Why does my PR say “Build required for forked branch”?
Chromatic can’t find a build for the pull request’s head branch on the fork. UI Review needs that build to compare the branch with its base.
Run Chromatic on the fork’s head branch, then check the build’s commit SHA, branch name, and repository against the pull request. If the build exists but Chromatic still can’t find it, correct the Git context in CI. Set all three variables: CHROMATIC_SHA to the source branch’s head SHA, CHROMATIC_BRANCH to its branch name, and CHROMATIC_SLUG to the source (fork) repository’s owner/repo slug. See the provider variable table and Git options.
For GitHub Actions pull requests, use the pull request’s head SHA and branch rather than the temporary merge commit. Set CHROMATIC_SLUG to github.event.pull_request.head.repo.full_name. Use the target Chromatic project’s token for the build. Forked pull requests need a way to access that token. See Forked repositories.
If the branch has no build, see Why is the UI Review stuck in “Awaiting activity”? for other checks.