Show HN: A local merge queue for parallel Claude Code agents (github.com)
I have been pushing up to 90 commits a day on a MacBook Air via 4-5 parallel agents. As you can imagine when all the agents try to build, test and run dev servers on an 8GB machine it is the fast lane to a force quit and restart. I also did not want to pay the CI minutes on 90 pushes a day.
So I designed a local merge queue to have all commits land one at a time and fully tested. Hopefully this helps other folks with more modest machines. Appreciate any feedback.
20 comments
[ 2.0 ms ] story [ 28.1 ms ] threadI'm having a much better time with jj and a workspace per subagent than I was with git and worktrees.
It's still useful to have the CI gating on updating the master branch pointer, but you largely stop working with branches once you switch to jj.
I just built something pretty much in the same vein of this with Claude over the past 2 months. It's a custom deployment system that uses work trees and each work tree has to to run end-to-end tests (Playright, Supabase, Astro) and other tests and create a stamp based on the contents of the entire tree. And then if another work tree has the same digest that matches the stamp then it can bypass the tests. So nothing can land on main without tests passing. Which is all in in enforced with a pre-push hook that checks the digest.
Then once it's on main it is deployed to Dev and then from there it can be promoted to prod.
I like the idea of just having one branch and the work trees funnel into it.
But definitely going to have my setup analyze this and see what can be improved with it or if I should just throw out mine and use that one.
I understand each commit might have different size, but I am guessing your commits == Pull Request (because you need this constant merge queue to rebase, merge, test) and each are around 40-80 lines of code (additions and removals), and you are probably not reviewing the code because at this rate even if one commit takes 2 minutes to review we are talking about 3 hours of non stop code review.
if you are not reviewing each code, probably your commits are small items and 10-20 of them are a part of single PR, then how do you sustain working across multiple projects?
I have local test suite of unit / arch / e2e / build / lint / tsc when it merges to dev. Then the same suite runs on a merge to main which pushes to prod. I have post main-push e2e that checks for regressions and automatically rolls back.
Each suite run takes 3-4 minutes so I can usually push through 15 or so commits an hour fully tested and cleanly.
I do not use PRs with this workflow, and if something breaks I add tests to prevent it happening again rather than altering the setup.
Most of the commits are for a side project (https://hola.career/) so I afford to a bit more loose than I would in professional capacity.
I have not used this on a team, and what you would end up with is likely a giant PR with all those local commits that no one wants to review. Eventually someone might hold their nose and press the approve button. But that would probably be the end of the package at that workplace.
This is optimized for one engineer that does not have the machine capacity to run multiple lanes of their check test suites locally at once and also does want to pay for GHA minutes on a free plan to run those suites in the cloud.
your force quitting is probably more from your build pipeline than anything agents are doing.
i use an m2 8gb air with no performance issues at up to 10 parallel claude code interactive sessions (ghostty), each with deep/transient subagent heirarchies that mix claude and codex.
very rarely need to force quit. only seen a couple restart-level failures, and those were on me for being cowboy with subagent delegation logic, resulting in 100s of claude moles popping up faster than i could whack them with force close.
I tell each thread to name itself with a prefix and it's picked up by a merge queue thread which instructs them merge one at a time. Each thread has to look at the main ref as it's changed since they did their work and determine what kind of merge needs to happen. To safely merge a a variety of merge types I have a commit skill which details the process for forward reconstruction, for example.
As of yesterday I have a single voice orchestrator thread which then can poke other threads as well as the merge queue thread.
Sometimes I just do stuff in working copy when I know exactly where in the history it's going to land (I rewrite history extensively to know cleanly where that it) and I'll git absorb / jj absorb it manually.