diff --git a/packages/desktop/README.md b/packages/desktop/README.md
index cf7e1c17..b5259e81 100644
--- a/packages/desktop/README.md
+++ b/packages/desktop/README.md
@@ -213,10 +213,12 @@ and the Dock icon bounces.
   Anyway* in System Settings > Privacy & Security (it asks for an administrator
   password). On macOS 14 and earlier, right-click it and choose *Open* once.
   Either way, `xattr -dr com.apple.quarantine /Applications/Codeman.app` on the
-  copy in Applications works too. Shipping it to other people needs a Developer
-  ID signature and notarization:
-  `SIGN_IDENTITY="Developer ID Application: ..." ./scripts/bundle-macos.sh --dmg`,
-  then `xcrun notarytool submit` and `xcrun stapler staple`.
+  copy in Applications works too. The `Codeman.dmg` on each GitHub release is
+  signed with a Developer ID and notarized by CI
+  (`.github/workflows/desktop-dmg.yml`), so it skips all of this. To do the
+  same by hand:
+  `SIGN_IDENTITY="Developer ID Application: ..." NOTARY_PROFILE=<profile> ./scripts/bundle-macos.sh --universal --notarize`,
+  where `scripts/sign-macos.sh` lists what it needs.
 - **Local Network permission (macOS 15 and later).** The first connection to an
   address on the local network (a LAN IP, a `.local` name) makes macOS ask
   whether Codeman may use the local network, and that first attempt can fail
@@ -278,4 +280,4 @@ and the Dock icon bounces.
 - Trusting a self-signed server certificate by its fingerprint.
 - Asking before a download that a rendered HTML file or a web tab starts.
 - A way out of a page that keeps opening dialogs (a "block further dialogs" option).
-- Windows and Linux builds, a CI job that builds the `.dmg`, notarization, auto-update.
+- Windows and Linux builds, auto-update.
diff --git a/packages/desktop/scripts/bundle-macos.sh b/packages/desktop/scripts/bundle-macos.sh
index ac1b5e6d..6fbdabdf 100755
--- a/packages/desktop/scripts/bundle-macos.sh
+++ b/packages/desktop/scripts/bundle-macos.sh
@@ -4,6 +4,8 @@
 #   packages/desktop/scripts/bundle-macos.sh            # this Mac's architecture
 #   packages/desktop/scripts/bundle-macos.sh --universal --dmg
 #   SIGN_IDENTITY="Developer ID Application: ..." packages/desktop/scripts/bundle-macos.sh --dmg
+#   SIGN_IDENTITY="Developer ID Application: ..." NOTARY_PROFILE=<profile> \
+#     packages/desktop/scripts/bundle-macos.sh --universal --notarize
 #
 # Without SIGN_IDENTITY the app is signed ad hoc: it runs on the Mac that built
 # it, and a copy downloaded on another Mac is stopped by Gatekeeper. On macOS 15
@@ -11,6 +13,15 @@
 # Privacy & Security; on macOS 14 and earlier, right-click it and choose Open.
 # Or run `xattr -dr com.apple.quarantine /Applications/Codeman.app` on the copy
 # in /Applications. A Developer ID signature + notarization avoids all of this.
+#
+# --dmg writes dist/Codeman-<version>.dmg, signed with SIGN_IDENTITY when it is
+# set. --notarize hands the built app to scripts/sign-macos.sh, which signs it
+# with SIGN_IDENTITY, has Apple notarize it, staples the ticket to it and does
+# the same for dist/Codeman.dmg, the DMG built around it (so --dmg is implied).
+# sign-macos.sh's header lists what it needs: SIGN_IDENTITY, and NOTARY_PROFILE
+# or APPLE_ID, APPLE_APP_PASSWORD and APPLE_TEAM_ID. The release workflow
+# (.github/workflows/desktop-dmg.yml) runs this script ad hoc in one job and
+# sign-macos.sh in another, so the job that runs cargo holds no secret.
 set -euo pipefail
 
 cd "$(dirname "$0")/.."
@@ -18,14 +29,21 @@ cd "$(dirname "$0")/.."
 
 UNIVERSAL=0
 DMG=0
+NOTARIZE=0
 for arg in "$@"; do
   case "$arg" in
     --universal) UNIVERSAL=1 ;;
     --dmg) DMG=1 ;;
+    --notarize) NOTARIZE=1 ;;
     *) echo "unknown option: $arg" >&2; exit 2 ;;
   esac
 done
 
+if [ "$NOTARIZE" = 1 ]; then
+  # Checked before the build, so a missing secret costs seconds, not a build.
+  ./scripts/sign-macos.sh --check
+fi
+
 VERSION=$(sed -n 's/^version = "\(.*\)"$/\1/p' Cargo.toml | head -1)
 [ -n "$VERSION" ] || { echo "could not read the version from Cargo.toml" >&2; exit 1; }
 
@@ -98,13 +116,13 @@ codesign --verify --strict "$APP"
 
 echo "Built $(pwd)/$APP ($(du -sh "$APP" | cut -f1), version $VERSION, macOS $MACOSX_DEPLOYMENT_TARGET or later)"
 
-if [ "$DMG" = 1 ]; then
-  STAGE="$WORK/dmg"
-  mkdir -p "$STAGE"
-  cp -R "$APP" "$STAGE/"
-  ln -s /Applications "$STAGE/Applications"
+if [ "$NOTARIZE" = 1 ]; then
+  ./scripts/sign-macos.sh "$APP" dist
+elif [ "$DMG" = 1 ]; then
   DMG_PATH="dist/Codeman-$VERSION.dmg"
-  rm -f "$DMG_PATH"
-  hdiutil create -quiet -volname "Codeman" -srcfolder "$STAGE" -ov -format UDZO "$DMG_PATH"
+  ./scripts/make-dmg.sh "$APP" "$DMG_PATH"
+  if [ -n "${SIGN_IDENTITY:-}" ]; then
+    codesign --force --timestamp --sign "$SIGN_IDENTITY" "$DMG_PATH"
+  fi
   echo "Built $(pwd)/$DMG_PATH ($(du -sh "$DMG_PATH" | cut -f1))"
 fi
diff --git a/packages/desktop/scripts/make-dmg.sh b/packages/desktop/scripts/make-dmg.sh
new file mode 100755
index 00000000..22eea160
--- /dev/null
+++ b/packages/desktop/scripts/make-dmg.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Put Codeman.app in a compressed disk image next to a link to /Applications,
+# so opening the image shows the app and the folder to drag it into.
+#
+#   packages/desktop/scripts/make-dmg.sh <Codeman.app> <out.dmg>
+#
+# bundle-macos.sh (--dmg) and sign-macos.sh both call it, so a local test DMG
+# and the release DMG are laid out the same way. It signs nothing.
+set -euo pipefail
+
+[ "$(uname -s)" = Darwin ] || { echo "make-dmg.sh runs on macOS only" >&2; exit 1; }
+[ $# -eq 2 ] || { echo "usage: $0 <Codeman.app> <out.dmg>" >&2; exit 2; }
+
+APP=$1
+DMG=$2
+[ -d "$APP/Contents/MacOS" ] || { echo "$APP is not an app bundle" >&2; exit 2; }
+
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+
+STAGE="$WORK/dmg"
+mkdir -p "$STAGE"
+# ditto keeps what cp -R can lose: extended attributes, and with them a
+# stapled notarization ticket.
+ditto "$APP" "$STAGE/$(basename "$APP")"
+ln -s /Applications "$STAGE/Applications"
+
+# Hosted macOS runners now and then fail hdiutil with "Resource busy"; the
+# same command a few seconds later passes.
+rm -f "$DMG"
+tries=1
+until hdiutil create -quiet -volname Codeman -srcfolder "$STAGE" -ov -format UDZO "$DMG"; do
+  if [ "$tries" -ge 3 ]; then
+    echo "hdiutil create failed $tries times" >&2
+    exit 1
+  fi
+  tries=$((tries + 1))
+  echo "hdiutil create failed, trying again in 10 seconds" >&2
+  rm -f "$DMG"
+  sleep 10
+done
+hdiutil verify -quiet "$DMG"
diff --git a/packages/desktop/scripts/sign-macos.sh b/packages/desktop/scripts/sign-macos.sh
new file mode 100755
index 00000000..46266321
--- /dev/null
+++ b/packages/desktop/scripts/sign-macos.sh
@@ -0,0 +1,144 @@
+#!/usr/bin/env bash
+# Sign Codeman.app with a Developer ID, have Apple notarize it and staple the
+# ticket to it, then build Codeman.dmg around the stapled app and do the same
+# for the DMG. On macOS.
+#
+#   packages/desktop/scripts/sign-macos.sh <Codeman.app> <out-dir>
+#   packages/desktop/scripts/sign-macos.sh --check   # only check the environment below
+#
+# <Codeman.app> is re-signed and stapled in place. <out-dir> receives
+# Codeman.dmg and Codeman.dmg.sha256, the latter with the bare file name in it,
+# so `shasum -a 256 -c Codeman.dmg.sha256` works next to a downloaded copy. Both
+# appear only once every check passed; a failed run leaves neither, not even an
+# older pair, so nothing half-done can be uploaded by mistake.
+#
+# The environment names who signs:
+#   SIGN_IDENTITY       a "Developer ID Application: ..." identity in a keychain
+#                       on the search list, by name or by the SHA-1 hash that
+#                       `security find-identity -v -p codesigning` prints
+# and how to reach Apple's notary service, either through a profile saved with
+# `xcrun notarytool store-credentials <profile> --apple-id ... --team-id ...`:
+#   NOTARY_PROFILE      the profile's name
+#   NOTARY_KEYCHAIN     optional, the keychain that holds it (default: login)
+# or with the Apple ID itself:
+#   APPLE_ID, APPLE_APP_PASSWORD (an app-specific password), APPLE_TEAM_ID
+#
+# By hand, on a Mac with the certificate in the login keychain:
+#   SIGN_IDENTITY="Developer ID Application: ..." NOTARY_PROFILE=codeman-notary \
+#     packages/desktop/scripts/sign-macos.sh packages/desktop/dist/Codeman.app packages/desktop/dist
+#
+# The release workflow (.github/workflows/desktop-dmg.yml) runs it in a job that
+# builds nothing: the job that runs cargo, and with it the build script of every
+# crate in Cargo.lock, never holds a signing secret.
+set -euo pipefail
+
+[ "$(uname -s)" = Darwin ] || { echo "sign-macos.sh runs on macOS only" >&2; exit 1; }
+
+DESKTOP=$(cd "$(dirname "$0")/.." && pwd)
+ENTITLEMENTS="$DESKTOP/macos/entitlements.plist"
+
+# Fails with the name of what is missing, before any work, so a missing secret
+# costs seconds rather than a build.
+check_env() {
+  if [ -z "${SIGN_IDENTITY:-}" ]; then
+    echo "sign-macos.sh needs SIGN_IDENTITY" >&2
+    exit 2
+  fi
+  if [ -n "${NOTARY_PROFILE:-}" ]; then
+    return 0
+  fi
+  local name
+  for name in APPLE_ID APPLE_APP_PASSWORD APPLE_TEAM_ID; do
+    if [ -z "$(eval "printf '%s' \"\${$name:-}\"")" ]; then
+      echo "sign-macos.sh needs NOTARY_PROFILE, or APPLE_ID, APPLE_APP_PASSWORD and APPLE_TEAM_ID ($name is empty)" >&2
+      exit 2
+    fi
+  done
+}
+
+if [ "${1:-}" = --check ] && [ $# -eq 1 ]; then
+  check_env
+  exit 0
+fi
+[ $# -eq 2 ] || { echo "usage: $0 <Codeman.app> <out-dir> | --check" >&2; exit 2; }
+check_env
+
+APP=$1
+OUT=$2
+[ -d "$APP/Contents/MacOS" ] || { echo "$APP is not an app bundle" >&2; exit 2; }
+mkdir -p "$OUT"
+OUT=$(cd "$OUT" && pwd)
+rm -f "$OUT/Codeman.dmg" "$OUT/Codeman.dmg.sha256"
+NAME=$(basename "$APP" .app)
+
+if [ -n "${NOTARY_PROFILE:-}" ]; then
+  NOTARY_AUTH=(--keychain-profile "$NOTARY_PROFILE")
+  if [ -n "${NOTARY_KEYCHAIN:-}" ]; then
+    NOTARY_AUTH=("${NOTARY_AUTH[@]}" --keychain "$NOTARY_KEYCHAIN")
+  fi
+else
+  # On notarytool's command line, which the job's log never shows.
+  NOTARY_AUTH=(--apple-id "$APPLE_ID" --password "$APPLE_APP_PASSWORD" --team-id "$APPLE_TEAM_ID")
+fi
+
+WORK=$(mktemp -d)
+trap 'rm -rf "$WORK"' EXIT
+
+# Submit a file to the notary service and wait. Anything but Accepted stops the
+# script with the submission id and Apple's log, which names the file and the
+# reason (an unsigned binary, a missing timestamp, no hardened runtime...).
+notarize() {
+  local file=$1 result="$WORK/notary.plist" rc=0 status id
+  echo "Submitting $(basename "$file") to Apple's notary service"
+  xcrun notarytool submit "$file" "${NOTARY_AUTH[@]}" --wait --timeout 45m \
+    --output-format plist > "$result" || rc=$?
+  status=$(/usr/libexec/PlistBuddy -c 'Print :status' "$result" 2>/dev/null || true)
+  id=$(/usr/libexec/PlistBuddy -c 'Print :id' "$result" 2>/dev/null || true)
+  if [ "$status" != Accepted ]; then
+    echo "Notarization of $(basename "$file") ended as '${status:-unknown}' (submission ${id:-none}, notarytool exit $rc)" >&2
+    cat "$result" >&2 || true
+    if [ -n "$id" ]; then
+      xcrun notarytool log "$id" "${NOTARY_AUTH[@]}" >&2 || true
+    fi
+    exit 1
+  fi
+  echo "Notarized $(basename "$file") (submission $id)"
+}
+
+# The app: hardened runtime (which notarization requires), a secure timestamp,
+# and the entitlements the hardened runtime needs for microphone and camera.
+codesign --force --options runtime --timestamp --entitlements "$ENTITLEMENTS" \
+  --sign "$SIGN_IDENTITY" "$APP"
+codesign --verify --strict --verbose=2 "$APP"
+DETAILS=$(codesign --display --verbose=2 "$APP" 2>&1)
+printf '%s\n' "$DETAILS" | grep -E '^(Authority|TeamIdentifier|Timestamp)=' || true
+case "$DETAILS" in
+  *"Authority=Developer ID Application: "*) ;;
+  *) echo "$APP is not signed with a Developer ID Application certificate" >&2; exit 1 ;;
+esac
+case "$DETAILS" in
+  *"(runtime)"*) ;;
+  *) echo "$APP is signed without the hardened runtime" >&2; exit 1 ;;
+esac
+
+ditto -c -k --keepParent "$APP" "$WORK/$NAME.zip"
+notarize "$WORK/$NAME.zip"
+xcrun stapler staple "$APP"
+xcrun stapler validate "$APP"
+spctl --assess --type execute --verbose=2 "$APP"
+
+# The DMG around the stapled app, signed and notarized in its own right, so the
+# image opens without a warning and the app inside opens offline.
+DMG="$WORK/Codeman.dmg"
+"$DESKTOP/scripts/make-dmg.sh" "$APP" "$DMG"
+codesign --force --timestamp --sign "$SIGN_IDENTITY" "$DMG"
+codesign --verify --strict --verbose=2 "$DMG"
+notarize "$DMG"
+xcrun stapler staple "$DMG"
+xcrun stapler validate "$DMG"
+spctl --assess --type open --context context:primary-signature --verbose=2 "$DMG"
+
+(cd "$WORK" && shasum -a 256 Codeman.dmg > Codeman.dmg.sha256)
+mv "$DMG" "$WORK/Codeman.dmg.sha256" "$OUT/"
+echo "Signed and notarized $APP"
+echo "Built $OUT/Codeman.dmg ($(du -h "$OUT/Codeman.dmg" | cut -f1)), sha256 $(cut -d' ' -f1 "$OUT/Codeman.dmg.sha256")"