Thanks for all the feedback, everyone!

Regarding the choice of channel, how about I upload the reviews as
snippets to e.g.
https://gitlab.haskell.org/sjakobi/llm-reviews/-/snippets/? The
advantage of snippets is that people can comment on them, so I can
easily collect feedback on the quality of the reviews.

It's important to me though that there is some visible connection from
the MR to the review:

1. The information in the review is intended for all people who are
involved in an MR: Both authors and reviewers.
2. Similarly, I'd really love to get feedback from everyone who cares
to read the reviews. This way I can improve the service more quickly.
3. I want some visibility, so more people are likely to give the service a try.

In case you're worried about your AI agents ingesting the generated
reviews, I think it shouldn't be too hard to block access to that repo
for them.

In other news, Anthropic has generously accepted my application for
their open source program
(https://claude.com/contact-sales/claude-for-oss), so for the next 6
months, I do have a decent amount of usage that I can spend on reviews
(including access to Fable 5!).

Consequently, I have started vibe-coding a primitive "mini-sashiko"
for GHC: GlaHiCo
(https://gitlab.haskell.org/sjakobi/GlaHiCo/-/merge_requests/1). Right
now there's just a single "finder" agent, and each finding gets
checked separately by a "verifier" agent.

The code is a mess already of course, but it's slowly getting useful
too. If you have a feature request or want to contribute in other
ways, please let me know! :)

Cheers,
Simon




Am Mo., 27. Juli 2026 um 19:38 Uhr schrieb Simon Jakobi
<[email protected]>:
>
> Hi devs!
>
> Inspired by the recent discussion on the LLM policy, I'd like to try
> introducing LLM-generated code reviews in GHC, as an opt-in service.
>
> My motivation:
>
> * Catch issues before human reviewers spend time on them.
> * Reduce the number of bugs merged.
>
>
> What this is — and what it isn't
> --------------------------------
>
> This is tool output: requested on the MR, produced by a model, posted verbatim
> and clearly marked as machine-generated. This is not a review in the sense of
> draft LLM policy.
>
> I'm not vouching for any of it. Think of it as a linter the author could have
> run themselves, except on my LLM budget. Nobody is required to act on
> it even read it.
>
> I mention this explicitly because the policy asks reviewers to take full
> responsibility for each line of their review. I can't do that here — it would
> mean checking every finding myself, which defeats the purpose and would
> restrict the service to areas of the compiler I already know well.
>
>
> How to request one
> ------------------
>
> * Ping me on the MR with a comment like "@sjakobi llm-review please".
>   * Feel free to request particular aspects the review should cover.
> * Authors can request a review for their own MRs. Maintainers can request one
>   on any MR.
> * If I have enough usage left on my plan, I'll confirm that I'm on it.
> * I'll then prompt the model, and post the result on the MR.
> * Feedback on the quality of the review is of course very welcome.
>
>
> What I promise
> --------------
>
> * Every review is labelled as machine-generated, with model, effort level and
>   the exact prompt used.
> * Reviews are posted verbatim. I don't edit or curate them, so what you see is
>   exactly what the model produced.
> * Only the public MR diff and public repository context go to the model.
>   Nothing else.
> * I'll keep working on the prompts and the choice of model to improve the
>   signal-to-noise ratio.
> * If the signal-to-noise ratio stays inacceptably bad, we can simply
> stop this service.
>
>
> Review coverage
> ---------------
>
> I'll probably start with a fairly basic review prompt, primarily aimed at
> correctness issues.
>
> Possible extensions:
>
> * Documentation consistency: check that documentation stays consistent,
>   including Notes elsewhere that reference the changed code.
> * Performance: check for performance issues — potentially including checking
>   the -ddump-simpl output for the changed code for unnecessary
>   allocation etc.
> * Feel free to suggest anything else!
>
>
> Format
> ------
>
> Initially a single comment per review. Once we reach a good signal-to-noise
> ratio, we can consider inline comments on the diff.
>
>
> Caveats
> -------
>
> This is a volunteer service I intend to provide in my spare time. If I'm AFK
> or on vacation, reviews will take longer. If I can't keep up with requests, I
> will prioritise which MRs I run. I might take a break entirely.
>
>
> Getting involved
> ----------------
>
> Is anyone interested in joining this effort? If so we could form a team
> (@llm-reviewers?), and share prompting techniques, model choices, etc.
>
> If the service turns out to be genuinely useful, we can look into
> automating it and – if necessary – possible funding.
>
>
> Cheers,
> Simon
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