Regardless of what we end up moving forward with, I think we need to use "Assisted-by" just like we use "Co-authored-by".
On Thu, Sep 24, 2026 at 7:59 PM Jane H <[email protected]> wrote: > I've been reviewing AI-assisted PRs from new contributors lately. > > The main concern I see is that: committers' review is already the > bottleneck of our delivery speed, but LLM-assisted PRs can make PR review > significantly harder, therefore put even more load on reviewers. Without > clear policy, guidance, and aligned expectations from the community, I > worry that increased use of AI can make our delivery speed slower rather > than faster. > > Sharing several challenges I met when reviewing AI-assisted PRs recently: > > 1. How do we put the principle that "contributors are responsible for > the code they submit" into practice? > 1. How does a contributor know they indeed understand every line of > code in their PR? This can be harder than it sounds. Imagine a new > contributor who vibe-codes a PR, reads through every line, feels that > the > code makes sense, and it passes several AI review tools. Is that enough? > I'd say no. For example, if this PR involves sending a new message to a > client, then I think a client and server setup for end-to-end manual > testing is needed. If a PR adds a metric, then I think spinning up a > cluster and watching the metric changes is needed. Such knowledge isn't > necessarily straightforward to new-comers. > 1. I think formal guidance on how to verify (e.g. testing env > setup) and what needs to be verified will be helpful. > 2. If a reviewer suspects that a contributor does not actually > understand their code, what should this reviewer do? In my own > experience, > I point out what's wrong in the code, but I don't think it is helpful to > simply blame the contributor for not understanding their submission. In > most cases, I don't have strong evidence that a mistake came from > AI-generated code and from the contributor failing to review it > carefully. > Human-written code can make similar mistakes too. And even if I know for > sure it's from AI assistance, what should I do? > 3. As PR review is async, sometimes a PR review will go straight to > contributors' claude. For example, if I ask, “Did you try testing > against > X?”, and the contributor asks claude to test against X then responds, > “Yes, > I tried it and it works,” I may trust them and approve the PR. But what > if > that answer turns out to be claude's hallucination? How should > responsibility work in that situation? > 2. More load on reviewers, more load on verification. Because I don't > currently know how the contributor's responsibility can be enforced in > practice, when I see a PR with LLM content, I have less confidence that the > PR is validated by human. In my own experience, I've had to ask > contributors how they've tested and why they think it's working, and tell > them what manual testing is needed. Often times I need to perform those > tests by myself instead, some are tests that I might not have needed to > perform in the same way in pre-AI era. Therefore I propose: > 1. Formal guidance on verification, as mentioned above. > 2. A PR template section that asks contributors to explain what > testing they've done beyond the unit tests and integration tests > included > in the PR. > 3. Disclosure of AI assistance, including which parts of the PR > were AI-assisted. > 3. Potentially misaligned expectation of delivery speed. Consider a > situation where someone comes to me with a new feature consisting of > hundreds of new files generated by LLM in a day saying they verified it and > asks for a review. What am I supposed to do? In my humble opinion, > reviewers should still review line-by-line, and as long as this holds true, > the high productivity of AI can never translate to the high delivery speed > as people wish. Various AI PR review tools can only help a bit but never > resolve the fundamental problem. I'm very open to different opinions here, > but I hope the community can align expectations. > > Overall, I think LLM is NOT just "another tool". None of previous tools > like IntelliJ has caused the above challenges. We have real problems to > solve here, and I think we would benefit from aligned expectation and > guidance, in addition to policies. > > > Jane He > > On Thu, Sep 24, 2026 at 5:40 PM Caleb Rackliffe <[email protected]> > wrote: > >> Blake, I’d support those 3 guidelines. >> >> One hostile reaction to them would, I’m guessing, be that guideline >> number 1 is too weak, and that the burden of quality would continue to rest >> entirely on committer reviewers. I suppose my reply there would be that >> anyone who continually spams the project with patches they do not fully >> understand wound incur a pretty heavy reputational penalty and the problem >> would more or less sort itself out. >> >> >> > On Sep 24, 2026, at 6:07 PM, Benedict Elliott Smith < >> [email protected]> wrote: >> > >> > For the record Josh, I am including pre-3.0. I was involved in >> customer support escalations for 1.2, 2.0 and 2.1: the software was shoddy, >> to put it mildly. 8099 was a symptom, not the disease. >> > >> > The project had a culture of doing stuff without sufficient care or >> consideration. This is by no means a simple matter of needing more testing >> or less timeline pressure, nor is it easy to define a "bar" to ensure it >> does not regress. If we had simple metrics, we would have settled it a long >> time ago. >> > >> > You can still see customer scars crop up on forum discussions >> periodically. >> > >> > >> > On 2026/09/24 19:01:02 Josh McKenzie wrote: >> >>> Apache Cassandra was fundamentally undeployable for four years >> between Nov 2015 - 2019. >> >> CASSANDRA-8099 was a maximal manifestation of a specific approach to >> engineering and calendar constraints we've seen time and again on the >> project; I don't want us to conflate things here. That was a herculean >> monolithic body of work performed in inhuman conditions (in vim!) that was >> ultimately so invasive, all the unit tests in the code-base were commented >> out and Jake and I spent a grueling 1.5-2 months hand-rewriting basically >> all the unit tests in that code-base to get things to even build and run, >> much less pass. >> >> >> >> Massive blast radius changes that are un-sustainably complex, >> under-tested, where we don't property, fuzz, check coverage, check >> complexity, or A/B compare against a known good system (i.e. pre/post) >> correctness testing are going to destabilize the database at any time under >> any regime of tooling. We certainly could speed-run our way back into >> destabilization with LLM's as they are a force multiplier for both the good >> and the bad of one's engineering practices, but that's a solvable problem >> by better defining what our bars of quality are (Definition of Done >> anyone?) and holding ourselves accountable to delivering at that bar. >> >> >> >> On Thu, Sep 24, 2026, at 2:40 PM, David Capwell via dev wrote: >> >>>> >> >>>> >> >>>> if you really want to pursue it I would ask that we do it offline to >> avoid polluting an already busy conversation >> >>>> >> >>> People are directly responding saying that they feel discrimination >> currently and that the policy tries to codify that discrimination, so I >> feel its 100% on topic. This thread has presented 0 evidence that LLM usage >> has lowered the quality of contributions merged and has so far been vibes >> and feeling; I have yet to see any evidence to justify such discrimination >> so I will keep pushing back until such evidence is presented so we can have >> a informed debate. >> >>> >> >>>> namely how we handle shallow and localised bug fixes. I would be >> happy adding a clear entry to the “Permitted” section for this. No doubt >> there are many refinements needed to the Restricted text as well, that >> might also capture some of your concerns. >> >>>> >> >>> I will not sign off on cherry picking areas where "safe" to use a >> tool; so no it does not capture my concerns. >> >>> >> >>> >> >>> >> >>>> I don't know if everyone remembers, but ten years ago Cassandra was >> full of serious correctness and stability issues. Despite developing it, I >> would not have run it myself or recommend that anyone use it. We have dug >> ourselves out of that hole, but it took years of discipline and effort, and >> we're still (deservedly) recovering our reputation. >> >>>> >> >>>> Let's use this new technology to improve the quality of our >> contributions, not squander our hard-earned gains in the name of speed. It >> will be hard to recover our reputation a second time. >> >>>> >> >>> I do recall the 3.x line and put in a significant amount of effort to >> harden it. There were behaviors I noticed after joining Cassandra that I >> feel directly contributed to 3.0 and the decade of catch up; behaviors that >> still linger in parts of the community today. >> >>> >> >>> As I look on trunk and look at committed code and trace back to PRs >> and JIRA I see the following: >> >>> >> >>> • large patches approved without comments >> >>> • 0 evidence that tests were run >> >>> I then look at our CI and see tests failing for months. As you start >> to triage you start to see some of them show real issues; yet they linger >> for months not being addressed... when CI is unstable it takes a lot of >> effort to triage "did my patch break the test", and I have seen time and >> time again people do not put in that effort, and shrug off as "its just a >> flakey test"; then our CI failure rate grows. >> >>> >> >>> Non of this has anything to do with LLMs but LLMs running in this >> environment is far more dangerous as there are not checks in place to "hold >> the bar". I am all for raising the bar universally; expecting both humans >> and LLMs to match that bar. >> >>> >> >>>> `I’d support something that boils down to roughly this: >> >>>> >> >>>> 1.) 2 committers must understand an LLM-assisted change before it >> commits. (Perhaps separately we can explore the question of why we haven’t >> added any new committers to the core project for about a year. I’m also >> still not entirely sure if it’s acceptable within our guidelines for a >> committer to +1 a patch after delegating review.) >> >>>> >> >>>> 2.) Patch authors must demonstrate enough understanding to discuss >> their own patch, whether or not parts of it are generated by an LLM. >> >>>> >> >>>> 3.) The “Assisted-by” tag should be used to indicate any non-trivial >> LLM usage in the generation of a patch, just like we have used >> Co-authored-by historically. >> >>>> >> >>>> 4.) Comments and other things that aren't the actual code (but could >> sow confusion) should be held to the same standard we'd expect from a human >> writer. If we don’t yet agree on that standard, we can formalize enough of >> it to guide both humans and LLMs. >> >> ` >> >>> I can get behind this proposal but i would tweak it as 1/2 i don't >> think really need to special case LLM usage >> >>> >> >>> 1. 2 committers must understand the change before it commits. >> >>> 2. Patch authors must demonstrate enough understanding to discuss >> their own patch >> >>> Nothing about those 2 need to be scoped to LLM usage and honestly >> matches most PMCs I have talked to understanding of our bar (as Benedict >> pointed out, the actual wording could be interpreted to allow rubber >> stamping from committer) >> >>> >> >>> As for 3 I am cool with this. ASF recommends the same (it says >> `Generated-by` but that discount's the human's effort) as its useful for >> audits and tooling. Having `Assisted-by` tag should not imply anything >> about the committed patch as it should have gone through the same bar we >> all expect; its just for tools auditing. >> >>> >> >>> >> >>>> On Sep 24, 2026, at 10:37 AM, Aleksey Yeshchenko via dev < >> [email protected]> wrote: >> >>>> >> >>>> Meant "doing away with", sorry. Non-native speaker with a headache >> here. Thanks Caleb for spotting. >> >>>> >> >>>>> On 24 Sep 2026, at 17:35, Aleksey Yeshchenko via dev < >> [email protected]> wrote: >> >>>>> >> >>>>> P.S. I assume it's obvious from the text above that I don't believe >> that getting away with human code review is a viable option. >> >>>> >> >>>> >> >>>>> On 24 Sep 2026, at 17:37, Štefan Miklošovič <[email protected]> >> wrote: >> >>>>> >> >>>>> Good call on checkerframework, we even have a patch for it. Work of >> >>>>> Jacek Lewandowski. We might just drive it to completion. Using AI >> for >> >>>>> finishing it would be quite ironic. >> >>>>> >> >>>>> (1) https://github.com/apache/cassandra/pull/2370 >> >>>>> >> >>>>> On Thu, Sep 24, 2026 at 6:19 PM Jon Haddad <[email protected]> >> wrote: >> >>>>>> >> >>>>>> There are some really good points being brought up about stability >> of the codebase, maintainability, quality of reviews, correctness bugs, and >> I agree with all of them. I think it would be helpful to take a step back >> and consider how those bugs got there in the first place, how they were >> fixed, and what we could do to further advance the codebase so they don't >> creep back. LLMs can be used either with very tight guardrails, or in >> what's effectively YOLO mode, and there's a big difference in the quality >> of the results you get. >> >>>>>> >> >>>>>> One thing to keep in mind, a lot of the initial code in C* was >> added without comprehensive testing. I hope we can all agree that it's a >> lot easier to break code that doesn't have high quality tests. During the >> code freeze, a lot of people people spent several years relentlessly >> finding and fixing bugs. This was probably a pretty frustrating time for >> anyone who was focused on fixing other people's bugs when they wanted to >> build features. I think we should recognize the effort here and appreciate >> the foundation that the project stands on now. I can understand how anyone >> involved with this effort would be apprehensive about seeing years of their >> life swept away by an agent that was driven by goal seeking to remove all >> the tests that it broke instead of fixing them. >> >>>>>> >> >>>>>> When I picked up the work to improve cursor compaction, the first >> thing I asked myself was how can I make sure I don't break this? How do I >> even know it works properly? There were some tricky parts to the code, and >> I really didn't want to come in and immediately break stuff. That's why I >> started with an entire patch dedicated to adding test infra to it. 90% of >> the patch was tests, and in my other cursor patches, it remains *at least* >> 80% of my patches. It was a *lot* faster to add almost 10K lines of tests >> that handled a byte for byte differential testing paired with harry to find >> over 30 bugs that caused cursor to corrupt results. Range tombstones alone >> were at least a dozen bugs, but I also found issues with static columns, >> reverse ordering, etc. Randomizing schemas and data in burn tests to >> generate different shapes of data, to ensure they all result in the same >> output at the end. JMH tests to ensure there weren't performance >> regressions, hours of profiling. These were all a *lot* easier to do with >> the LLM helping me out. In the process I've found bugs that have been >> lingering in the codebase for years. >> >>>>>> >> >>>>>> That's a long story, but hopefully we all agree that having >> comprehensive tests is a great way to ensure that both humans and LLMs >> don't break things that are working. >> >>>>>> >> >>>>>> The lesson: we need to keep improving our testing. Everything >> that we touch, should be left in a better state than how we found it with >> regard to test coverage. >> >>>>>> >> >>>>>> Test coverage isn't everything though, there's always little >> subtle bugs that don't get found in testing, that can slip in despite our >> best efforts. It's debatable if humans will be as good as agents for >> coding in the long term, for spotting small defects. I sincerely doubt >> it. For the time being though, we still have people involved. It's >> probably a good time to start using more static analysis tools to identify >> problematic code and to add this to CI. Dmitry had a suggestion recently >> for checkerframework to detect leaking contexts, a problem he spotted when >> reviewing my branch. It would be great to have that integrated into our CI >> and dev workflow so we can simply avoid an entire class of bugs. >> >>>>>> >> >>>>>> There's also PMD, which is excellent for finding code that can be >> hard to understand. I *highly* suggest you all run PMD to analyze for >> cognitive complexity and high npath scores. This was made popular by the >> folks at Sonar and I've found it to be an excellent feedback mechanism for >> structuring code. The default max they set is 15, which is the point where >> it starts to become difficult to verify something works without making a >> massive investment. We've got areas in the codebase that are in the >> hundreds, and some parts even higher. These have been contributed by >> humans, and are all high risk points for both humans and agents to start >> messing around with. They're also in some fairly critical areas that are >> very likely to break, so I understand why people would not want an agent >> anywhere near it. >> >>>>>> >> >>>>>> Unfortunately, it's not an easy problem to address. There's so >> many places where the code is structured in a way that has so many >> branches, so many conditions, that it's effectively impossible for a human >> to understand, creating a fear of messing around in it. There's plenty of >> areas that deserve extreme scrutiny, and we should be careful of what we >> add, whether it's human or agent. >> >>>>>> >> >>>>>> The codebase today requires a high degree of internal knowledge to >> navigate. There's land mines everywhere. We should be looking to make >> conscious improvements by moving the code forward, so it's easier to make >> changes to small, well tested components with minimal side effects. Not >> making it harder for people to use the tools that aid in that process. >> >>>>>> >> >>>>>> Here's what we could do to achieve the underlying goal of not >> breaking the DB: >> >>>>>> >> >>>>>> Add cognitive complexlity and npath via PMD as a feedback >> mechanism. >> >>>>>> >> >>>>>> Code that's hard to understand is hard to review. It's also hard >> to test. Let's break down the complex code so more people can contribute, >> safely. >> >>>>>> >> >>>>>> Add checkerframework to our tooling, >> >>>>>> >> >>>>>> Properly annotate the codebase for it and reduce the surface area >> that things can break. Less brittle codebase = we can move faster. >> >>>>>> >> >>>>>> Use jacoco to find areas of the codebase with poor testing. >> >>>>>> >> >>>>>> Let's improve the test coverage there, LLMs are great for this. >> We have a ton of static tests, these can become more dynamic, >> parameterized, and leverage harry. >> >>>>>> >> >>>>>> Refactor parts of the codebase that have high cognitive >> complexlity and NPath scores. >> >>>>>> >> >>>>>> This should be lowered over time to meet some high watermark, say >> 25 maximum, although I'd prefer 15 which is where the Sonar folks settled. >> >>>>>> >> >>>>>> Move forward moving the codebase to a more modular structure >> >>>>>> >> >>>>>> We've talked about Gradle on and off - but it can really be a huge >> help with incremental, modular builds. This is pretty easy to do with an >> agent and we could have it done in a couple days. >> >>>>>> >> >>>>>> Enforce boundaries with ArchUnit >> >>>>>> >> >>>>>> If we want to enforce certain code boundaries, this is the way to >> do it. Should not be part of manual review. >> >>>>>> >> >>>>>> Add LLM review for all incoming PRs before a human >> >>>>>> >> >>>>>> The goal here is to automate the initial part of the review >> process that reviewers should spot, and raise the bar for the initial >> contribution. When the code gets reviewed by a human, it should already >> have passed a large variety of initial checks. This should shorten the >> review cycle and result in higher quality patches. I've had Claude >> reviewing all my PRs in my personal projects for a while now and it >> consistently gives great feedback that I almost always incorporate. >> >>>>>> >> >>>>>> In my ideal world, we'd also auto-format all code >> >>>>>> >> >>>>>> Consistent formatting throughout the codebase would be amazing, >> but that's just one man's dream. >> >>>>>> >> >>>>>> Hopefully there's at least a couple things in this list we could >> move forward with in the short term, as it'll help improve the code quality >> regardless of how it's created. >> >>>>>> >> >>>>>> Jon >> >>>>>> >> >>>>>> https://checkerframework.org/manual/#aliasing-leaking-contexts >> >>>>>> https://www.sonarsource.com/docs/CognitiveComplexity.pdf >> >>>>>> https://pmd.github.io/pmd/pmd_rules_java_design.html >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> >> >>>>>> On Thu, Sep 24, 2026 at 7:38 AM C. Scott Andreas < >> [email protected]> wrote: >> >>>>>>> >> >>>>>>> From Benedict: >> >>>>>>> >> >>>>>>> “I don't know if everyone remembers, but ten years ago Cassandra >> was full of serious correctness and stability issues. Despite developing >> it, I would not have run it myself or recommend that anyone use it. We have >> dug ourselves out of that hole, but it took years of discipline and effort, >> and we're still (deservedly) recovering our reputation.” >> >>>>>>> >> >>>>>>> Expanding on this point for those who may not have been active in >> the project at this time — >> >>>>>>> >> >>>>>>> Apache Cassandra was fundamentally undeployable for four years >> between Nov 2015 - 2019. The database literally lost data if you ran a >> read-only SELECT query ordered descending (C-14513, C-14515). If you >> haven’t read these tickets before, please take a moment to do so. >> >>>>>>> >> >>>>>>> It took years of careful work via property-based testing, >> fuzzing, and deterministic simulation to restore Cassandra’s status as a >> usable system of record. Once 14513 and 14515 were identified, nearly 30 >> additional critical data loss and incorrect response bugs were identified. >> >>>>>>> >> >>>>>>> It is essential for the project’s future that we don’t regress to >> this state chasing AI-generated features motivated by fear. The fact that >> examples cited in this thread which boast shiny features but have critical >> shortcomings unknown to their author supports this argument. >> >>>>>>> >> >>>>>>> The most common path for large corpuses of AI-generated software >> is elation and reveling in a feature matrix, followed by abandonment. >> >>>>>>> >> >>>>>>> I endorse this point: >> >>>>>>> >> >>>>>>> “Let's use this new technology to improve the quality of our >> contributions, not squander our hard-earned gains in the name of speed. It >> will be hard to recover our reputation a second time.” >> >>>>>>> >> >>>>>>> Patrick, I don’t want your note regarding a TCM issue to go >> unaddressed. Please file a Jira ticket and the patch if you like. I can’t >> comment on the patch as I haven’t seen it, but together we will solve the >> problem. >> >>>>>>> >> >>>>>>> – Scott >> >>>>>>> >> >>>>>>>> On Sep 24, 2026, at 4:01 AM, Benedict Elliott Smith < >> [email protected]> wrote: >> >>>>>>>> >> >>>>>>>> Hi Patrick, >> >>>>>>>> >> >>>>>>>> As I mentioned in my reply to David, I would be happy to create >> a carve out for shallow and localised bug fixes in the "Permitted" section. >> Would this alleviate some of your concerns regarding your ability to >> contribute to the project? >> >>>>>>>> >> >>>>>>>> I appreciate your pointing out Ferrosa's Accord implementation >> however, as it is a *great* example of the problems we're leaping into. I >> took a look, and within about 30s found that the protocol is fundamentally >> incorrect, having failed to address CASSANDRA-18365. This is despite >> claiming to be tested with Jepsen that should in principle find this fault. >> I followed up by using Claude to interrogate the implementation further, >> and immediately found other serious correctness issues. >> >>>>>>>> >> >>>>>>>> I use LLMs daily now to help facilitate Accord development, and >> while they are powerful they are NOT able to author the code themselves, >> even when building upon a strong human-authored foundation. >> >>>>>>>> >> >>>>>>>> I don't know if everyone remembers, but ten years ago Cassandra >> was full of serious correctness and stability issues. Despite developing >> it, I would not have run it myself or recommend that anyone use it. We have >> dug ourselves out of that hole, but it took years of discipline and effort, >> and we're still (deservedly) recovering our reputation. >> >>>>>>>> >> >>>>>>>> Let's use this new technology to improve the quality of our >> contributions, not squander our hard-earned gains in the name of speed. It >> will be hard to recover our reputation a second time. >> >>>>>>>> >> >>>>>>>> >> >>>>>>>>> On 2026/09/23 19:16:17 Patrick McFadin wrote: >> >>>>>>>>> I was waiting for this moment to hit our project and I'm glad >> we're here. I >> >>>>>>>>> am deeply concerned for our project and its future, as we have >> increasingly >> >>>>>>>>> made it difficult to contribute. I had hoped that this new era >> of >> >>>>>>>>> software tools powered by AI would expand the project's reach >> and bring >> >>>>>>>>> more diverse thoughts and ideas. This policy proposal is the >> exact opposite >> >>>>>>>>> of what we need. We have been sitting on a Cassandra 6 release >> alpha for >> >>>>>>>>> months. We need to accelerate and embrace new ways of being or >> be left >> >>>>>>>>> behind. As I read that policy, my first and gut level reactions: >> >>>>>>>>> - It comes across as elitist and class protectionism. Committer >> should not >> >>>>>>>>> be special but this proposal makes that designation even more >> sacred. >> >>>>>>>>> - It signals that our project is so fragile that only a few >> people "Really >> >>>>>>>>> understand it" That's some SQLite vibes right there. >> >>>>>>>>> - Trying to fix a problem that doesn't exist >> >>>>>>>>> Sadly, i think this policy change would also exclude a lot of >> comitters. >> >>>>>>>>> We aren't alone in this moment. The Linux project just went >> through >> >>>>>>>>> this. You can find the thread with a simple Google, but similar >> hard >> >>>>>>>>> feelings were being expressed "AI is going to ruin our >> project!", "The >> >>>>>>>>> unwashed masses are going to contribute terrible code!", "We >> have to >> >>>>>>>>> protect our precious status as Linux maintainers!" Linus being >> Linus, was >> >>>>>>>>> deeply invloved and they adopted a super simple statement that >> covers all >> >>>>>>>>> bases. Human or Human using AI. “You are expected to understand >> and to be >> >>>>>>>>> able to defend everything you submit.” Love that. >> >>>>>>>>> In the larger picture, I'll restate. I'm worried for our >> project. In late >> >>>>>>>>> 2025(Opus 4.5 IYKYK), early 2026, AI coding LLMs turned a real >> corner and >> >>>>>>>>> in the hands of somebody that knows how to build software, this >> tool is >> >>>>>>>>> like jet fuel. Here's some examples of new projects being hyper >> fueled by >> >>>>>>>>> AI coding tools. >> >>>>>>>>> Apache Iggy - Complete rust replacement of kafka. Crazy fast >> velocity >> >>>>>>>>> Turso - Rust re-write of SQLite >> >>>>>>>>> Bun - Rust re-write of itself from Zig. >> >>>>>>>>> Think this couldn't happen to us? Already has: >> >>>>>>>>> https://github.com/ferrosadb/ferrosa. Ben is using it to power >> his own >> >>>>>>>>> startup, but it was him alone using a ton of local AI coding >> agents. He >> >>>>>>>>> even implemented Accord. Yeah... >> >>>>>>>>> The cracks are already starting to show. There is a black >> market economy of >> >>>>>>>>> Cassandra patches happening now. Not going to name names or >> call people >> >>>>>>>>> out, but there are fixes and optimizations living in branches >> outside of >> >>>>>>>>> the Cassandra project. Why? I'll use myself as an example. I >> fixed a nasty >> >>>>>>>>> bug I ran into with TCM a few weeks ago. Wrote the tests. It >> passes CI and >> >>>>>>>>> lives in my personal branch. I'm sitting here really wondering >> if I want to >> >>>>>>>>> go through the ritual humiliation of being roasted for using AI >> to fix it. >> >>>>>>>>> Me. I am worried about contrinuting code the Cassandra. What >> the hell does >> >>>>>>>>> that say? >> >>>>>>>>> I have my CQLite project that I've been doing a release around >> once a >> >>>>>>>>> month. I would love to donate that to the Cassandra project but >> I wouldn't >> >>>>>>>>> if it essentially killed any progress. >> >>>>>>>>> My larger counter proposal would be to: >> >>>>>>>>> - Adopt the “You are expected to understand and to be able to >> defend >> >>>>>>>>> everything you submit.” approach the Linux project has adopted. >> >>>>>>>>> - Loosen up the contributor process and our worry on trunk. Let >> 1000 >> >>>>>>>>> flowers bloom and bring it in. >> >>>>>>>>> - And finally, to give some people more peace of mind and open >> more doors, >> >>>>>>>>> adopt what other projects have done and provide more >> pluggability. Let new >> >>>>>>>>> ideas have an easy place to connect. >> >>>>>>>>> We are at a fork in the road. What are we going to do? And then >> I have to >> >>>>>>>>> ask myself, what am I going to do as a contributor? >> >>>>>>>>> Patrick >> >>>>>>>>> On Wed, Sep 23, 2026 at 6:16 AM Blake Eggleston < >> [email protected]> >> >>>>>>>>> wrote: >> >>>>>>>>>> I’m not necessarily opposed to having a policy, but so far we >> have some >> >>>>>>>>>> specific proposals addressing a problem statement that’s very >> nebulous. >> >>>>>>>>>> What is the community failing to do on its own that we’re >> trying to correct >> >>>>>>>>>> with policy? What outcomes are we trying to create or prevent? >> Having some >> >>>>>>>>>> examples and specific problems to discuss would help focus the >> conversation. >> >>>>>>>>>>> On Wed, Sep 23, 2026, at 4:34 AM, Shailaja Koppu via dev >> wrote: >> >>>>>>>>>> Benedict, >> >>>>>>>>>> Thanks for clarifying. My concern still remains. This criteria >> would be >> >>>>>>>>>> difficult to define and apply consistently. What counts as >> “similar” scope >> >>>>>>>>>> or area, “mostly correct,” or sufficiently independent work? >> More >> >>>>>>>>>> importantly, how do we prevent such vague criteria from >> creating an >> >>>>>>>>>> informal hierarchy where some contributors work is routinely >> accepted while >> >>>>>>>>>> others is routinely rejected? >> >>>>>>>>>> If the intent is to limit AI-assisted code changes to Cassandra >> >>>>>>>>>> contributors, or to contributors who have previously worked in >> that >> >>>>>>>>>> component without AI, that would at least be clear and >> enforceable. >> >>>>>>>>>>> On Sep 23, 2026, at 12:01 PM, Benedict Elliott Smith < >> >>>>>>>>>> [email protected]> wrote: >> >>>>>>>>>>> Core code changes >> >>>>>>>>>>> Chris: Do you object to the first or second line you quote? >> Because the >> >>>>>>>>>> first line is effectively motivation for the second line, and >> can be >> >>>>>>>>>> removed (or more clearly combined). If it’s the second line, >> then I do not >> >>>>>>>>>> think this is an unreasonable expectation, and we can get into >> a proper >> >>>>>>>>>> debate about it. >> >>>>>>>>>>> Shailaja, since you only snipped the first sentence, your >> concerns might >> >>>>>>>>>> also be mostly answered by this clarification? “Minimal >> third-party >> >>>>>>>>>> guidance” implies you have some concerns about the second >> line, but all of >> >>>>>>>>>> our policies have some ambiguity because legalese is even >> worse. I don’t >> >>>>>>>>>> think the ambiguity here would be challenging to navigate >> though we can >> >>>>>>>>>> certainly refine it. This specific snippet is meant to convey >> an >> >>>>>>>>>> expectation that a contributor has autonomously produced >> patches of similar >> >>>>>>>>>> scope that were mostly correct, so that they have demonstrated >> the level of >> >>>>>>>>>> understanding necessary to guide another party to a successful >> patch (i.e. >> >>>>>>>>>> an LLM in this case). >> >>>>>>>>>>> On 2026/09/23 10:54:16 Benedict Elliott Smith wrote: >> >>>>>>>>>>>> Thanks everyone for your input so far. I’ll respond in brief >> to the >> >>>>>>>>>> main themes, in (mostly) separate emails so they can each have >> their own >> >>>>>>>>>> debate chain. >> >>>>>>>>>>>> Should we have a policy (Blake/Josh*/Jon/Dinesh) >> >>>>>>>>>>>> I think we would all agree that LLMs represent the biggest >> change to >> >>>>>>>>>> this community (and software more generally) since its >> inception, and we >> >>>>>>>>>> all now have enough experience with the technology to have >> formed opinions >> >>>>>>>>>> about how it is best managed. We also evidently have not all >> arrived at the >> >>>>>>>>>> same conclusions. In this situation, it would be an abdication >> of our >> >>>>>>>>>> responsibilities as a management committee to not agree *some* >> policy. >> >>>>>>>>>>>> I intend to conduct straw polls as the discussion evolves, >> so if you >> >>>>>>>>>> prefer an alternative policy - or modifications to this policy >> - I would >> >>>>>>>>>> encourage you to make those alternative proposals. >> >>>>>>>>>>>> *Veto/Consensus (Josh) >> >>>>>>>>>>>> It was fair to call out my poor use of language on this >> topic, so let >> >>>>>>>>>> me rephrase a little. The community is built on consensus, and >> work should >> >>>>>>>>>> not be merged when there are outstanding concerns to address. >> The explicit >> >>>>>>>>>> -1 should only be used rarely, because the prior expectation >> should prevent >> >>>>>>>>>> it ever being needed. I (and others) have outstanding concerns >> on LLM >> >>>>>>>>>> generated work that can only be addressed through this process >> right here, >> >>>>>>>>>> so to merge such work while maintaining the community’s >> consensus we must >> >>>>>>>>>> agree some policy. >> >>>>>>>>>>>> On 2026/09/23 09:58:27 Shailaja Koppu via dev wrote: >> >>>>>>>>>>>>> I am strongly -1 on this >> >>>>>>>>>>>>> - Core code changes made by LLM may only be proposed by >> contributors >> >>>>>>>>>> with demonstrated expertise >> >>>>>>>>>>>>> That creates a new, subjective privileged class of >> contributors and >> >>>>>>>>>> turns a tool choice into an eligibility test. Who decides >> whether expertise >> >>>>>>>>>> has been “demonstrated,” what counts as “minimal third-party >> guidance,” and >> >>>>>>>>>> how could those judgments be applied consistently or fairly? >> >>>>>>>>>>>>> Apache already has a better model, anyone may contribute, >> trust and >> >>>>>>>>>> additional repository privileges are earned transparently over >> time. The >> >>>>>>>>>> ASF describes its communities as flat, and says that newcomer >> ideas have as >> >>>>>>>>>> much input as those from original creators. We should not add >> a separate, >> >>>>>>>>>> informal hierarchy in which certain people may use common >> development tools >> >>>>>>>>>> while others may not. >> >>>>>>>>>>>>>> On Sep 23, 2026, at 6:33 AM, Chris Lohfink < >> [email protected]> >> >>>>>>>>>> wrote: >> >>>>>>>>>>>>>> - Core code changes made by LLM may only be proposed by >> contributors >> >>>>>>>>>> with demonstrated expertise >> >>>>>>>>>>>>>> - Must have produced similar patches in size, scope and >> area >> >>>>>>>>>> unassisted and with minimal third-party guidance >> >>>>>>>>>>>>>> I really don't like this one or its wording. Definitely >> too "the >> >>>>>>>>>> peasants are getting uppity lets build a wall". Lets not let a >> subjective >> >>>>>>>>>> thing like demonstrated expertise (who decides that?) be if >> it's ok or not. >> >>>>>>>>>> Hold the same standards for code quality and process for it >> all. I don't >> >>>>>>>>>> want this to be: only people on the storage team in Apple can >> use AI. >> >>>>>>>>>>>>>> Chris >> >>>>>>>>>>>>>> On Wed, Sep 23, 2026 at 12:16 AM <[email protected] >> <mailto: >> >>>>>>>>>> [email protected]>> wrote: >> >>>>>>>>>>>>>>> I agree with Stefan and think this is both a reasonable >> and >> >>>>>>>>>> thoughtful proposal. >> >>>>>>>>>>>>>>> Here are some things I like about it: >> >>>>>>>>>>>>>>> – It outlines areas where LLM usage is unambiguously >> useful to the >> >>>>>>>>>> project’s developers and users. >> >>>>>>>>>>>>>>> – It defines a spectrum of recommendations and cautions. >> >>>>>>>>>>>>>>> – The only prohibited areas are extremely narrow and say >> nothing >> >>>>>>>>>> about code at all. >> >>>>>>>>>>>>>>> Some in this thread are responding as if this proposal >> seeks to >> >>>>>>>>>> prohibit or sharply limit use of LLMs. In fact, it’s one of >> the most open >> >>>>>>>>>> and welcoming I’ve seen for an OSS project of our size where >> many are >> >>>>>>>>>> adopting policies that simply ban them entirely. I’ve >> re-appended the >> >>>>>>>>>> proposal below my message as it seems to have been lost in >> threaded >> >>>>>>>>>> replies, and would encourage folks to give it a second read. >> >>>>>>>>>>>>>>> Some brief thoughts based on my own use of LLMs: >> >>>>>>>>>>>>>>> – I find them fantastically useful for reviewing and >> identifying >> >>>>>>>>>> problems that have slipped through review - primarily via Alex >> Petrov’s >> >>>>>>>>>> /deep-review skill, which I have running in a VM in a loop >> executing over >> >>>>>>>>>> every new commit in the project as of a few days ago. I will >> be posting a >> >>>>>>>>>> few hand-authored Jira tickets based on findings that appear >> legitimate to >> >>>>>>>>>> me. For now, the loop is posting them as issue drafts for my >> own review on >> >>>>>>>>>> my personal fork which you can find here: >> >>>>>>>>>> >> https://github.com/cscotta/cassandra/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug >> >>>>>>>>>>>>>>> – They’re great for enabling use of model checkers and >> formal >> >>>>>>>>>> methods where such work would have previously been >> prohibitively expensive, >> >>>>>>>>>> such as Blake’s work on a TLA+ proof of aspects of Mutation >> Tracking and >> >>>>>>>>>> Benedict/Fedor’s work on a machine-checkable proof of the >> Accord protocol >> >>>>>>>>>> in Lean. >> >>>>>>>>>>>>>>> – They are stunning for allowing me to experiment with >> ideas that >> >>>>>>>>>> would have otherwise been a summer internship’s scope of work. >> Some >> >>>>>>>>>> examples include an io_uring prototype, exploring the impact of >> >>>>>>>>>> page-aligned compressed chunk sizes, an API shim bridging the >> 3.x and 4.x >> >>>>>>>>>> Java Drivers, and potential enhancements to Zstandard. >> >>>>>>>>>>>>>>> – And they shine when given grunt-work that is critical >> to the >> >>>>>>>>>> project but a miserable labor for humans, such as triaging, >> reproducing, >> >>>>>>>>>> and root-causing flaky tests, which David Capwell now has >> running in a loop >> >>>>>>>>>> to help us improve CI stability in the project. >> >>>>>>>>>>>>>>> I never thought I’d be so positive on what’s possible via >> language >> >>>>>>>>>> models a year ago. At the same time, I also agree that they >> present >> >>>>>>>>>> challenges and risks that can be managed through thoughtful >> discussion and >> >>>>>>>>>> policy. Some of the concerns that I think are important to >> guard against >> >>>>>>>>>> include: >> >>>>>>>>>>>>>>> – Asymmetry of effort between author and reviewers: As >> >>>>>>>>>> token-generating machines, LLMs can generate diffs of >> extraordinary size >> >>>>>>>>>> very rapidly. /deep-review is great for chewing through diffs >> and >> >>>>>>>>>> identifying defects. But it should be used by the contributor >> themselves to >> >>>>>>>>>> identify issues – not to replace the role of the reviewer with >> more >> >>>>>>>>>> electricity. The role of the reviewers extends beyond >> identifying and >> >>>>>>>>>> highlighting defects. It encompasses architecture, harmony >> with the >> >>>>>>>>>> existing codebase, thinking ahead to future evolution of the >> project, and >> >>>>>>>>>> replicates context on the project as new code is committed. >> These functions >> >>>>>>>>>> cannot be automated away. >> >>>>>>>>>>>>>>> – Hesitancy of authors to engage manually with code they >> have >> >>>>>>>>>> generated: This is not specific to Cassandra, but it is a >> behavior that I >> >>>>>>>>>> have seen in several “highly-electric” projects. There’s a >> bimodal tendency >> >>>>>>>>>> toward code that is entirely generated or entirely >> human-authored - but it >> >>>>>>>>>> is rare for someone to prepare an AI-authored patch to take an >> offramp and >> >>>>>>>>>> spend a significant amount of time refining the work by hand >> in an IDE. >> >>>>>>>>>> This hesitancy toward human participation in authorship of >> LLM-generated >> >>>>>>>>>> code is very concerning to me. >> >>>>>>>>>>>>>>> – Harmony with the existing codebase: Due to the >> tunnel-vision of >> >>>>>>>>>> context windows, LLMs are generally unaware of conventions and >> norms >> >>>>>>>>>> present in codebases and very frequently reinvent concepts in >> a generation >> >>>>>>>>>> turn to suit a goal without view of the project’s overall >> architecture. >> >>>>>>>>>> This results in a profusion of messy and duplicated concepts >> that gradually >> >>>>>>>>>> sprawl about a codebase. >> >>>>>>>>>>>>>>> Again, none of these are grounds for prohibition of usage >> of >> >>>>>>>>>> language models in developing the project. They’re just >> problems we need to >> >>>>>>>>>> bear in mind and guard against – and I think the proposal is >> designed to do >> >>>>>>>>>> just that. >> >>>>>>>>>>>>>>> I’m thrilled by the potential of LLMs to improve Apache >> Cassandra >> >>>>>>>>>> and we already see it happening through a vast number of >> issues that are >> >>>>>>>>>> being reported and fixed. But there’s also danger in taking >> ATVs down a >> >>>>>>>>>> hiking trail full of people. >> >>>>>>>>>>>>>>> Regarding the prohibition on prose, I’ll simply say: I >> recently >> >>>>>>>>>> found myself in a scenario where I found a Claude-authored >> document so >> >>>>>>>>>> inscrutable that I piped it back into a model, directed it to >> rewrite it in >> >>>>>>>>>> ASD-STE100, read it myself, and responded based on the >> summarization. As a >> >>>>>>>>>> humanities grad, this is probably the worst language crime I >> have >> >>>>>>>>>> committed. But it was in response to language that was itself >> so >> >>>>>>>>>> idiosyncratic that it was unreadable to me in its original >> form. I hope >> >>>>>>>>>> this never happens in the Apache Cassandra project. >> >>>>>>>>>>>>>>> I’ll close with a quote from an excellent article written >> by Colin >> >>>>>>>>>> Breck, an engineer who works on large-scale data systems: >> >>>>>>>>>> >> https://blog.colinbreck.com/i-dont-want-to-read-what-you-didnt-write/ >> >>>>>>>>>>>>>>> Colin wrote: >> >>>>>>>>>>>>>>>> I don’t want to live in a world where you use AI to >> summarize >> >>>>>>>>>> something important into unreadable text, and then I use AI in >> an attempt >> >>>>>>>>>> to decipher it. I want to hear you, imperfections and all. I >> want your >> >>>>>>>>>> interpretation of aesthetics, beauty, quality, relationship, >> time. I want >> >>>>>>>>>> to know how you feel. I want you to cut through and tell me >> what really >> >>>>>>>>>> matters. >> >>>>>>>>>>>>>>>> Intentional writing will likely become more valuable. >> People who >> >>>>>>>>>> write, and write to think, to think deeply and carefully, or >> to create, to >> >>>>>>>>>> share, or to capture something important without explicitly >> expressing it >> >>>>>>>>>> will continue to write and produce original work. The people >> who never were >> >>>>>>>>>> writers will use AI to produce lots of text. >> >>>>>>>>>>>>>>> I hope that our culture can remain one of intentional >> writing and >> >>>>>>>>>> intentional engineering. I enjoy reading the voice of the >> author in >> >>>>>>>>>> comments, code, and tickets in Cassandra – the different ways >> we use >> >>>>>>>>>> language based on where we grew up and how we learned English, >> the >> >>>>>>>>>> translated idioms from our various backgrounds, and terse >> comments that >> >>>>>>>>>> recognize the difference between code whose function is >> obvious and what >> >>>>>>>>>> warrants genuine exposition. When I read code in Cassandra, >> it’s a delight >> >>>>>>>>>> to recognize the author based on their writing style before >> flipping on >> >>>>>>>>>> `git annotate` to reveal the origin. >> >>>>>>>>>>>>>>> I’d encourage folks to re-read the original proposal >> below. It is >> >>>>>>>>>> very permissive. The guidance strikes me not just as >> reasonable, but >> >>>>>>>>>> genuinely important to maintaining the health of the project. >> >>>>>>>>>>>>>>> – Scott >> >>>>>>>>>>>>>>> ===== >> >>>>>>>>>>>>>>> Encouraged: >> >>>>>>>>>>>>>>> - Reviewing and otherwise validating human-authored >> patches before >> >>>>>>>>>> submission >> >>>>>>>>>>>>>>> - Debugging, diagnosing etc >> >>>>>>>>>>>>>>> Permitted: >> >>>>>>>>>>>>>>> - Generating or modifying tests, scripts, tooling or any >> other >> >>>>>>>>>> non-user facing changes >> >>>>>>>>>>>>>>> - Minor changes to human-authored patches that are >> carefully >> >>>>>>>>>> reviewed by the author >> >>>>>>>>>>>>>>> Restricted: >> >>>>>>>>>>>>>>> - Core code changes made by LLM may only be proposed by >> contributors >> >>>>>>>>>> with demonstrated expertise >> >>>>>>>>>>>>>>> - Must have produced similar patches in size, scope and >> area >> >>>>>>>>>> unassisted and with minimal third-party guidance >> >>>>>>>>>>>>>>> - Core code changes made by LLM require an additional >> reviewer >> >>>>>>>>>>>>>>> - LLM review is not a substitute for human review, and >> must be used >> >>>>>>>>>> only to augment a complete and independent human understanding >> of the patch. >> >>>>>>>>>>>>>>> Prohibited: >> >>>>>>>>>>>>>>> - All public prose must be human authored. This includes >> inline >> >>>>>>>>>> comments, docs, posts to Jira etc. >> >>>>>>>>>>>>>>> All LLM generated changes MUST be disclosed: >> >>>>>>>>>>>>>>> - Outlined to any reviewer; >> >>>>>>>>>>>>>>> - Summarised in the commit message; >> >>>>>>>>>>>>>>> - Large blocks or files must be individually marked with >> some agreed >> >>>>>>>>>> message like "created by <some AI>" >> >>>>>>>>>>>>>>> ===== >> >>>>>>>>>>>>>>>> On Sep 22, 2026, at 9:13 PM, Dinesh Joshi < >> [email protected] >> >>>>>>>>>> <mailto:[email protected]>> wrote: >> >>>>>>>>>>>>>>>> On Tue, Sep 22, 2026 at 3:28 AM Benedict < >> [email protected] >> >>>>>>>>>> <mailto:[email protected]>> wrote: >> >>>>>>>>>>>>>>>>> Restricted: >> >>>>>>>>>>>>>>>>> - Core code changes made by LLM may only be proposed by >> >>>>>>>>>> contributors with demonstrated expertise >> >>>>>>>>>>>>>>>>> - Must have produced similar patches in size, scope and >> area >> >>>>>>>>>> unassisted and with minimal third-party guidance >> >>>>>>>>>>>>>>>> I am -1 on this. This sounds like gate keeping attempt. >> It narrowly >> >>>>>>>>>> limits the pool to a few people on the project that have >> historically >> >>>>>>>>>> contributed to certain parts of the codebase. This policy will >> prohibit >> >>>>>>>>>> skilled software engineers with domain expertise from >> proposing LLM >> >>>>>>>>>> assisted changes simply because they have not contributed to >> the project. >> >>>>>>>>>> This is unrealistic and a net negative for the project to >> attract talent >> >>>>>>>>>> and grow our community. >> >>>>>>>>>>>>>>>>> - Core code changes made by LLM require an additional >> reviewer >> >>>>>>>>>>>>>>>> Can you be more precise what is this in addition to? How >> many total >> >>>>>>>>>> reviewers do you expect and what is the purpose of additional >> reviewer? and >> >>>>>>>>>> why? >> >>>>>>>>>>>>>>>> Taking a step back - what are you trying to solve here? >> >>>>>>>>>>>>>>>> Dinesh >> >>
