I still dont get the idea about AI code reviews.
A code review (at least in my opinion) is for your peers to check if the changes will have a positive or negative effect on the overall code + architecture.
I have yet to see an LLM being good at this.
Sure, they will leave comments about common made errors (your editor should already warn about this before you even commit it) etc. But to notify about this weird thing that was done to make sure something a lot of customers wanted is made reality.
also, PR's are created to share knowledge. Questions and answers on them are to spread knowledge in the team. AI does not do that.
With not much more effort you can get a much better review by additionally concatenating the touched files and sending them as context along with the diff. It was the work of about five minutes to make the scaffolding of a very basic bot that does this, and then somewhat more time iterating on the prompt. By the way, I find it's seriously worth sucking up the extra ~four minutes of delay and going up to GPT-5 high rather than using a dumber model; I suspect xhigh is worth the ~5x additional bump in runtime on top of high, but at that point you have to start rearchitecting your workflows around it and I haven't solved that problem yet.
(That's if you don't want to go full Codex and have an agent play around with the PR. Personally I find that GPT-5.2 xhigh is incredibly good at analysing diffs-plus-context without tools.)
Do you do any preprocessing of diffs to replace significant whitespace with some token that is easier to spot? In my experience, some LLMs cannot tell unchanged context from the actual changes. That's especially annoying with -U99999 diffs as a shortcut to provide full file context.
I've been using gemini-3-flash the last few days and it is quite good, I'm not sure you need the biggest models anymore. I have only switched to pro once or twice the last few days
Depends what you mean by "need", of course, but in my experience the curves aren't bending yet; better model still means better-quality review (although GPT-5.0 high was still a reasonably competent reviewer)!
Hum? I just tell claude to review pr #123 and it uses 'gh' to do everything, including responding to human comments! Feedback from coleagues has been awesome.
Not my experience. Most Claude reviews are horrible and if I catch you replying with Claude (any AI really) under your own name you are gonna get two earfulls. Don't get me wrong, if you have an AI bot that I can have a convo with on the PR, sure. But you passing their stuff off as you: do that twice and you're dead to me.
Now, I use it as well to review, just like you mention it pulls it via gh, has all the source to reference and then tells me what it thinks. But it can't be left alone.
Similarly people have been trying to pass root cause analyses off as true and they sound confident but have holes like a good Swiss cheese.
Good thing I work on an old C++ code base where it's impossible for AI to go through the millions of lines that all interact horribly in unpredictable ways.
Funny you mention that, I have very recently just came back from a one-shot prompt which fixed a rather complex template instantiation issue in a relatively big very convoluted low-level codebase (lots of asm, SPDK / userspace nvme, unholy shuffling of data between numa domains into shared l3/l2 caches). That codebase maybe isn't in millions of lines of code but definitely is complex enough to need a month of onboarding time. Or you know, just give Claude Opus 4.5 a lldb backtrace with 70% symbols missing due to unholy linker gymnastics and get a working fix in 10 mins.
And those are the worst models we will have used from now on.
As for PR reviews, assuming you've got linting and static analysis out the way, you'd need to enter a sufficiently reasonable prompt to truly catch problems or surface reviews that match your standard and not generic AI comments.
My company uses some automatic AI PR review bots, and they annoy me more than they help. Lots of useless comments
I would just put a PR_REVIEW.md file in the repo an have a CI agent run it on the diff/repo and decide pass or reject. In this file there are rules the code must be evaluated against. It could be project level policy, you just put your constraints you cannot check by code testing. Of course any constraint that can be a code test, better be a code test.
My experience is you can trust any code that is well tested, human or AI generated. And you cannot trust any code that is not well tested (what I call "vibe tested"). But some constraints need to be in natural language, and for that you need a LLM to review the PRs. This combination of code tests and LLM review should be able to ensure reliable AI coding. If it does not, iterate on your PR rules and on tests.
`gh pr diff num` is an alternative if you have the repo checked out. One can then pipe the output to one's favorite llm CLI and create a shell alias with a default review prompt.
> My company uses some automatic AI PR review bots, and they annoy me more than they help. Lots of useless comments
One way to make them more useful is to ask to list the topN problems found in the change set.
while this approach is useful, i think the diff is too small to catch a lot of bugs.
i use https://www.coderabbit.ai/ and it tends to be aware of files that aren't in the diff, and definitely can see the rest of the file your are editing (not just the lines in the diff)
I recently started using LLMs to review my code before asking for a more formal review from colleagues. It's actually been surprisingly useful - why waste my colleagues time with small obvious things? But it's also gone much further than that sometimes with deeper reviews points. Even when I don't agree with them it's great having that little bit more food for thought - if anything it helps seed the review
"Diff to master and review the changes. Branch designed to address <problem statement>. Write output to d:\claudeOut in typst (.typ) format."
It'll do the diffs and search both branch and master versions of files.
I prefer reading PDFs than markdown, but it'll default to markdown unprompted if you prefer.
I have almost all my workspaces configured with /add-dir to add d:/claudeOut and d:/claudeIn as general scratch folders for temporary in/out file permissions so it can read/write outside the context of the workspace for things like this.
You might get better results using a better crafted prompt (or code review skill?). In general I find claude code reviews are:
- Overly fussy about null checking everything
- Completely miss on whether the PR has properly distilled the problem down to its essence
- Are good at catching spelling mistakes
- Like to pretend they know if something is well architectured, but doesn't
So it's a bit of a mixed bag, I find it focuses on trivia but it's still useful as a first pass before letting your teammates have to catch that same trivia.
It will absolutely assume too much from naming, so it's kind of a good spot if it's making wrong kind of assumptions about how parts work, to think how to name things more clearly.
e.g. If you write a class called "AddingFactory", it'll go around assuming that's what it does, even if the core of it returns (a, b) -> a*b.
You have to then work hard to get it to properly examine the file and convince itself that it is actually a multiplier.
Obviously real-world examples are more subtle than that, but if you're finding yourself arguing with it, it's worth sometimes considering whether you should rename things.
This one's served fairly well:
"Review this diff - detect top 10 problem-causers, highlight 3 worst - I'm talking bugs with editing,saving etc. (not type errors or other minor aspects) [your diff]". The bit on "editing, saving" would vary based on goal of diff.
We're a Haskell shop, so I usually just say "review the current commit. You're an experienced Haskell programmer and you value readable and obvious code" (because that it is indeed what we value on the team). I'll often ask it to explicitly consider testing, too
Not who you're replying to but working at a small small company, I didn't have anyone to give my code for review to so have used AI to fill in that gap. I usually go with a specific then general pass, where for example if I'm making heavy use of async logic, I'll ask the LLM to pay particular attention to pitfalls that can arise with it.
I have been using Codex as a code review step and it has been magnificent, truly. I don’t like how it writes code, but as a second line of defence I’m getting better code reviews out of it than I’ve ever had from a human.
I still dont get the idea about AI code reviews. A code review (at least in my opinion) is for your peers to check if the changes will have a positive or negative effect on the overall code + architecture. I have yet to see an LLM being good at this.
Sure, they will leave comments about common made errors (your editor should already warn about this before you even commit it) etc. But to notify about this weird thing that was done to make sure something a lot of customers wanted is made reality.
also, PR's are created to share knowledge. Questions and answers on them are to spread knowledge in the team. AI does not do that.
[edit] Added the part about knowledge sharing
With not much more effort you can get a much better review by additionally concatenating the touched files and sending them as context along with the diff. It was the work of about five minutes to make the scaffolding of a very basic bot that does this, and then somewhat more time iterating on the prompt. By the way, I find it's seriously worth sucking up the extra ~four minutes of delay and going up to GPT-5 high rather than using a dumber model; I suspect xhigh is worth the ~5x additional bump in runtime on top of high, but at that point you have to start rearchitecting your workflows around it and I haven't solved that problem yet.
(That's if you don't want to go full Codex and have an agent play around with the PR. Personally I find that GPT-5.2 xhigh is incredibly good at analysing diffs-plus-context without tools.)
Do you do any preprocessing of diffs to replace significant whitespace with some token that is easier to spot? In my experience, some LLMs cannot tell unchanged context from the actual changes. That's especially annoying with -U99999 diffs as a shortcut to provide full file context.
I've been using gemini-3-flash the last few days and it is quite good, I'm not sure you need the biggest models anymore. I have only switched to pro once or twice the last few days
Here are the commits, the tasks were not trivial
https://github.com/hofstadter-io/hof/commits/_next/
Social posts and pretty pictures as I work on my custom copilot replacement
https://bsky.app/profile/verdverm.com
Depends what you mean by "need", of course, but in my experience the curves aren't bending yet; better model still means better-quality review (although GPT-5.0 high was still a reasonably competent reviewer)!
Yes, it's my new daily driver for light coding and the rest. Also great at object recognition and image gen
Hum? I just tell claude to review pr #123 and it uses 'gh' to do everything, including responding to human comments! Feedback from coleagues has been awesome.
We are sooo gonna get replaced soon...
Not my experience. Most Claude reviews are horrible and if I catch you replying with Claude (any AI really) under your own name you are gonna get two earfulls. Don't get me wrong, if you have an AI bot that I can have a convo with on the PR, sure. But you passing their stuff off as you: do that twice and you're dead to me.
Now, I use it as well to review, just like you mention it pulls it via gh, has all the source to reference and then tells me what it thinks. But it can't be left alone.
Similarly people have been trying to pass root cause analyses off as true and they sound confident but have holes like a good Swiss cheese.
> Feedback from colleagues has been awesome
Colleague's feedback:
Claude> Address comments on PR #123
Good thing I work on an old C++ code base where it's impossible for AI to go through the millions of lines that all interact horribly in unpredictable ways.
Funny you mention that, I have very recently just came back from a one-shot prompt which fixed a rather complex template instantiation issue in a relatively big very convoluted low-level codebase (lots of asm, SPDK / userspace nvme, unholy shuffling of data between numa domains into shared l3/l2 caches). That codebase maybe isn't in millions of lines of code but definitely is complex enough to need a month of onboarding time. Or you know, just give Claude Opus 4.5 a lldb backtrace with 70% symbols missing due to unholy linker gymnastics and get a working fix in 10 mins.
And those are the worst models we will have used from now on.
TIL: you could add a ".diff" to a PR URL. Thanks!
As for PR reviews, assuming you've got linting and static analysis out the way, you'd need to enter a sufficiently reasonable prompt to truly catch problems or surface reviews that match your standard and not generic AI comments.
My company uses some automatic AI PR review bots, and they annoy me more than they help. Lots of useless comments
I would just put a PR_REVIEW.md file in the repo an have a CI agent run it on the diff/repo and decide pass or reject. In this file there are rules the code must be evaluated against. It could be project level policy, you just put your constraints you cannot check by code testing. Of course any constraint that can be a code test, better be a code test.
My experience is you can trust any code that is well tested, human or AI generated. And you cannot trust any code that is not well tested (what I call "vibe tested"). But some constraints need to be in natural language, and for that you need a LLM to review the PRs. This combination of code tests and LLM review should be able to ensure reliable AI coding. If it does not, iterate on your PR rules and on tests.
`gh pr diff num` is an alternative if you have the repo checked out. One can then pipe the output to one's favorite llm CLI and create a shell alias with a default review prompt.
> My company uses some automatic AI PR review bots, and they annoy me more than they help. Lots of useless comments
One way to make them more useful is to ask to list the topN problems found in the change set.
> TIL: you could add a ".diff" to a PR URL. Thanks!
You can also append ".patch" and get a more useful output
https://cursor.com/bugbot
I didn't see this mentioned, but we've been running bugbot for a while now and it's very good. It catches so many subtle bugs.
while this approach is useful, i think the diff is too small to catch a lot of bugs.
i use https://www.coderabbit.ai/ and it tends to be aware of files that aren't in the diff, and definitely can see the rest of the file your are editing (not just the lines in the diff)
In CC or Codex (or whichever) — “run git diff and review”
I recently started using LLMs to review my code before asking for a more formal review from colleagues. It's actually been surprisingly useful - why waste my colleagues time with small obvious things? But it's also gone much further than that sometimes with deeper reviews points. Even when I don't agree with them it's great having that little bit more food for thought - if anything it helps seed the review
Are you using a particularly well crafted prompt or just something off the cuff?
Personally, this is what I use in claude code:
"Diff to master and review the changes. Branch designed to address <problem statement>. Write output to d:\claudeOut in typst (.typ) format."
It'll do the diffs and search both branch and master versions of files.
I prefer reading PDFs than markdown, but it'll default to markdown unprompted if you prefer.
I have almost all my workspaces configured with /add-dir to add d:/claudeOut and d:/claudeIn as general scratch folders for temporary in/out file permissions so it can read/write outside the context of the workspace for things like this.
You might get better results using a better crafted prompt (or code review skill?). In general I find claude code reviews are:
So it's a bit of a mixed bag, I find it focuses on trivia but it's still useful as a first pass before letting your teammates have to catch that same trivia.It will absolutely assume too much from naming, so it's kind of a good spot if it's making wrong kind of assumptions about how parts work, to think how to name things more clearly.
e.g. If you write a class called "AddingFactory", it'll go around assuming that's what it does, even if the core of it returns (a, b) -> a*b.
You have to then work hard to get it to properly examine the file and convince itself that it is actually a multiplier.
Obviously real-world examples are more subtle than that, but if you're finding yourself arguing with it, it's worth sometimes considering whether you should rename things.
This one's served fairly well: "Review this diff - detect top 10 problem-causers, highlight 3 worst - I'm talking bugs with editing,saving etc. (not type errors or other minor aspects) [your diff]". The bit on "editing, saving" would vary based on goal of diff.
We're a Haskell shop, so I usually just say "review the current commit. You're an experienced Haskell programmer and you value readable and obvious code" (because that it is indeed what we value on the team). I'll often ask it to explicitly consider testing, too
Not who you're replying to but working at a small small company, I didn't have anyone to give my code for review to so have used AI to fill in that gap. I usually go with a specific then general pass, where for example if I'm making heavy use of async logic, I'll ask the LLM to pay particular attention to pitfalls that can arise with it.
This is exactly the right approach IMO. You find the signal amongst the slop, and all your colleagues see is a better PR.
I have been using Codex as a code review step and it has been magnificent, truly. I don’t like how it writes code, but as a second line of defence I’m getting better code reviews out of it than I’ve ever had from a human.
How to do agentic workflow like 2 years ago.
What would SOA be?