diff --git a/packages/mosaic/framework/tools/git/issue-assign.sh b/packages/mosaic/framework/tools/git/issue-assign.sh
index c1c26c0c..b7192005 100755
--- a/packages/mosaic/framework/tools/git/issue-assign.sh
+++ b/packages/mosaic/framework/tools/git/issue-assign.sh
@@ -40,29 +40,29 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 # Parse arguments
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE="$2"
             shift 2
             ;;
         -a|--assignee)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ASSIGNEE="$2"
             shift 2
             ;;
         -l|--labels)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-close.sh b/packages/mosaic/framework/tools/git/issue-close.sh
index 7109247c..78d92384 100755
--- a/packages/mosaic/framework/tools/git/issue-close.sh
+++ b/packages/mosaic/framework/tools/git/issue-close.sh
@@ -25,14 +25,14 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
         -b|--body|-c|--comment)
             # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
             # a backward-compatible alias.
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-comment.sh b/packages/mosaic/framework/tools/git/issue-comment.sh
index 93231c99..d5b74028 100755
--- a/packages/mosaic/framework/tools/git/issue-comment.sh
+++ b/packages/mosaic/framework/tools/git/issue-comment.sh
@@ -46,7 +46,7 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
@@ -54,12 +54,12 @@ while [[ $# -gt 0 ]]; do
             # R1 (2026-08-28): --body is the canonical flag, matching
             # issue-create/issue-edit/pr-create/pr-edit; -c/--comment stays a
             # backward-compatible alias.
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -l|--login)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LOGIN_OVERRIDE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-create.sh b/packages/mosaic/framework/tools/git/issue-create.sh
index 3e42e14a..e0b061a6 100755
--- a/packages/mosaic/framework/tools/git/issue-create.sh
+++ b/packages/mosaic/framework/tools/git/issue-create.sh
@@ -85,28 +85,28 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -l|--labels)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-edit.sh b/packages/mosaic/framework/tools/git/issue-edit.sh
index f40a2f34..20465de9 100755
--- a/packages/mosaic/framework/tools/git/issue-edit.sh
+++ b/packages/mosaic/framework/tools/git/issue-edit.sh
@@ -26,27 +26,27 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
         -t|--title)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -l|--labels)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-list.sh b/packages/mosaic/framework/tools/git/issue-list.sh
index 534c52bb..54ca1ce8 100755
--- a/packages/mosaic/framework/tools/git/issue-list.sh
+++ b/packages/mosaic/framework/tools/git/issue-list.sh
@@ -44,38 +44,38 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 while [[ $# -gt 0 ]]; do
     case $1 in
         -s|--state)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             STATE="$2"
             shift 2
             ;;
         -l|--label)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABEL="$2"
             shift 2
             ;;
         -m|--milestone)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
         -a|--assignee)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ASSIGNEE="$2"
             shift 2
             ;;
         -n|--limit)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LIMIT="$2"
             shift 2
             ;;
         -r|--repo)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             REPO_OVERRIDE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-reopen.sh b/packages/mosaic/framework/tools/git/issue-reopen.sh
index 58e80382..d1011035 100755
--- a/packages/mosaic/framework/tools/git/issue-reopen.sh
+++ b/packages/mosaic/framework/tools/git/issue-reopen.sh
@@ -24,14 +24,14 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
         -b|--body|-c|--comment)
             # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
             # a backward-compatible alias.
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/issue-view.sh b/packages/mosaic/framework/tools/git/issue-view.sh
index 4d45ce87..dd0364f5 100755
--- a/packages/mosaic/framework/tools/git/issue-view.sh
+++ b/packages/mosaic/framework/tools/git/issue-view.sh
@@ -82,7 +82,7 @@ if comments:
 while [[ $# -gt 0 ]]; do
     case $1 in
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE_NUMBER="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/lane-brief.sh b/packages/mosaic/framework/tools/git/lane-brief.sh
index 5d1df846..c8a07180 100755
--- a/packages/mosaic/framework/tools/git/lane-brief.sh
+++ b/packages/mosaic/framework/tools/git/lane-brief.sh
@@ -37,11 +37,11 @@ usage_error() {
 }
 while [[ $# -gt 0 ]]; do
   case "$1" in
-    -r|--repo) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; REPO="$2"; shift 2 ;;
-    -m|--milestone) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; MILESTONE="$2"; shift 2 ;;
-    -l|--label|--labels) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; LABEL="$2"; shift 2 ;;
-    -L|--login) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; LOGIN="$2"; shift 2 ;;
-    -n|--limit) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; LIMIT="$2"; shift 2 ;;
+    -r|--repo) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; REPO="$2"; shift 2 ;;
+    -m|--milestone) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; MILESTONE="$2"; shift 2 ;;
+    -l|--label|--labels) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LABEL="$2"; shift 2 ;;
+    -L|--login) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LOGIN="$2"; shift 2 ;;
+    -n|--limit) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LIMIT="$2"; shift 2 ;;
     -h|--help) grep '^#' "$0" | sed 's/^# \?//'; exit 0 ;;
     *) usage_error "unknown option: $1" ;;
   esac
diff --git a/packages/mosaic/framework/tools/git/milestone-close.sh b/packages/mosaic/framework/tools/git/milestone-close.sh
index 92162bb8..9f31b542 100755
--- a/packages/mosaic/framework/tools/git/milestone-close.sh
+++ b/packages/mosaic/framework/tools/git/milestone-close.sh
@@ -21,7 +21,7 @@ TITLE=""
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/milestone-create.sh b/packages/mosaic/framework/tools/git/milestone-create.sh
index 35361c0f..67202fb2 100755
--- a/packages/mosaic/framework/tools/git/milestone-create.sh
+++ b/packages/mosaic/framework/tools/git/milestone-create.sh
@@ -45,23 +45,23 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -d|--desc)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DESCRIPTION="$2"
             shift 2
             ;;
         --due)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             DUE_DATE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/milestone-list.sh b/packages/mosaic/framework/tools/git/milestone-list.sh
index 64beff8e..2704cc9d 100755
--- a/packages/mosaic/framework/tools/git/milestone-list.sh
+++ b/packages/mosaic/framework/tools/git/milestone-list.sh
@@ -21,7 +21,7 @@ STATE="open"
 while [[ $# -gt 0 ]]; do
     case $1 in
         -s|--state)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             STATE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/pr-close.sh b/packages/mosaic/framework/tools/git/pr-close.sh
index f05a803f..9a9dbdf7 100755
--- a/packages/mosaic/framework/tools/git/pr-close.sh
+++ b/packages/mosaic/framework/tools/git/pr-close.sh
@@ -24,14 +24,14 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -n|--number)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             PR_NUMBER="$2"
             shift 2
             ;;
         -b|--body|-c|--comment)
             # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
             # a backward-compatible alias.
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/pr-create.sh b/packages/mosaic/framework/tools/git/pr-create.sh
index 6f599c0f..2226b091 100755
--- a/packages/mosaic/framework/tools/git/pr-create.sh
+++ b/packages/mosaic/framework/tools/git/pr-create.sh
@@ -142,44 +142,44 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 # Parse arguments
 while [[ $# -gt 0 ]]; do
     case $1 in
         -t|--title)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             TITLE="$2"
             shift 2
             ;;
         -b|--body)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BODY="$2"
             shift 2
             ;;
         -B|--base)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             BASE_BRANCH="$2"
             shift 2
             ;;
         -H|--head)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             HEAD_BRANCH="$2"
             shift 2
             ;;
         -l|--labels)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LABELS="$2"
             shift 2
             ;;
         -m|--milestone)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             MILESTONE="$2"
             shift 2
             ;;
         -i|--issue)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ISSUE="$2"
             shift 2
             ;;
diff --git a/packages/mosaic/framework/tools/git/pr-edit.sh b/packages/mosaic/framework/tools/git/pr-edit.sh
index ac167865..db520f7d 100755
--- a/packages/mosaic/framework/tools/git/pr-edit.sh
+++ b/packages/mosaic/framework/tools/git/pr-edit.sh
@@ -57,24 +57,24 @@ EOF
 # distinct from provider, credential, and verification failures (exit 1).
 usage_error() {
     echo "Error: $*" >&2
-    usage
+    usage >&2
 }
 
 while [[ $# -gt 0 ]]; do
     case "$1" in
-        -n|--number) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; PR_NUMBER="${2:-}"; shift 2 ;;
-        -t|--title) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; TITLE="${2:-}"; shift 2 ;;
-        -b|--body) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; BODY="${2:-}"; shift 2 ;;
-        -B|--base) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; BASE_BRANCH="${2:-}"; shift 2 ;;
+        -n|--number) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; PR_NUMBER="${2:-}"; shift 2 ;;
+        -t|--title) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; TITLE="${2:-}"; shift 2 ;;
+        -b|--body) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; BODY="${2:-}"; shift 2 ;;
+        -B|--base) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; BASE_BRANCH="${2:-}"; shift 2 ;;
         --draft)
             [[ "$DRAFT_MODE" != "ready" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 2; }
             DRAFT_MODE="draft"; shift ;;
         --ready)
             [[ "$DRAFT_MODE" != "draft" ]] || { echo "Error: --draft and --ready are mutually exclusive" >&2; exit 2; }
             DRAFT_MODE="ready"; shift ;;
-        -l|--login) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; LOGIN_OVERRIDE="${2:-}"; shift 2 ;;
-        -r|--repo) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; REPO_OVERRIDE="${2:-}"; shift 2 ;;
-        -H|--host) [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"; HOST_OVERRIDE="${2:-}"; shift 2 ;;
+        -l|--login) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; LOGIN_OVERRIDE="${2:-}"; shift 2 ;;
+        -r|--repo) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; REPO_OVERRIDE="${2:-}"; shift 2 ;;
+        -H|--host) [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"; HOST_OVERRIDE="${2:-}"; shift 2 ;;
         -h|--help) usage 0 ;;
         *) echo "Unknown option: $1" >&2; usage ;;
     esac
diff --git a/packages/mosaic/framework/tools/git/pr-review.sh b/packages/mosaic/framework/tools/git/pr-review.sh
index 716e3fe7..e468222d 100755
--- a/packages/mosaic/framework/tools/git/pr-review.sh
+++ b/packages/mosaic/framework/tools/git/pr-review.sh
@@ -55,34 +55,34 @@ usage_error() {
 while [[ $# -gt 0 ]]; do
     case $1 in
         -n|--number)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             PR_NUMBER="$2"
             shift 2
             ;;
         -a|--action)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             ACTION="$2"
             shift 2
             ;;
         -b|--body|-c|--comment)
             # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
             # a backward-compatible alias.
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             COMMENT="$2"
             shift 2
             ;;
         -l|--login)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             LOGIN_OVERRIDE="$2"
             shift 2
             ;;
         -r|--repo)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             REPO_OVERRIDE="$2"
             shift 2
             ;;
         -H|--host)
-            [[ $# -ge 2 && "$2" != --* && ! "$2" =~ ^-[a-zA-Z]$ ]] || usage_error "option $1 requires a value (option-like values are rejected)"
+            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
             HOST_OVERRIDE="$2"
             shift 2
             ;;