The mcp-server-diff action checks the baseline ref out into a separate
working directory and runs install_command there. Without prebuilt UI
artifacts, pkg/github/ui_dist/ is empty on the baseline side and
UIAssetsAvailable() returns false, producing a false-positive diff that
"adds" _meta.ui to MCP Apps tools on every PR.
Stash the artifacts to RUNNER_TEMP after the workflow's build-ui step,
then restore them from install_command so both the baseline and PR
checkouts register identical MCP Apps UI metadata.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Sam Morrow
0b644d7b74