headroom: init at 0.41.0 by attilaolah · Pull Request #569784 · NixOS/nixpkgs

attilaolah · 2026-10-03T12:35:17Z

Add Headroom. Can be used both as a proxy via headroom proxy and as an MCP via headroom mcp serve.

The original attempt at packaging Headroom was in #529964, thanks for the inspiration.

Things done

Wrap it with the necessary tools to avoid binary downloads at runtime
Fetch Tiktoken encodings into the Nix store to prevent Headroom from fetching them on-the-fly
Try to get as much of the tests to run as I could

attilaolah · 2026-10-03T14:03:49Z

This should be ready for review now. I've been using this package for a little over a month now, on both NixOS and Darwin, both as a proxy and as an MCP server. So far no issues.

attilaolah · 2026-10-03T14:06:04Z

@SuperSandro2000 you said in #529964 (comment) you might pick up Headroom, maybe you have some input here.

attilaolah · 2026-10-05T07:39:42Z

@GraysonTinker I added you since you've already looked at #529964, but feel free to suggest someone else.

GraysonTinker · 2026-10-05T08:06:55Z

Will do when I get the chance, ouch that's a long derivation

attilaolah · 2026-10-05T08:33:51Z

Thanks, and no rush at all. It is long indeed, much if it is about forcing the tests into the sandbox though…

SuperSandro2000

I never got to the tests and then got distracted, but I prepared all the dependencies

attilaolah · 2026-10-05T11:31:53Z

Looks like there are dynamic imports or similar in the tests, so a plain rm -rf headroom is not going to be enough.

attilaolah · 2026-10-12T05:56:46Z

The move from python3Packages to top-level broke the headroom proxy command which re-execs Python and requires re-importing the headroom package.

Let me fix & verify that.

This fails on Darwin, but works on Linux:

nix run github:NixOS/nixpkgs/fc8c84a279555a6ce7f4f916bd4a17ffed224c9a#headroom -- proxy

attilaolah · 2026-10-12T06:35:24Z

The issue appears to be that Headroom on Darwin re-exec's Python to get a more efficient malloc, merged in headroomlabs-ai/headroom#2879.

On Linux this path is never taken so the binary executes normally. On Darwin, the re-exec fails due to $out remaining literal in the wrapper script, which I think was due to a missing ${placeholder "out"}.

I'm testing a fix now.

attilaolah · 2026-10-12T08:42:39Z

Confirmed b3dc24c, headroom proxy works on both Linux and macOS now.

attilaolah · 2026-10-16T20:06:48Z

Version 0.41.0 is now out, I am testing it locally, will update this PR once confirmed working on Linux & Darwin.

Or, if merged in the meantime, then will post it as a normal update.

attilaolah · 2026-10-16T23:35:54Z

PR rebased & updated to 0.41.0.

Tested the new build on Linux, will test on Darwin when the build completes
This new version requires an additional patch to restore a module vs. exported name collision

This name collision apparently doesn't happen in Python 3.12, which is what upstream tests against. There are some efforts upstream to test against Python 3.14, but I'm not sure about the progress.

The targeted Pytest fixture patch allows tests to pass. The runtime issue is still present, but is import-order dependent, and as long as the normal headroom CLI doesn't trigger the "wrong" import order, it seems to be working fine.

attilaolah · 2026-10-17T10:05:51Z

5 new failures on Darwin, am working on those now
2 previously deselected tests are no longer present upstream, cleanup coming soon

attilaolah · 2026-10-17T12:24:52Z

`nixpkgs-review` result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 569784
Commit: bbf61c790b44abe65be9c60665cfb0fa28f25767

`aarch64-darwin`

✅ 1 package built:

headroom

attilaolah · 2026-10-17T13:09:17Z

`nixpkgs-review` result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 569784
Commit: bbf61c790b44abe65be9c60665cfb0fa28f25767

`x86_64-linux`

✅ 1 package built:

headroom

attilaolah · 2026-10-25T14:17:08Z

This is now broken since #575004. I'll attempt a fix, following the example in #578535.

https://github.com/headroomlabs-ai/headroom/releases/tag/v0.41.0 Assisted-by: OpenCode (GPT 5.6 Terra) Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

attilaolah · 2026-10-25T14:42:00Z

Should be fixed now. Headroom pins mcp < 2 so I added the necessary scope override.

attilaolah · 2026-10-25T15:16:21Z

`nixpkgs-review` result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 569784
Commit: 17532b74898e31f81b09adc0645814569fdaf3c3

`aarch64-darwin`

✅ 1 package built:

headroom

attilaolah · 2026-10-25T16:08:55Z

`nixpkgs-review` result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 569784
Commit: 17532b74898e31f81b09adc0645814569fdaf3c3

`x86_64-linux`

✅ 1 package built:

headroom

attilaolah force-pushed the headroom-ai branch from 0d9c2cd to 46dd15e Compare October 3, 2026 12:41

nixpkgs-ci Bot added the 6.topic: python Python is a high-level, general-purpose programming language. label Oct 3, 2026

attilaolah force-pushed the headroom-ai branch from 46dd15e to 80ccc90 Compare October 3, 2026 12:46

This comment was marked as outdated.

Sign in to view

attilaolah marked this pull request as ready for review October 3, 2026 14:03

attilaolah force-pushed the headroom-ai branch from 80ccc90 to 76603f6 Compare October 3, 2026 14:09

nixpkgs-ci Bot added 9.needs: reviewer This PR currently has no reviewers requested and needs attention. 7.no default reviewers This PR targets a package or module with no existing maintainers; roving reviewers, take pity! labels Oct 3, 2026

attilaolah requested a review from GraysonTinker October 5, 2026 07:37

nixpkgs-ci Bot removed the 9.needs: reviewer This PR currently has no reviewers requested and needs attention. label Oct 5, 2026

SuperSandro2000 reviewed Oct 5, 2026

View reviewed changes

This comment was marked as outdated.

Sign in to view

attilaolah force-pushed the headroom-ai branch 4 times, most recently from e890ec2 to 81ac7cd Compare October 5, 2026 11:15

This comment was marked as outdated.

Sign in to view

attilaolah force-pushed the headroom-ai branch from 81ac7cd to 09265aa Compare October 5, 2026 11:39

This comment was marked as outdated.

Sign in to view

nixpkgs-ci Bot added 10.rebuild-linux: 1 This PR causes 1 package to rebuild on Linux. and removed 6.topic: python Python is a high-level, general-purpose programming language. labels Oct 9, 2026

This comment was marked as outdated.

Sign in to view

attilaolah marked this pull request as draft October 12, 2026 05:56

attilaolah force-pushed the headroom-ai branch from fc8c84a to b3dc24c Compare October 12, 2026 06:37

attilaolah marked this pull request as ready for review October 12, 2026 08:42

This comment was marked as outdated.

Sign in to view

attilaolah force-pushed the headroom-ai branch from b3dc24c to aaaf275 Compare October 16, 2026 23:31

attilaolah changed the title ~~headroom: init at 0.40.0~~ headroom: init at 0.41.0 Oct 16, 2026

attilaolah force-pushed the headroom-ai branch from aaaf275 to 7ef9e5f Compare October 16, 2026 23:36

This comment was marked as outdated.

Sign in to view

attilaolah force-pushed the headroom-ai branch 2 times, most recently from 5657b95 to bbf61c7 Compare October 17, 2026 12:17

headroom: init at 0.41.0

17532b7

https://github.com/headroomlabs-ai/headroom/releases/tag/v0.41.0 Assisted-by: OpenCode (GPT 5.6 Terra) Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

attilaolah force-pushed the headroom-ai branch from bbf61c7 to 17532b7 Compare October 25, 2026 14:35

Conversation

attilaolah commented Oct 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Things done

Uh oh!

This comment was marked as outdated.

This comment was marked as outdated.

attilaolah commented Oct 3, 2026

Uh oh!

attilaolah commented Oct 3, 2026

Uh oh!

attilaolah commented Oct 5, 2026

Uh oh!

GraysonTinker commented Oct 5, 2026

Uh oh!

attilaolah commented Oct 5, 2026

Uh oh!

SuperSandro2000 left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

This comment was marked as outdated.

This comment was marked as outdated.

attilaolah commented Oct 5, 2026

Uh oh!

This comment was marked as outdated.

This comment was marked as outdated.

This comment was marked as outdated.

attilaolah commented Oct 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

attilaolah commented Oct 12, 2026

Uh oh!

attilaolah commented Oct 12, 2026

Uh oh!

This comment was marked as outdated.

This comment was marked as outdated.

attilaolah commented Oct 16, 2026

Uh oh!

attilaolah commented Oct 16, 2026

Uh oh!

This comment was marked as outdated.

This comment was marked as outdated.

attilaolah commented Oct 17, 2026

Uh oh!

attilaolah commented Oct 17, 2026

nixpkgs-review result

aarch64-darwin

Uh oh!

attilaolah commented Oct 17, 2026

nixpkgs-review result

x86_64-linux

Uh oh!

attilaolah commented Oct 25, 2026

Uh oh!

attilaolah commented Oct 25, 2026

Uh oh!

attilaolah commented Oct 25, 2026

nixpkgs-review result

aarch64-darwin

Uh oh!

attilaolah commented Oct 25, 2026

nixpkgs-review result

x86_64-linux

Uh oh!

Reviewers

Uh oh!

Assignees

Labels

Projects

Milestone

Development

Uh oh!

attilaolah commented Oct 3, 2026 •

edited

Loading

attilaolah commented Oct 12, 2026 •

edited

Loading

`nixpkgs-review` result

`aarch64-darwin`

`nixpkgs-review` result

`x86_64-linux`

`nixpkgs-review` result

`aarch64-darwin`

`nixpkgs-review` result

`x86_64-linux`