paths. Obviously things fall through the cracks. But I've been in the ground floor of plenty of Big Techs in their early stages before agents and, yes, a lot of initial development had spotty test coverage and yet most of the engineers had good mental models of what was happening. It used to be a very valuable skill to wrap your head around a torrid piece of code with few or no tests but was nonetheless a core piece of your application. Conversely, agentic development can bring cognitive debt [1]. === This isn't a fight. We aren't sparring over what's right and wrong. I'm just curious how other people use agents in their work as someone who is also now in a startup that uses LLM agents heavily and has no limitations on spend. [1]: https://martinfowler.com/fragments/2026-02-09.html https://martinfowler.com/fragments/2026-02-09.html
- darkwater 1mo ago> How does a “small startup” end up with a multi million line “legacy” codebase? Easy! The output of 6 months ago Opus! Which seemed so wonderful at the time.
- champagnepapi 1mo agoThis! I don't think folks understand how easy it is to go from greenfield to brownfield with these tools, esp if your organization is only valuing velocity. Meaning your doing full agentic development on large features, barely reviewing any code, and shipping without much refinement. It's insane, but this appears to be the status quo in SF startups.
- icedchai 1mo agoYou'd be surprised. I met a guy last week who was proud to tell me he had vibe coded an almost 2 million line code base. The app did not sound that complicated, so I'm assuming it's full of copy-pasta flavored slop.
- lilbigdoot 1mo agoMeanwhile I'm so proud that I'm keeping my hobby project under 10k lines and spend time trying to delete code for my own sanity
- gamblor956 1mo ago"startup" and "legacy codebase" are diametrically opposed concepts. And if you're saying (based on your other comments) that a 6 month window is enough to create a legacy codebase...that indicates a serious lack of experience or understanding as to what a legacy codebase is, or why they exist.
- nujabe 1mo agoexactly. Usually legacy code forms when people lose context and confidence in parts of the codebase due to staff turnover etc and ppl avoid touching or enhancing those parts for long periods. Six months is a short time to accrue that much tech debt, its enough time where most of the people who created that "legacy" are probably still around. As you said indicates bigger problems.
- hunterpayne 1mo agoSo basically any LLM codebase of sufficient size is immediately legacy.
- deleted 1mo ago[deleted]
- sbarre 1mo agoMan, so many people in this thread just arguing pointless semantics, making weirdo absolutist (and incorrect) statements. Accept that other people may ascribe different meanings/interpretations to words than you, and that if your reading of their statement doesn't make sense to you, perhaps you are simply reading it wrong. Trying to hold someone else to your definition of words suits what purpose exactly? Are you just trying to "win" ?
- loose-cannon 1mo agoI agree with your larger point. Though I think it's pretty natural to wonder how the poster ended up with a multi million line codebase.