diff --git a/lib/bash/cli/lib_cli.sh b/lib/bash/cli/lib_cli.sh
index 40ef9d0..00e4f36 100644
--- a/lib/bash/cli/lib_cli.sh
+++ b/lib/bash/cli/lib_cli.sh
@@ -61,7 +61,19 @@ __base_bash_libs_cli_valid_model__() {
 }
 
 __base_bash_libs_cli_valid_segment__() {
-    [[ "${1-}" =~ ^[A-Za-z0-9_-]+$ ]]
+    [[ "${1-}" == - || "${1-}" =~ ^[A-Za-z0-9_][A-Za-z0-9_-]*$ ]]
+}
+
+__base_bash_libs_cli_builtin_option_action__() {
+    case "${1-}" in
+    -h | --help) printf 'help' ;;
+    -V | --version) printf 'version' ;;
+    *) return 1 ;;
+    esac
+}
+
+__base_bash_libs_cli_is_builtin_option_token__() {
+    __base_bash_libs_cli_builtin_option_action__ "${1-}" > /dev/null
 }
 
 __base_bash_libs_cli_valid_path__() {
@@ -786,7 +798,8 @@ base_cli_validate_model() {
         path="${route%%|token|*}"
         token="${route#*|token|}"
         name="${__base_bash_libs_cli_models[$key]}"
-        if ! __base_bash_libs_cli_option_lookup__ "$model" "$path" "$token" found_name found_path found_type ||
+        if __base_bash_libs_cli_is_builtin_option_token__ "$token" ||
+            ! __base_bash_libs_cli_option_lookup__ "$model" "$path" "$token" found_name found_path found_type ||
             [[ "$found_name" != "$name" || "$found_path" != "$path" ]]; then
             unreachable_routes+=("option:$path:$token")
         fi
@@ -961,6 +974,10 @@ base_cli_option() {
             __base_bash_libs_cli_declaration_usage__ "base_cli_option: invalid option token '$token'."
             return 2
         fi
+        if __base_bash_libs_cli_is_builtin_option_token__ "$token"; then
+            __base_bash_libs_cli_declaration_usage__ "base_cli_option: token '$token' is reserved for built-in CLI behavior."
+            return 2
+        fi
         if [[ "$token" == *=* ]]; then
             __base_bash_libs_cli_declaration_usage__ "base_cli_option: option token '$token' cannot contain '='."
             return 2
@@ -1334,6 +1351,7 @@ __base_bash_libs_cli_apply_positionals__() {
 # Usage: base_cli_parse model -- [argv...]
 base_cli_parse() {
     local model="${1-}" current path="" token option_value name type child_path option_path
+    local builtin_action
     # shellcheck disable=SC2034 # Pass-by-name outputs used only to probe whether an option token is registered.
     local probe_name probe_path probe_type
     local parse_options=1 parse_commands=1
@@ -1357,13 +1375,17 @@ base_cli_parse() {
             parse_commands=0
             continue
         fi
-        if ((parse_options)) && [[ "$current" == -h || "$current" == --help ]]; then
+        builtin_action=""
+        if ((parse_options)); then
+            builtin_action="$(__base_bash_libs_cli_builtin_option_action__ "$current" || true)"
+        fi
+        if [[ "$builtin_action" == help ]]; then
             BASE_BASH_LIBS_CLI_RESULT_COMMAND="$path"
             BASE_BASH_LIBS_CLI_RESULT_ACTION="help"
             base_cli_help "$model" "$path"
             return $?
         fi
-        if ((parse_options)) && [[ "$current" == -V || "$current" == --version ]]; then
+        if [[ "$builtin_action" == version ]]; then
             if [[ -n "$path" || -z "${__base_bash_libs_cli_models["$model|meta|version"]-}" ]]; then
                 __base_bash_libs_cli_usage_error__ "$model" "$path" "version is not available for this command."
                 return 2
diff --git a/lib/bash/cli/tests/lib_cli.bats b/lib/bash/cli/tests/lib_cli.bats
index ed4c939..3dcf580 100644
--- a/lib/bash/cli/tests/lib_cli.bats
+++ b/lib/bash/cli/tests/lib_cli.bats
@@ -489,6 +489,21 @@ EOF
     [[ "$output" == *"route 'u' was provided more than once"* ]]
 }
 
+@test "a lone dash is accepted as a model name command name and alias" {
+    base_cli_model_init dash_model name=-
+    base_cli_validate_model dash_model
+
+    base_cli_model_init dash_command name=dash-command
+    base_cli_command dash_command - "Read standard input"
+    base_cli_parse dash_command -- -
+    [ "$BASE_BASH_LIBS_CLI_RESULT_COMMAND" = - ]
+
+    base_cli_model_init dash_alias name=dash-alias
+    base_cli_command dash_alias stdin "Read standard input" aliases=-
+    base_cli_parse dash_alias -- -
+    [ "$BASE_BASH_LIBS_CLI_RESULT_COMMAND" = stdin ]
+}
+
 @test "ancestor and child option names and tokens cannot shadow each other" {
     base_cli_model_init ancestor_first name=ancestor-first
     base_cli_command ancestor_first child "Child"
@@ -530,6 +545,36 @@ EOF
     [ "$status" -eq 2 ]
 }
 
+@test "built-in option tokens and option-shaped command routes are unreachable" {
+    local before token path
+
+    base_cli_model_init reserved name=reserved version=2.0.0
+    base_cli_command reserved run "Run"
+    before="$(model_registry_dump reserved)"
+    for path in '' run; do
+        for token in -h --help -V --version; do
+            bats_run base_cli_option reserved "$path" custom value "$token"
+            [ "$status" -eq 2 ]
+            [[ "$output" == *"reserved for built-in CLI behavior"* ]]
+            [ "$(model_registry_dump reserved)" = "$before" ]
+        done
+    done
+
+    bats_run base_cli_command reserved --diagnose "Unreachable route"
+    [ "$status" -eq 2 ]
+    bats_run base_cli_command reserved run/-diagnose "Unreachable nested route"
+    [ "$status" -eq 2 ]
+    bats_run base_cli_command reserved manage "Manage" aliases=-m
+    [ "$status" -eq 2 ]
+
+    bats_run base_cli_declare reserved_table \
+        'model|name=reserved-table|version=2.0.0' \
+        'command|path=run|description=Run' \
+        'option|path=run|name=help|type=flag|tokens=--help'
+    [ "$status" -eq 2 ]
+    [ "$(model_registry_dump reserved_table)" = "" ]
+}
+
 @test "model validation detects unreachable command and option routes" {
     base_cli_model_init routes name=routes
     base_cli_command routes user "User" aliases=u
@@ -541,11 +586,18 @@ EOF
     __base_bash_libs_cli_models['routes|option|child|meta|child_mode|tokens']='--mode'
     __base_bash_libs_cli_models['routes|option|child|token|--mode']=child_mode
 
+    __base_bash_libs_cli_models['routes|option|child|meta|built_in|type']=flag
+    __base_bash_libs_cli_models['routes|option|child|meta|built_in|tokens']='--help'
+    __base_bash_libs_cli_models['routes|option|child|token|--help']=built_in
+    __base_bash_libs_cli_option_name_index['routes|built_in']=child
+    __base_bash_libs_cli_option_token_index['routes|--help']=child
+
     bats_run base_cli_validate_model routes
 
     [ "$status" -eq 2 ]
     [[ "$output" == *"alias:user:u"* ]]
     [[ "$output" == *"option:child:--mode"* ]]
+    [[ "$output" == *"option:child:--help"* ]]
 }
 
 @test "option validators may render help without corrupting required-option traversal" {