diff --git a/scripts/setup/machine-setup/lib/packages.sh b/scripts/setup/machine-setup/lib/packages.sh
index aaa7b5c4..936de3e4 100644
--- a/scripts/setup/machine-setup/lib/packages.sh
+++ b/scripts/setup/machine-setup/lib/packages.sh
@@ -125,7 +125,14 @@ pkgs_core() {
       # curl, unzip and the TLS roots ship with macOS; the compilers come from
       # the Xcode command line tools, which is not a formula — see xcode_clt_*.
       # brotli is here because macOS ships the library but not the CLI.
-      echo gnupg git jq wget brotli btop htop tree ripgrep fd eza poppler radicale
+      #
+      # radicale has no Homebrew formula — confirmed live ("No available formula with the
+      # name radicale"), it is a pure-Python package normally installed via pip/pipx, not
+      # brew. Left out of a dev install rather than reached for pip here: officer-caldav
+      # (services.sh CORE_PROCESSES) is skipped to match on macOS, so nothing on this
+      # machine expects it to be present. The Linux lists above are untouched — a real
+      # package there, unaffected.
+      echo gnupg git jq wget brotli btop htop tree ripgrep fd eza poppler
       ;;
   esac
 }
diff --git a/scripts/setup/officer-setup/lib/services.sh b/scripts/setup/officer-setup/lib/services.sh
index 7fcbc75c..d2499fb5 100644
--- a/scripts/setup/officer-setup/lib/services.sh
+++ b/scripts/setup/officer-setup/lib/services.sh
@@ -44,13 +44,6 @@ CORE_PROCESSES=(
   "officer-claude-code|bun|run src/servers/sidecar/claude/user-instance.ts"
   "officer-opencode|bun|run src/servers/sidecar/opencode/index.ts"
   "officer-pty|node|src/servers/sidecar/pty/index.mjs"
-  # Calendar and contacts, CORE since 2026-08-19 rather than an app-store entry.
-  #
-  # It was a Docker service because the app store made everything one, not because Radicale needs a
-  # container — it is a ~2MB Python package, and this sidecar spawns it directly on loopback. A personal
-  # server having a calendar is not an integration with something you already run; it is the baseline.
-  # Radicale needs `python3` and the `radicale` package, both installed by machine-setup.
-  "officer-caldav|bun|run src/servers/sidecar/caldav/index.ts"
   # Push notifications, CORE since 2026-08-19. Built 2026-07-31, then switched off on 2026-08-13 with
   # memos and photos when it was slated to become a plugin — the only one of the three never extracted,
   # so it sat mounted nowhere with its schema commented out.
@@ -62,6 +55,21 @@ CORE_PROCESSES=(
   "officer-notify|bun|run src/servers/sidecar/notify/index.ts"
 )
 
+# Calendar and contacts, CORE since 2026-08-19 rather than an app-store entry.
+#
+# It was a Docker service because the app store made everything one, not because Radicale needs a
+# container — it is a ~2MB Python package, and this sidecar spawns it directly on loopback. A personal
+# server having a calendar is not an integration with something you already run; it is the baseline.
+# Radicale needs `python3` and the `radicale` package, both installed by machine-setup.
+#
+# EXCEPT on macOS: radicale has no Homebrew formula (pkgs_core in machine-setup/lib/packages.sh
+# leaves it out of the brew list for the same reason), so a dev install has nowhere for this sidecar
+# to find it — `resolveRadicale()` failing is exactly the "took a whole sidecar down on a fresh
+# install" case its own test guards against. Left out of a macOS install's process list entirely
+# rather than crash-looped; Calendar/Contacts are the one core feature not available on a Mac dev
+# install. The Linux path — and the feature itself — is untouched.
+[[ "$(uname -s)" == "Darwin" ]] || CORE_PROCESSES+=("officer-caldav|bun|run src/servers/sidecar/caldav/index.ts")
+
 write_ecosystem() {
   local dest entry name script args
   dest="$(ecosystem_file)"