# Apply Pr To Flake

> Apply a nixpkgs PR override to the flake.nix configuration Use when this capability is needed.

- Skill: `tomevault-io/apply-pr-to-flake` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/apply-pr-to-flake`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/apply-pr-to-flake/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/apply-pr-to-flake

---


## What I do

Apply a nixpkgs PR to flake.nix by creating an input and overlay to override a specific package version. This follows the documented pattern in flake.nix lines 120-137.

## When to use me

Use this when you want to apply a PR from the main nixpkgs repository to override a package version in your flake without merging it upstream yet.

## Questions I'll ask

1. **PR number** - The pull request number (e.g., 500995)
2. **Repository** - Which nixpkgs repository to use (default: NixOS/nixpkgs)
3. **Package name** - Which nixpkgs package to override
4. **Input name** - Descriptive name for the input (e.g., pr500995, pr471984)
5. **Version check** - Should I verify the package version is not newer than a specific version? (default: null, no check)
   - If yes: Provide the maximum allowed version in semantic version format (e.g., "8401")
   - If no: Set to null to skip version checking
6. **Create module file** - Should I create `modules/pr-overlays.nix` for declarative management?
   - Yes: Creates a NixOS module with option `myconfig.prOverlays.enable` and list of overlays [{package, prNumber, inputName, maxVersion?, prUrl}]
   - No: Only modify flake.nix
   - Default: Yes for new setups

## Implementation steps

1. Get the PR commit hash by fetching PR details
2. Create the input in the `inputs` section after other inputs:
   ```
   {input}.url = "github:{owner}/{repo}/{commit-hash}";
   ```
3. Add the overlay in the PR patch section using the pattern:
   ```
   nixpkgs.overlays = map
     ({ input, pkg }:
     (_: _:
       { "${pkg}" =
         (import inputs."${input}" {
           inherit (pkgs) config system;
         })."${pkg}";
       })
     )
     [
       { input = "{input}"; pkg = "{package}"; }
     ];
   ```
4. Run `./nixfmtall.sh` to format all Nix files
5. Run `nix flake check` to validate the configuration

## Notes

- Follow the pattern exactly by placing the overlay module after the core system module and before other overlays
- Use descriptive input names: `pr<PR-number>` is preferred (e.g., pr500995)
- Comment out the URL in the template section for easy reference
- Always run `nix flake check` after making changes to ensure validity
- The overlay will only override the package; other packages remain from the main nixpkgs
- The entry should be placed near the other PR-related comments in the PR template section

---
> Source: [maxhbr/myconfig](https://github.com/maxhbr/myconfig) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-06-29 -->