Inspected the installed GitHub CLI at /opt/homebrew/bin/gh; Homebrew had installed version 2.97.0, which does not expose --attach on pull request commands.
Verified from the GitHub CLI 2.99.0 release, official attachment documentation, upstream source, and the official macOS arm64 binary that 2.99.0 is the minimum release with --attach.
Confirmed that an updated Homebrew formula and conda-forge both provide version 2.99.0 on this macOS system.
Provided exact gh pr edit 368 --repo virdx/mono --attach '<path>#<alt text>' commands for appending PNG screenshots to the pull request description while preserving its body, plus the gh pr comment alternative.
Documented supported media formats, image size and batch limits, alt-text behavior, host support, and the repository write-access requirement.
Homebrew’s formula metadata initially reported 2.98.0 until brew update; checking installed and available versions without refreshing can incorrectly suggest that the required release is unavailable.
Installing the Pixi package alone would not change plain gh resolution on this machine because /opt/homebrew/bin precedes ~/.pixi/bin in PATH.
The feature name can imply arbitrary file upload, but version 2.99.0 only accepts supported images and videos.
Lessons Learned: Improvements
A short infrastructure note about GitHub CLI tool ownership and PATH order would make future CLI upgrade choices faster.
PR screenshot guidance should state that gh pr edit --attach updates the description without replacing the existing body when no body flag is supplied.
