diff --git a/dist/cz/bin/cz b/dist/cz/bin/cz
index 554157e..a92dd28 100755
--- a/dist/cz/bin/cz
+++ b/dist/cz/bin/cz
@@ -101,7 +101,7 @@ parse() {
 			-[c]?*) OPTARG=$1; shift
 				eval 'set -- "${OPTARG%"${OPTARG#??}"}" "${OPTARG#??}"' ${1+'"$@"'}
 				;;
-			-[rdemqhV]?*) OPTARG=$1; shift
+			-[rdembqhV]?*) OPTARG=$1; shift
 				eval 'set -- "${OPTARG%"${OPTARG#??}"}" -"${OPTARG#??}"' ${1+'"$@"'}
 				case $2 in --*) set -- "$1" unknown "$2" && REST=x; esac;OPTARG= ;;
 		esac
@@ -132,7 +132,7 @@ parse() {
 				eval '[ ${OPTARG+x} ] &&:' && OPTARG='1' || OPTARG=''
 				MULTI_SCOPE="$OPTARG"
 				;;
-			'--breaking-footer'|'--no-breaking-footer')
+			'-b'|'--breaking-footer'|'--no-breaking-footer')
 				[ "${OPTARG:-}" ] && OPTARG=${OPTARG#*\=} && set "noarg" "$1" && break
 				eval '[ ${OPTARG+x} ] &&:' && OPTARG='1' || OPTARG=''
 				BREAKING_FOOTER="$OPTARG"
@@ -191,7 +191,7 @@ Options:
   -d, --{no-}defined-scope    Scope must exist in [scopes]
   -e, --{no-}enforce-patterns Scope must match file patterns (implies -d)
   -m, --{no-}multi-scope      Allow multiple scopes like feat(api,db):
-      --{no-}breaking-footer  Require BREAKING CHANGE footer when ! is used
+  -b, --{no-}breaking-footer  Require BREAKING CHANGE footer when ! is used
   -q, --quiet                 Suppress warnings and non-essential output
   -h, --help                  
   -V, --version               
@@ -214,6 +214,60 @@ GETOPTIONSHERE
 # --- begin: scripts/cz/config.sh ---
 
 
+# --- begin: scripts/cz/helpers.sh ---
+
+
+# --- begin: scripts/cz/error_codes.sh ---
+
+
+# @start-kcov-exclude - static data table
+declare -gA ERR_CODES=(
+	["empty-message"]="empty commit message"
+	["header-format"]="commits MUST be prefixed with a type, followed by a colon and space"
+	["type-enum"]="unknown type '%s'"
+	["description-empty"]="description MUST immediately follow the colon and space"
+	["body-leading-blank"]="body MUST begin one blank line after the description"
+	["breaking-footer"]="if included in the type/scope prefix, breaking changes MUST be indicated by a BREAKING CHANGE footer"
+	["scope-required"]="scope required"
+	["scope-enum"]="unknown scope '%s'"
+	["scope-missing-config"]="scope '%s' used but no scopes defined in config"
+	["scope-file-required"]="scope required for scoped files"
+	["multi-scope-disabled"]="multi-scope not enabled"
+	["files-scope-mismatch"]="files do not match scope '%s'"
+	["files-scopes-mismatch"]="files do not match scopes '%s'"
+	["config-not-found"]="config file not found: %s"
+	["gum-not-found"]="gum is required for interactive mode"
+	["description-required"]="description MUST NOT be empty"
+	["breaking-explanation"]="breaking change explanation is required"
+	["file-exists"]="'%s' already exists (use -f to overwrite)"
+	["not-git-repo"]="not a git repository"
+	["hook-action-unknown"]="unknown hook action '%s'"
+	["hook-exists"]="existing commit-msg hook found"
+	["hook-foreign"]="commit-msg hook was not installed by cz"
+)
+# @end-kcov-exclude
+# --- end: scripts/cz/error_codes.sh ---
+
+_err() {
+	[[ -n "${QUIET:-}" ]] && return
+	local code="$1"
+	shift
+	local msg="${ERR_CODES[$code]}"
+	if [[ -n "$msg" ]]; then
+		printf -v msg "$msg" "$@"
+		echo "cz: error: $msg [$code]" >&2
+	else
+		echo "cz: error: $code $* [unknown]" >&2
+	fi
+}
+_hint() { [[ -n "${QUIET:-}" ]] || echo "$1" >&2; }
+
+_trim() {
+	local v="${!1}"
+	v="${v#"${v%%[![:space:]]*}"}"
+	printf -v "$1" '%s' "${v%"${v##*[![:space:]]}"}"
+}
+# --- end: scripts/cz/helpers.sh ---
 # --- begin: scripts/cz/config_defaults.sh ---
 
 format_config() {
@@ -330,14 +384,14 @@ find_config() {
 load_config() {
 	if [[ -n "$CONFIG_FILE" ]]; then
 		if [[ ! -f "$CONFIG_FILE" ]]; then
-			echo "cz: error: config file not found: $CONFIG_FILE" >&2
+			_err config-not-found "$CONFIG_FILE"
 			exit 1
 		fi
 
 		parse_config <"$CONFIG_FILE"
 
 		if [[ ${#CFG_TYPES[@]} -eq 0 ]]; then
-			[[ -z "${QUIET:-}" ]] && echo "cz: warning: no [types] in $CONFIG_FILE, using defaults" >&2
+			_hint "cz: warning: no [types] in $CONFIG_FILE, using defaults"
 			_set_default_types
 		fi
 	else
@@ -393,6 +447,7 @@ cmd_parse() {
 # --- begin: scripts/cz/cmd_init.sh ---
 
 
+# --- skipped (already included): scripts/cz/helpers.sh ---
 # --- skipped (already included): scripts/cz/config_defaults.sh ---
 
 cmd_init() {
@@ -404,7 +459,7 @@ cmd_init() {
 	fi
 
 	if [[ -f "$OUTPUT_FILE" && -z "${FORCE:-}" ]]; then
-		echo "cz: error: '$OUTPUT_FILE' already exists (use -f to overwrite)" >&2
+		_err file-exists "$OUTPUT_FILE"
 		return 1
 	fi
 
@@ -414,12 +469,14 @@ cmd_init() {
 # --- begin: scripts/cz/cmd_hook.sh ---
 
 
+# --- skipped (already included): scripts/cz/helpers.sh ---
+
 cmd_hook() {
 	local action="${1:-status}"
 
 	local git_dir
 	git_dir="$(git rev-parse --git-dir 2>/dev/null)" || {
-		echo "cz: error: not a git repository" >&2
+		_err not-git-repo
 		return 1
 	}
 
@@ -437,8 +494,8 @@ cmd_hook() {
 			hook_status "$hook_path" "$hook_marker"
 			;;
 		*)
-			echo "cz: error: unknown hook action '$action'" >&2
-			echo "Usage: cz hook [install|uninstall|status]" >&2
+			_err hook-action-unknown "$action"
+			_hint "Usage: cz hook [install|uninstall|status]"
 			return 2
 			;;
 	esac
@@ -453,8 +510,8 @@ hook_install() {
 			echo "cz: hook already installed"
 			return 0
 		else
-			echo "cz: error: existing commit-msg hook found" >&2
-			echo "Remove it manually or add 'cz lint < \"\$1\"' to it" >&2
+			_err hook-exists
+			_hint "Remove it manually or add 'cz lint < \"\$1\"' to it"
 			return 1
 		fi
 	fi
@@ -485,7 +542,7 @@ hook_uninstall() {
 	fi
 
 	if ! grep -q "$hook_marker" "$hook_path" 2>/dev/null; then
-		echo "cz: error: commit-msg hook was not installed by cz" >&2
+		_err hook-foreign
 		return 1
 	fi
 
@@ -518,15 +575,7 @@ hook_status() {
 # --- begin: scripts/cz/path_validator.sh ---
 
 
-# --- begin: scripts/cz/helpers.sh ---
-
-
-_trim() {
-	local v="${!1}"
-	v="${v#"${v%%[![:space:]]*}"}"
-	printf -v "$1" '%s' "${v%"${v##*[![:space:]]}"}"
-}
-# --- end: scripts/cz/helpers.sh ---
+# --- skipped (already included): scripts/cz/helpers.sh ---
 # --- skipped (already included): scripts/cz/config_parser.sh ---
 
 file_matches_pattern() {
@@ -633,10 +682,8 @@ validate_strict_no_scope() {
 }
 # --- end: scripts/cz/path_validator.sh ---
 
-_err() { [[ -n "${QUIET:-}" ]] || echo "cz: error: $1" >&2; }
-_hint() { [[ -n "${QUIET:-}" ]] || echo "$1" >&2; }
 _scope_err() {
-	_err "unknown scope '$1'"
+	_err scope-enum "$1"
 	_hint "Defined scopes: ${!CFG_SCOPES[*]}"
 }
 _show_errors() {
@@ -663,7 +710,7 @@ cmd_lint() {
 	message="$(cat)"
 
 	[[ -z "$message" ]] && {
-		_err "empty commit message"
+		_err empty-message
 		return 1
 	}
 
@@ -673,8 +720,8 @@ cmd_lint() {
 	local pattern='^([a-z]+)(\(([a-zA-Z0-9_@/,*-]+)\))?(!)?: (.+)$'
 
 	if [[ ! "$first_line" =~ $pattern ]]; then
-		_err "invalid commit format"
-		_hint "Expected: <type>[(scope)]: <description>"
+		_err header-format
+		_hint "Expected: <type>[(<scope>)][!]: <description>"
 		return 1
 	fi
 
@@ -682,13 +729,19 @@ cmd_lint() {
 	local breaking="${BASH_REMATCH[4]}" description="${BASH_REMATCH[5]}"
 
 	if [[ ! -v CFG_TYPES["$type"] ]]; then
-		_err "unknown type '$type'"
+		_err type-enum "$type"
 		_hint "Allowed types: ${!CFG_TYPES[*]}"
 		return 1
 	fi
 
 	[[ -z "$description" || "$description" =~ ^[[:space:]]*$ ]] && {
-		_err "description cannot be empty"
+		_err description-empty
+		return 1
+	}
+
+	local rest="${message#*$'\n'}"
+	[[ "$rest" != "$message" && "${rest%%$'\n'*}" != "" ]] && {
+		_err body-leading-blank
 		return 1
 	}
 
@@ -700,8 +753,8 @@ cmd_lint() {
 		breaking_footer="${CFG_SETTINGS[breaking_footer]:-true}"
 	fi
 
-	[[ "$breaking_footer" == "true" && -n "$breaking" && ! "$message" =~ BREAKING[[:space:]]CHANGE: ]] && {
-		_err "breaking change (!) requires 'BREAKING CHANGE:' footer"
+	[[ "$breaking_footer" == "true" && -n "$breaking" && ! "$message" =~ BREAKING[-\ ]CHANGE: ]] && {
+		_err breaking-footer
 		return 1
 	}
 
@@ -752,13 +805,13 @@ validate_paths_if_needed() {
 	fi
 
 	if [[ "$require_scope" == "true" && -z "$scope" ]]; then
-		_err "scope required"
+		_err scope-required
 		return 1
 	fi
 
 	if [[ "$defined_scope" == "true" && -n "$scope" ]]; then
 		[[ ${#CFG_SCOPES[@]} -eq 0 ]] && {
-			_err "scope '$scope' used but no scopes defined in config"
+			_err scope-missing-config "$scope"
 			return 1
 		}
 		if is_multi_scope "$scope"; then
@@ -777,7 +830,7 @@ validate_paths_if_needed() {
 
 	if [[ -z "$scope" ]]; then
 		if ! validate_strict_no_scope "${files[@]}"; then
-			_err "scope required for scoped files"
+			_err scope-file-required
 			_show_errors "${STRICT_MATCHES[@]}"
 			_hint "Hint: add a scope that matches these files"
 			return 1
@@ -789,13 +842,13 @@ validate_paths_if_needed() {
 
 	if is_multi_scope "$scope"; then
 		[[ "$multi_scope" != "true" ]] && {
-			_err "multi-scope not enabled"
+			_err multi-scope-disabled
 			_hint "Use --multi-scope flag or set multi-scope = true in [settings]"
 			return 1
 		}
 		_check_scopes_exist "$scope" || return 1
 		if ! validate_files_against_scopes "$scope" "${files[@]}"; then
-			_err "files do not match scopes '$scope'"
+			_err files-scopes-mismatch "$scope"
 			_show_errors "${VALIDATION_ERRORS[@]}"
 			return 1
 		fi
@@ -807,7 +860,7 @@ validate_paths_if_needed() {
 		return 1
 	}
 	if ! validate_files_against_scope "$scope" "${files[@]}"; then
-		_err "files do not match scope '$scope'"
+		_err files-scope-mismatch "$scope"
 		_show_errors "${VALIDATION_ERRORS[@]}"
 		return 1
 	fi
@@ -816,6 +869,7 @@ validate_paths_if_needed() {
 # --- begin: scripts/cz/cmd_create.sh ---
 
 
+# --- skipped (already included): scripts/cz/helpers.sh ---
 # --- skipped (already included): scripts/cz/config.sh ---
 
 _gum() { gum "$@" || exit 130; }
@@ -825,8 +879,8 @@ _scope_input_custom() { _gum input --header "Enter scope:" --placeholder "e.g.,
 
 cmd_create() {
 	if ! command -v gum &>/dev/null; then
-		echo "cz: error: gum is required for interactive mode" >&2
-		echo "See: https://github.com/charmbracelet/gum" >&2
+		_err gum-not-found
+		_hint "See: https://github.com/charmbracelet/gum"
 		exit 1
 	fi
 
@@ -899,7 +953,7 @@ cmd_create() {
 	local description=""
 	while [[ -z "$description" ]]; do
 		description=$(_gum input --header "Description (required):" --placeholder "Short summary of the change")
-		[[ -z "$description" ]] && echo "cz: error: description cannot be empty" >&2
+		[[ -z "$description" ]] && _err description-required
 	done
 
 	local body
@@ -910,7 +964,7 @@ cmd_create() {
 		local breaking_explanation=""
 		while [[ -z "$breaking_explanation" ]]; do
 			breaking_explanation=$(_gum write --header "Breaking change explanation (required):" --placeholder "Describe what breaks and how to migrate...")
-			[[ -z "$breaking_explanation" ]] && echo "cz: error: breaking change explanation is required" >&2
+			[[ -z "$breaking_explanation" ]] && _err breaking-explanation
 		done
 		footer="BREAKING CHANGE: $breaking_explanation"
 	else
diff --git a/dist/cz/completions/bash/cz.bash b/dist/cz/completions/bash/cz.bash
index 7b955cb..727fc32 100644
--- a/dist/cz/completions/bash/cz.bash
+++ b/dist/cz/completions/bash/cz.bash
@@ -7,7 +7,7 @@ _cz() {
 	prev="${COMP_WORDS[COMP_CWORD-1]}"
 
 	local commands="create lint parse init hook"
-	local global_opts="-c --config-file -r --require-scope --no-require-scope -d --defined-scope --no-defined-scope -e --enforce-patterns --no-enforce-patterns -m --multi-scope --no-multi-scope --breaking-footer --no-breaking-footer -q --quiet -h --help -V --version"
+	local global_opts="-c --config-file -r --require-scope --no-require-scope -d --defined-scope --no-defined-scope -e --enforce-patterns --no-enforce-patterns -m --multi-scope --no-multi-scope -b --breaking-footer --no-breaking-footer -q --quiet -h --help -V --version"
 
 	# Complete config file path after -c/--config-file
 	if [[ "$prev" == "-c" || "$prev" == "--config-file" ]]; then
diff --git a/dist/cz/completions/zsh/_cz b/dist/cz/completions/zsh/_cz
index b23af50..026482f 100644
--- a/dist/cz/completions/zsh/_cz
+++ b/dist/cz/completions/zsh/_cz
@@ -16,8 +16,8 @@ _cz() {
 		'(-e --enforce-patterns --no-enforce-patterns)--no-enforce-patterns[Disable pattern enforcement]' \
 		'(-m --multi-scope --no-multi-scope)'{-m,--multi-scope}'[Allow multiple scopes]' \
 		'(-m --multi-scope --no-multi-scope)--no-multi-scope[Disallow multiple scopes]' \
-		'(--breaking-footer --no-breaking-footer)--breaking-footer[Require BREAKING CHANGE footer]' \
-		'(--breaking-footer --no-breaking-footer)--no-breaking-footer[Allow breaking changes without footer]' \
+		'(-b --breaking-footer --no-breaking-footer)'{-b,--breaking-footer}'[Require BREAKING CHANGE footer]' \
+		'(-b --breaking-footer --no-breaking-footer)--no-breaking-footer[Allow breaking changes without footer]' \
 		'(-q --quiet)'{-q,--quiet}'[Suppress warnings and non-essential output]' \
 		'1:command:->commands' \
 		'*::arg:->args'
diff --git a/dist/cz/man/man1/cz.1 b/dist/cz/man/man1/cz.1
index 64db2ca..6eaf3da 100644
--- a/dist/cz/man/man1/cz.1
+++ b/dist/cz/man/man1/cz.1
@@ -31,7 +31,7 @@
 cz \- conventional commit message builder
 .SH "SYNOPSIS"
 .sp
-\fBcz\fP [\fB\-r\fP | \fB\-\-no\-require\-scope\fP] [\fB\-d\fP | \fB\-\-no\-defined\-scope\fP] [\fB\-e\fP | \fB\-\-no\-enforce\-patterns\fP] [\fB\-m\fP | \fB\-\-no\-multi\-scope\fP] [\fB\-\-breaking\-footer\fP | \fB\-\-no\-breaking\-footer\fP] [\fB\-q\fP] [\fB\-c\fP \fIFILE\fP] [\fISUBCOMMAND\fP]
+\fBcz\fP [\fB\-r\fP | \fB\-\-no\-require\-scope\fP] [\fB\-d\fP | \fB\-\-no\-defined\-scope\fP] [\fB\-e\fP | \fB\-\-no\-enforce\-patterns\fP] [\fB\-m\fP | \fB\-\-no\-multi\-scope\fP] [\fB\-b\fP | \fB\-\-no\-breaking\-footer\fP] [\fB\-q\fP] [\fB\-c\fP \fIFILE\fP] [\fISUBCOMMAND\fP]
 .sp
 \fBcz\fP \fBcreate\fP
 .br
@@ -155,10 +155,11 @@ Allow multiple scopes like \f(CRfeat(api,db):\fP. Overrides \f(CRmulti\-scope\fP
 Disallow multiple scopes. Overrides \f(CRmulti\-scope\fP config.
 .RE
 .sp
-\fB\-\-breaking\-footer\fP
+\fB\-b\fP, \fB\-\-breaking\-footer\fP
 .RS 4
-Require a \f(CRBREAKING CHANGE:\fP footer when the commit has a breaking change
-indicator (\f(CR!\fP). Overrides \f(CRbreaking\-footer\fP config. Default when unset: true.
+Require a \f(CRBREAKING CHANGE:\fP (or \f(CRBREAKING\-CHANGE:\fP) footer when the commit
+has a breaking change indicator (\f(CR!\fP). Overrides \f(CRbreaking\-footer\fP config.
+Default when unset: true.
 .RE
 .sp
 \fB\-\-no\-breaking\-footer\fP
@@ -285,10 +286,10 @@ Scope required and must match patterns
 T}
 T{
 .sp
-\fB\-\-breaking\-footer\fP
+\fB\-b\fP / \fB\-\-breaking\-footer\fP
 T}:T{
 .sp
-Breaking \f(CR!\fP requires \f(CRBREAKING CHANGE:\fP footer (default)
+Breaking \f(CR!\fP requires \f(CRBREAKING CHANGE:\fP or \f(CRBREAKING\-CHANGE:\fP footer (default)
 T}
 T{
 .sp
diff --git a/dist/cz/man/man5/gitcommitizen.5 b/dist/cz/man/man5/gitcommitizen.5
index 87bf263..9f54663 100644
--- a/dist/cz/man/man5/gitcommitizen.5
+++ b/dist/cz/man/man5/gitcommitizen.5
@@ -315,6 +315,97 @@ Scopes may include letters, numbers, dashes, underscores, and \f(CR@\fP (e.g., \
 .\}
 Glob patterns follow standard shell globbing with \f(CR**\fP for recursive matching.
 .RE
+.SH "SPEC COMPLIANCE"
+.sp
+Validation rules from \c
+.URL "https://www.conventionalcommits.org/en/v1.0.0/" "Conventional Commits v1.0.0" ":"
+.TS
+allbox tab(:);
+ltB ltB ltB.
+T{
+.sp
+Rule
+T}:T{
+.sp
+Enforcement
+T}:T{
+.sp
+Ref
+T}
+.T&
+lt lt lt.
+T{
+.sp
+Type prefix required
+T}:T{
+.sp
+Always (lint, create)
+T}:T{
+.sp
+§1
+T}
+T{
+.sp
+Description required
+T}:T{
+.sp
+Always
+T}:T{
+.sp
+§5
+T}
+T{
+.sp
+Blank line before body
+T}:T{
+.sp
+Always (lint)
+T}:T{
+.sp
+§6
+T}
+T{
+.sp
+BREAKING CHANGE uppercase
+T}:T{
+.sp
+Always (lint)
+T}:T{
+.sp
+§15
+T}
+T{
+.sp
+BREAKING\-CHANGE synonym
+T}:T{
+.sp
+Accepted in footers
+T}:T{
+.sp
+§16
+T}
+T{
+.sp
+Scope defined/required
+T}:T{
+.sp
+Configurable (\f(CR\-r\fP, \f(CR\-d\fP, \f(CR\-e\fP)
+T}:T{
+.sp
+—
+T}
+T{
+.sp
+Breaking footer required
+T}:T{
+.sp
+Configurable (\f(CR\-b\fP, \f(CR\-\-breaking\-footer\fP)
+T}:T{
+.sp
+—
+T}
+.TE
+.sp
 .SH "SEE ALSO"
 .sp
 git\-commit(1)
diff --git a/scripts/cz/cmd_create.sh b/scripts/cz/cmd_create.sh
index b852631..ed2bd2e 100644
--- a/scripts/cz/cmd_create.sh
+++ b/scripts/cz/cmd_create.sh
@@ -2,6 +2,8 @@
 
 # cz create - compose a commit message interactively
 
+# @bundle source
+. ./helpers.sh
 # @bundle source
 . ./config.sh
 
@@ -15,8 +17,8 @@ _scope_input_custom() { _gum input --header "Enter scope:" --placeholder "e.g.,
 cmd_create() {
 	# Check gum dependency
 	if ! command -v gum &>/dev/null; then
-		echo "cz: error: gum is required for interactive mode" >&2
-		echo "See: https://github.com/charmbracelet/gum" >&2
+		_err gum-not-found
+		_hint "See: https://github.com/charmbracelet/gum"
 		exit 1
 	fi
 
@@ -102,7 +104,7 @@ cmd_create() {
 	local description=""
 	while [[ -z "$description" ]]; do
 		description=$(_gum input --header "Description (required):" --placeholder "Short summary of the change")
-		[[ -z "$description" ]] && echo "cz: error: description cannot be empty" >&2
+		[[ -z "$description" ]] && _err description-required
 	done
 
 	# Get body (optional)
@@ -115,7 +117,7 @@ cmd_create() {
 		local breaking_explanation=""
 		while [[ -z "$breaking_explanation" ]]; do
 			breaking_explanation=$(_gum write --header "Breaking change explanation (required):" --placeholder "Describe what breaks and how to migrate...")
-			[[ -z "$breaking_explanation" ]] && echo "cz: error: breaking change explanation is required" >&2
+			[[ -z "$breaking_explanation" ]] && _err breaking-explanation
 		done
 		footer="BREAKING CHANGE: $breaking_explanation"
 	else
diff --git a/scripts/cz/cmd_hook.sh b/scripts/cz/cmd_hook.sh
index 9d4bb48..e0191c8 100644
--- a/scripts/cz/cmd_hook.sh
+++ b/scripts/cz/cmd_hook.sh
@@ -2,13 +2,16 @@
 
 # cz hook - manage the commit-msg git hook
 
+# @bundle source
+. ./helpers.sh
+
 cmd_hook() {
 	local action="${1:-status}"
 
 	# Find git directory
 	local git_dir
 	git_dir="$(git rev-parse --git-dir 2>/dev/null)" || {
-		echo "cz: error: not a git repository" >&2
+		_err not-git-repo
 		return 1
 	}
 
@@ -26,8 +29,8 @@ cmd_hook() {
 			hook_status "$hook_path" "$hook_marker"
 			;;
 		*)
-			echo "cz: error: unknown hook action '$action'" >&2
-			echo "Usage: cz hook [install|uninstall|status]" >&2
+			_err hook-action-unknown "$action"
+			_hint "Usage: cz hook [install|uninstall|status]"
 			return 2
 			;;
 	esac
@@ -42,8 +45,8 @@ hook_install() {
 			echo "cz: hook already installed"
 			return 0
 		else
-			echo "cz: error: existing commit-msg hook found" >&2
-			echo "Remove it manually or add 'cz lint < \"\$1\"' to it" >&2
+			_err hook-exists
+			_hint "Remove it manually or add 'cz lint < \"\$1\"' to it"
 			return 1
 		fi
 	fi
@@ -77,7 +80,7 @@ hook_uninstall() {
 	fi
 
 	if ! grep -q "$hook_marker" "$hook_path" 2>/dev/null; then
-		echo "cz: error: commit-msg hook was not installed by cz" >&2
+		_err hook-foreign
 		return 1
 	fi
 
diff --git a/scripts/cz/cmd_init.sh b/scripts/cz/cmd_init.sh
index d2e6526..ea5893e 100644
--- a/scripts/cz/cmd_init.sh
+++ b/scripts/cz/cmd_init.sh
@@ -2,6 +2,8 @@
 
 # cz init - generate a starter .gitcommitizen file
 
+# @bundle source
+. ./helpers.sh
 # @bundle source
 . ./config_defaults.sh
 
@@ -16,7 +18,7 @@ cmd_init() {
 
 	# Write to file
 	if [[ -f "$OUTPUT_FILE" && -z "${FORCE:-}" ]]; then
-		echo "cz: error: '$OUTPUT_FILE' already exists (use -f to overwrite)" >&2
+		_err file-exists "$OUTPUT_FILE"
 		return 1
 	fi
 
diff --git a/scripts/cz/cmd_lint.sh b/scripts/cz/cmd_lint.sh
index 3a4a485..000b065 100644
--- a/scripts/cz/cmd_lint.sh
+++ b/scripts/cz/cmd_lint.sh
@@ -7,11 +7,8 @@
 # @bundle source
 . ./path_validator.sh
 
-# Output helpers - respect QUIET flag
-_err() { [[ -n "${QUIET:-}" ]] || echo "cz: error: $1" >&2; }
-_hint() { [[ -n "${QUIET:-}" ]] || echo "$1" >&2; }
 _scope_err() {
-	_err "unknown scope '$1'"
+	_err scope-enum "$1"
 	_hint "Defined scopes: ${!CFG_SCOPES[*]}"
 }
 _show_errors() {
@@ -41,7 +38,7 @@ cmd_lint() {
 	message="$(cat)"
 
 	[[ -z "$message" ]] && {
-		_err "empty commit message"
+		_err empty-message
 		return 1
 	}
 
@@ -54,8 +51,9 @@ cmd_lint() {
 	local pattern='^([a-z]+)(\(([a-zA-Z0-9_@/,*-]+)\))?(!)?: (.+)$'
 
 	if [[ ! "$first_line" =~ $pattern ]]; then
-		_err "invalid commit format"
-		_hint "Expected: <type>[(scope)]: <description>"
+		# Spec #1: commits MUST be prefixed with a type, followed by colon and space
+		_err header-format
+		_hint "Expected: <type>[(<scope>)][!]: <description>"
 		return 1
 	fi
 
@@ -64,14 +62,22 @@ cmd_lint() {
 
 	# Validate type
 	if [[ ! -v CFG_TYPES["$type"] ]]; then
-		_err "unknown type '$type'"
+		_err type-enum "$type"
 		_hint "Allowed types: ${!CFG_TYPES[*]}"
 		return 1
 	fi
 
-	# Validate description is not empty
+	# Spec #5: description MUST immediately follow the colon and space
 	[[ -z "$description" || "$description" =~ ^[[:space:]]*$ ]] && {
-		_err "description cannot be empty"
+		_err description-empty
+		return 1
+	}
+
+	# Validate blank line after subject when body/footer present
+	# Spec: "body MUST begin one blank line after the description"
+	local rest="${message#*$'\n'}"
+	[[ "$rest" != "$message" && "${rest%%$'\n'*}" != "" ]] && {
+		_err body-leading-blank
 		return 1
 	}
 
@@ -84,9 +90,12 @@ cmd_lint() {
 		breaking_footer="${CFG_SETTINGS[breaking_footer]:-true}"
 	fi
 
-	# Validate breaking change has BREAKING CHANGE footer
-	[[ "$breaking_footer" == "true" && -n "$breaking" && ! "$message" =~ BREAKING[[:space:]]CHANGE: ]] && {
-		_err "breaking change (!) requires 'BREAKING CHANGE:' footer"
+	# Spec #13: if included in the type/scope prefix, breaking changes MUST
+	# be indicated by a BREAKING CHANGE footer
+	# Spec #16: BREAKING-CHANGE MUST be synonymous with BREAKING CHANGE
+	# Spec #15: BREAKING CHANGE MUST be uppercase
+	[[ "$breaking_footer" == "true" && -n "$breaking" && ! "$message" =~ BREAKING[-\ ]CHANGE: ]] && {
+		_err breaking-footer
 		return 1
 	}
 
@@ -149,14 +158,14 @@ validate_paths_if_needed() {
 
 	# -r: require scope to be present
 	if [[ "$require_scope" == "true" && -z "$scope" ]]; then
-		_err "scope required"
+		_err scope-required
 		return 1
 	fi
 
 	# -d: validate scope exists in config (if scope provided)
 	if [[ "$defined_scope" == "true" && -n "$scope" ]]; then
 		[[ ${#CFG_SCOPES[@]} -eq 0 ]] && {
-			_err "scope '$scope' used but no scopes defined in config"
+			_err scope-missing-config "$scope"
 			return 1
 		}
 		if is_multi_scope "$scope"; then
@@ -178,7 +187,7 @@ validate_paths_if_needed() {
 	# No scope provided - check if files match any pattern
 	if [[ -z "$scope" ]]; then
 		if ! validate_strict_no_scope "${files[@]}"; then
-			_err "scope required for scoped files"
+			_err scope-file-required
 			_show_errors "${STRICT_MATCHES[@]}"
 			_hint "Hint: add a scope that matches these files"
 			return 1
@@ -192,14 +201,14 @@ validate_paths_if_needed() {
 	# Multi-scope validation
 	if is_multi_scope "$scope"; then
 		[[ "$multi_scope" != "true" ]] && {
-			_err "multi-scope not enabled"
+			_err multi-scope-disabled
 			_hint "Use --multi-scope flag or set multi-scope = true in [settings]"
 			return 1
 		}
 		# Validate scopes exist
 		_check_scopes_exist "$scope" || return 1
 		if ! validate_files_against_scopes "$scope" "${files[@]}"; then
-			_err "files do not match scopes '$scope'"
+			_err files-scopes-mismatch "$scope"
 			_show_errors "${VALIDATION_ERRORS[@]}"
 			return 1
 		fi
@@ -212,7 +221,7 @@ validate_paths_if_needed() {
 		return 1
 	}
 	if ! validate_files_against_scope "$scope" "${files[@]}"; then
-		_err "files do not match scope '$scope'"
+		_err files-scope-mismatch "$scope"
 		_show_errors "${VALIDATION_ERRORS[@]}"
 		return 1
 	fi
diff --git a/scripts/cz/completions/_cz b/scripts/cz/completions/_cz
index b23af50..026482f 100644
--- a/scripts/cz/completions/_cz
+++ b/scripts/cz/completions/_cz
@@ -16,8 +16,8 @@ _cz() {
 		'(-e --enforce-patterns --no-enforce-patterns)--no-enforce-patterns[Disable pattern enforcement]' \
 		'(-m --multi-scope --no-multi-scope)'{-m,--multi-scope}'[Allow multiple scopes]' \
 		'(-m --multi-scope --no-multi-scope)--no-multi-scope[Disallow multiple scopes]' \
-		'(--breaking-footer --no-breaking-footer)--breaking-footer[Require BREAKING CHANGE footer]' \
-		'(--breaking-footer --no-breaking-footer)--no-breaking-footer[Allow breaking changes without footer]' \
+		'(-b --breaking-footer --no-breaking-footer)'{-b,--breaking-footer}'[Require BREAKING CHANGE footer]' \
+		'(-b --breaking-footer --no-breaking-footer)--no-breaking-footer[Allow breaking changes without footer]' \
 		'(-q --quiet)'{-q,--quiet}'[Suppress warnings and non-essential output]' \
 		'1:command:->commands' \
 		'*::arg:->args'
diff --git a/scripts/cz/completions/cz.bash b/scripts/cz/completions/cz.bash
index 7b955cb..727fc32 100644
--- a/scripts/cz/completions/cz.bash
+++ b/scripts/cz/completions/cz.bash
@@ -7,7 +7,7 @@ _cz() {
 	prev="${COMP_WORDS[COMP_CWORD-1]}"
 
 	local commands="create lint parse init hook"
-	local global_opts="-c --config-file -r --require-scope --no-require-scope -d --defined-scope --no-defined-scope -e --enforce-patterns --no-enforce-patterns -m --multi-scope --no-multi-scope --breaking-footer --no-breaking-footer -q --quiet -h --help -V --version"
+	local global_opts="-c --config-file -r --require-scope --no-require-scope -d --defined-scope --no-defined-scope -e --enforce-patterns --no-enforce-patterns -m --multi-scope --no-multi-scope -b --breaking-footer --no-breaking-footer -q --quiet -h --help -V --version"
 
 	# Complete config file path after -c/--config-file
 	if [[ "$prev" == "-c" || "$prev" == "--config-file" ]]; then
diff --git a/scripts/cz/config.sh b/scripts/cz/config.sh
index 2436c59..3b18804 100644
--- a/scripts/cz/config.sh
+++ b/scripts/cz/config.sh
@@ -2,6 +2,8 @@
 
 # Find and load .gitcommitizen configuration
 
+# @bundle source
+. ./helpers.sh
 # @bundle source
 . ./config_defaults.sh
 # @bundle source
@@ -40,7 +42,7 @@ find_config() {
 load_config() {
 	if [[ -n "$CONFIG_FILE" ]]; then
 		if [[ ! -f "$CONFIG_FILE" ]]; then
-			echo "cz: error: config file not found: $CONFIG_FILE" >&2
+			_err config-not-found "$CONFIG_FILE"
 			exit 1
 		fi
 
@@ -48,7 +50,7 @@ load_config() {
 
 		# If no types defined, use default types but preserve settings/scopes
 		if [[ ${#CFG_TYPES[@]} -eq 0 ]]; then
-			[[ -z "${QUIET:-}" ]] && echo "cz: warning: no [types] in $CONFIG_FILE, using defaults" >&2
+			_hint "cz: warning: no [types] in $CONFIG_FILE, using defaults"
 			_set_default_types
 		fi
 	else
diff --git a/scripts/cz/docs/cz.adoc b/scripts/cz/docs/cz.adoc
index dd028d5..bb43039 100644
--- a/scripts/cz/docs/cz.adoc
+++ b/scripts/cz/docs/cz.adoc
@@ -13,7 +13,7 @@ cz - conventional commit message builder
 
 == SYNOPSIS
 
-*cz* [*-r* | *--no-require-scope*] [*-d* | *--no-defined-scope*] [*-e* | *--no-enforce-patterns*] [*-m* | *--no-multi-scope*] [*--breaking-footer* | *--no-breaking-footer*] [*-q*] [*-c* _FILE_] [_SUBCOMMAND_]
+*cz* [*-r* | *--no-require-scope*] [*-d* | *--no-defined-scope*] [*-e* | *--no-enforce-patterns*] [*-m* | *--no-multi-scope*] [*-b* | *--no-breaking-footer*] [*-q*] [*-c* _FILE_] [_SUBCOMMAND_]
 
 *cz* *create* +
 *cz* *lint* [*-p* _PATHS_] +
@@ -106,9 +106,10 @@ in a terminal, or *lint* mode if receiving input on standard input.
 *--no-multi-scope*::
   Disallow multiple scopes. Overrides `multi-scope` config.
 
-*--breaking-footer*::
-  Require a `BREAKING CHANGE:` footer when the commit has a breaking change
-  indicator (`!`). Overrides `breaking-footer` config. Default when unset: true.
+*-b*, *--breaking-footer*::
+  Require a `BREAKING CHANGE:` (or `BREAKING-CHANGE:`) footer when the commit
+  has a breaking change indicator (`!`). Overrides `breaking-footer` config.
+  Default when unset: true.
 
 *--no-breaking-footer*::
   Allow breaking changes without a `BREAKING CHANGE:` footer. Overrides
@@ -172,8 +173,8 @@ The *-r*, *-d*, and *-e* flags affect the *lint* command:
 |*-r -e*
 |Scope required and must match patterns
 
-|*--breaking-footer*
-|Breaking `!` requires `BREAKING CHANGE:` footer (default)
+|*-b* / *--breaking-footer*
+|Breaking `!` requires `BREAKING CHANGE:` or `BREAKING-CHANGE:` footer (default)
 
 |*--no-breaking-footer*
 |Breaking `!` allowed without footer
diff --git a/scripts/cz/docs/gitcommitizen.adoc b/scripts/cz/docs/gitcommitizen.adoc
index ad774ea..f8bd144 100644
--- a/scripts/cz/docs/gitcommitizen.adoc
+++ b/scripts/cz/docs/gitcommitizen.adoc
@@ -135,6 +135,43 @@ Place **.gitcommitizen** in the root of a Git repository.
 * Scopes may include letters, numbers, dashes, underscores, and `@` (e.g., `@types/node`).
 * Glob patterns follow standard shell globbing with `**` for recursive matching.
 
+== SPEC COMPLIANCE
+
+Validation rules from https://www.conventionalcommits.org/en/v1.0.0/[Conventional Commits v1.0.0]:
+
+[cols="2,3,1", options="header"]
+|===
+|Rule |Enforcement |Ref
+
+|Type prefix required
+|Always (lint, create)
+|§1
+
+|Description required
+|Always
+|§5
+
+|Blank line before body
+|Always (lint)
+|§6
+
+|BREAKING CHANGE uppercase
+|Always (lint)
+|§15
+
+|BREAKING-CHANGE synonym
+|Accepted in footers
+|§16
+
+|Scope defined/required
+|Configurable (`-r`, `-d`, `-e`)
+|—
+
+|Breaking footer required
+|Configurable (`-b`, `--breaking-footer`)
+|—
+|===
+
 == SEE ALSO
 
 git-commit(1)::
diff --git a/scripts/cz/error_codes.sh b/scripts/cz/error_codes.sh
new file mode 100644
index 0000000..9e43150
--- /dev/null
+++ b/scripts/cz/error_codes.sh
@@ -0,0 +1,33 @@
+# shellcheck shell=bash
+
+# Error code registry - centralized error messages for cz
+# Each code maps to a printf format string
+# Usage: _err <code> [args...]
+
+# shellcheck disable=SC2034 # ERR_CODES is used by _err in helpers.sh
+# @start-kcov-exclude - static data table
+declare -gA ERR_CODES=(
+	["empty-message"]="empty commit message"
+	["header-format"]="commits MUST be prefixed with a type, followed by a colon and space"
+	["type-enum"]="unknown type '%s'"
+	["description-empty"]="description MUST immediately follow the colon and space"
+	["body-leading-blank"]="body MUST begin one blank line after the description"
+	["breaking-footer"]="if included in the type/scope prefix, breaking changes MUST be indicated by a BREAKING CHANGE footer"
+	["scope-required"]="scope required"
+	["scope-enum"]="unknown scope '%s'"
+	["scope-missing-config"]="scope '%s' used but no scopes defined in config"
+	["scope-file-required"]="scope required for scoped files"
+	["multi-scope-disabled"]="multi-scope not enabled"
+	["files-scope-mismatch"]="files do not match scope '%s'"
+	["files-scopes-mismatch"]="files do not match scopes '%s'"
+	["config-not-found"]="config file not found: %s"
+	["gum-not-found"]="gum is required for interactive mode"
+	["description-required"]="description MUST NOT be empty"
+	["breaking-explanation"]="breaking change explanation is required"
+	["file-exists"]="'%s' already exists (use -f to overwrite)"
+	["not-git-repo"]="not a git repository"
+	["hook-action-unknown"]="unknown hook action '%s'"
+	["hook-exists"]="existing commit-msg hook found"
+	["hook-foreign"]="commit-msg hook was not installed by cz"
+)
+# @end-kcov-exclude
diff --git a/scripts/cz/helpers.sh b/scripts/cz/helpers.sh
index 97edc3b..41a75a8 100644
--- a/scripts/cz/helpers.sh
+++ b/scripts/cz/helpers.sh
@@ -2,6 +2,25 @@
 
 # Shared helper functions for cz
 
+# @bundle source
+. ./error_codes.sh
+
+# Output helpers - respect QUIET flag
+_err() {
+	[[ -n "${QUIET:-}" ]] && return
+	local code="$1"
+	shift
+	local msg="${ERR_CODES[$code]}"
+	if [[ -n "$msg" ]]; then
+		# shellcheck disable=SC2059 # intentional printf format from registry
+		printf -v msg "$msg" "$@"
+		echo "cz: error: $msg [$code]" >&2
+	else
+		echo "cz: error: $code $* [unknown]" >&2
+	fi
+}
+_hint() { [[ -n "${QUIET:-}" ]] || echo "$1" >&2; }
+
 # Trim leading/trailing whitespace from variable
 # Usage: _trim varname
 _trim() {
diff --git a/scripts/cz/main_spec.sh b/scripts/cz/main_spec.sh
index c23e62d..dca6a36 100644
--- a/scripts/cz/main_spec.sh
+++ b/scripts/cz/main_spec.sh
@@ -97,6 +97,56 @@ Describe 'cz'
 			End
 		End
 
+		#───────────────────────────────────────────────────────────
+		# Body blank line (spec: body MUST begin one blank line)
+		#───────────────────────────────────────────────────────────
+		Describe 'body blank line'
+			It 'accepts single-line message (no body)'
+				Data "docs: correct spelling of CHANGELOG"
+				When run script "$BIN" lint
+				The status should be success
+			End
+
+			It 'accepts message with blank line before body'
+				Data
+					#|fix: prevent racing of requests
+					#|
+					#|Introduce a request id and a reference to latest request. Dismiss
+					#|incoming responses other than from latest request.
+				End
+				When run script "$BIN" lint
+				The status should be success
+			End
+
+			It 'rejects body without blank line separator'
+				Data
+					#|fix: prevent racing of requests
+					#|Introduce a request id and a reference to latest request.
+				End
+				When run script "$BIN" lint
+				The status should be failure
+				The stderr should include "[body-leading-blank]"
+			End
+
+			It 'rejects footer without blank line separator'
+				Data
+					#|feat: allow provided config object to extend other configs
+					#|BREAKING CHANGE: `extends` key in config file is now used for extending other config files
+				End
+				When run script "$BIN" lint
+				The status should be failure
+				The stderr should include "[body-leading-blank]"
+			End
+
+			It 'accepts message with only a trailing newline'
+				Data
+					#|docs: correct spelling of CHANGELOG
+				End
+				When run script "$BIN" lint
+				The status should be success
+			End
+		End
+
 		#───────────────────────────────────────────────────────────
 		# Invalid conventional commits
 		#───────────────────────────────────────────────────────────
@@ -105,70 +155,70 @@ Describe 'cz'
 				Data ""
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "empty commit message"
+				The stderr should include "[empty-message]"
 			End
 
 			It 'rejects whitespace-only message'
 				Data "   "
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects missing colon'
 				Data "feat add feature"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects missing description after colon'
 				Data "feat:"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects missing description after colon and space'
 				Data "feat: "
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects unknown type'
 				Data "unknown: some change"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "unknown type"
+				The stderr should include "[type-enum]"
 			End
 
 			It 'rejects uppercase type'
 				Data "FEAT: add feature"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects breaking ! without BREAKING CHANGE footer'
 				Data "feat!: breaking change"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "BREAKING CHANGE:"
+				The stderr should include "[breaking-footer]"
 			End
 
 			It 'rejects empty scope'
 				Data "feat(): add feature"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "invalid commit format"
+				The stderr should include "[header-format]"
 			End
 
 			It 'rejects whitespace-only description'
 				Data "feat:    "
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "description cannot be empty"
+				The stderr should include "[description-empty]"
 			End
 		End
 
@@ -202,7 +252,7 @@ EOF
 				Data "feat: not in config"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "unknown type"
+				The stderr should include "[type-enum]"
 			End
 
 			It 'uses --config-file option'
@@ -229,8 +279,8 @@ EOF
 				Data "feat: something"
 				When run script "$BIN" --config-file nonexistent.ini lint
 				The status should be failure
-				The stderr should include "config file not found"
 				The stderr should include "nonexistent.ini"
+				The stderr should include "[config-not-found]"
 			End
 
 			It 'handles config with only scopes (uses default types)'
@@ -341,7 +391,7 @@ EOF
 				Data "feat(api): add endpoint"
 				When run script "$BIN" -e lint --paths "src/ui/button.tsx"
 				The status should be failure
-				The stderr should include "does not match scope"
+				The stderr should include "[files-scope-mismatch]"
 			End
 
 			It 'fails when some files do not match scope'
@@ -394,7 +444,7 @@ EOF
 				Data "feat(scripts): update script"
 				When run script "$BIN" -e lint --paths "scripts/nested/main.sh"
 				The status should be failure
-				The stderr should include "does not match scope"
+				The stderr should include "[files-scope-mismatch]"
 			End
 
 			It 'matches multi-pattern scope (first pattern)'
@@ -472,7 +522,7 @@ EOF
 				Data "feat(api,ui): cross-cutting change"
 				When run script "$BIN" -e lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "multi-scope not enabled"
+				The stderr should include "[multi-scope-disabled]"
 			End
 
 			It 'rejects multi-scope by default when validating files'
@@ -487,7 +537,7 @@ EOF
 				Data "feat(api,ui): cross-cutting change"
 				When run script "$BIN" -e lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "multi-scope not enabled"
+				The stderr should include "[multi-scope-disabled]"
 			End
 
 			It 'rejects multi-scope with unknown scope'
@@ -504,7 +554,7 @@ EOF
 				Data "feat(api,unknown): change"
 				When run script "$BIN" -e lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 			End
 
 			It '--multi-scope flag enables multi-scope without config'
@@ -536,7 +586,7 @@ EOF
 				Data "feat(api,ui): cross-cutting change"
 				When run script "$BIN" --no-multi-scope -e lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "multi-scope not enabled"
+				The stderr should include "[multi-scope-disabled]"
 			End
 
 			It '-m shorthand enables multi-scope'
@@ -579,7 +629,7 @@ EOF
 				Data "feat(api,ui): cross-cutting change"
 				When run script "$BIN" -m -e lint --paths "src/api/handler.go src/other/file.txt"
 				The status should be failure
-				The stderr should include "does not match"
+				The stderr should include "[files-scopes-mismatch]"
 			End
 		End
 
@@ -598,7 +648,7 @@ EOF
 				Data "feat(unknown): add feature"
 				When run script "$BIN" -d lint
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 			End
 
 			It 'accepts defined scope when -d is set'
@@ -635,7 +685,7 @@ EOF
 				Data "feat(anything): add feature"
 				When run script "$BIN" -d lint
 				The status should be failure
-				The stderr should include "no scopes defined"
+				The stderr should include "[scope-missing-config]"
 			End
 
 			It '--no-defined-scope overrides config'
@@ -668,7 +718,7 @@ EOF
 				Data "feat(unknown): add feature"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 			End
 		End
 
@@ -684,7 +734,7 @@ EOF
 				Data "feat: add feature"
 				When run script "$BIN" -r lint
 				The status should be failure
-				The stderr should include "scope required"
+				The stderr should include "[scope-required]"
 			End
 
 			It 'accepts scope when -r is set'
@@ -745,7 +795,7 @@ EOF
 				Data "feat(api): add endpoint"
 				When run script "$BIN" -e lint --paths "src/ui/button.tsx"
 				The status should be failure
-				The stderr should include "does not match scope"
+				The stderr should include "[files-scope-mismatch]"
 			End
 
 			It 'passes when scope matches files with -e'
@@ -758,7 +808,7 @@ EOF
 				Data "feat: add feature"
 				When run script "$BIN" -e lint --paths "src/api/handler.go"
 				The status should be failure
-				The stderr should include "scope required"
+				The stderr should include "[scope-file-required]"
 			End
 
 			It 'allows no scope for unscoped files when -e is set'
@@ -771,14 +821,14 @@ EOF
 				Data "feat(unknown): add feature"
 				When run script "$BIN" -e lint --paths "other/file.txt"
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 			End
 
 			It '-e with unknown scope shows defined scopes hint'
 				Data "feat(unknown): add feature"
 				When run script "$BIN" -e lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 				The stderr should include "api"
 				The stderr should include "ui"
 			End
@@ -813,7 +863,7 @@ EOF
 				Data "feat(api): add endpoint"
 				When run script "$BIN" lint --paths "src/ui/button.tsx"
 				The status should be failure
-				The stderr should include "does not match scope"
+				The stderr should include "[files-scope-mismatch]"
 			End
 
 			It 'config enforce-patterns without defined-scope rejects unknown scope'
@@ -830,7 +880,7 @@ EOF
 				Data "feat(unknown): add feature"
 				When run script "$BIN" lint --paths "src/api/x.go"
 				The status should be failure
-				The stderr should include "unknown scope"
+				The stderr should include "[scope-enum]"
 			End
 		End
 
@@ -839,7 +889,7 @@ EOF
 				Data "feat!: breaking change"
 				When run script "$BIN" lint
 				The status should be failure
-				The stderr should include "breaking change (!) requires 'BREAKING CHANGE:' footer"
+				The stderr should include "[breaking-footer]"
 			End
 
 			It 'allows breaking change without footer when --no-breaking-footer is set'
@@ -852,7 +902,7 @@ EOF
 				Data "feat!: breaking change"
 				When run script "$BIN" --breaking-footer lint
 				The status should be failure
-				The stderr should include "breaking change (!) requires 'BREAKING CHANGE:' footer"
+				The stderr should include "[breaking-footer]"
 			End
 
 			It 'accepts breaking change with footer when --breaking-footer is set'
@@ -899,7 +949,7 @@ EOF
 				Data "feat!: breaking change"
 				When run script "$BIN" --breaking-footer lint
 				The status should be failure
-				The stderr should include "breaking change (!) requires 'BREAKING CHANGE:' footer"
+				The stderr should include "[breaking-footer]"
 			End
 
 			It 'has no effect on non-breaking commits'
@@ -907,6 +957,48 @@ EOF
 				When run script "$BIN" --no-breaking-footer lint
 				The status should be success
 			End
+
+			It 'accepts BREAKING-CHANGE footer as synonym for BREAKING CHANGE'
+				Data
+					#|feat!: breaking change
+					#|
+					#|BREAKING-CHANGE: this is breaking
+				End
+				When run script "$BIN" lint
+				The status should be success
+			End
+
+			It 'accepts BREAKING-CHANGE footer with --breaking-footer flag'
+				Data
+					#|feat!: breaking change
+					#|
+					#|BREAKING-CHANGE: this is breaking
+				End
+				When run script "$BIN" --breaking-footer lint
+				The status should be success
+			End
+
+			It 'rejects BREAKING!CHANGE as footer (not a valid separator)'
+				Data
+					#|feat!: breaking change
+					#|
+					#|BREAKING!CHANGE: this is breaking
+				End
+				When run script "$BIN" lint
+				The status should be failure
+				The stderr should include "[breaking-footer]"
+			End
+
+			It 'rejects lowercase breaking change footer'
+				Data
+					#|feat!: breaking change
+					#|
+					#|breaking change: this is breaking
+				End
+				When run script "$BIN" lint
+				The status should be failure
+				The stderr should include "[breaking-footer]"
+			End
 		End
 
 		#───────────────────────────────────────────────────────────
@@ -993,7 +1085,7 @@ EOF
 				touch .gitcommitizen
 				When run script "$BIN" init -o .gitcommitizen
 				The status should be failure
-				The stderr should include "already exists"
+				The stderr should include "[file-exists]"
 			End
 
 			It '-f overwrites existing file'
@@ -1080,7 +1172,7 @@ EOF
 				printf '#!/bin/sh\necho "other"\n' > .git/hooks/commit-msg
 				When run script "$BIN" hook install
 				The status should be failure
-				The stderr should include "existing commit-msg hook"
+				The stderr should include "[hook-exists]"
 			End
 		End
 
@@ -1104,7 +1196,7 @@ EOF
 				printf '#!/bin/sh\necho "other"\n' > .git/hooks/commit-msg
 				When run script "$BIN" hook uninstall
 				The status should be failure
-				The stderr should include "not installed by cz"
+				The stderr should include "[hook-foreign]"
 			End
 		End
 
@@ -1113,28 +1205,28 @@ EOF
 				rm -rf .git
 				When run script "$BIN" hook status
 				The status should be failure
-				The stderr should include "not a git repository"
+				The stderr should include "[not-git-repo]"
 			End
 
 			It 'install errors outside git repo'
 				rm -rf .git
 				When run script "$BIN" hook install
 				The status should be failure
-				The stderr should include "not a git repository"
+				The stderr should include "[not-git-repo]"
 			End
 
 			It 'uninstall errors outside git repo'
 				rm -rf .git
 				When run script "$BIN" hook uninstall
 				The status should be failure
-				The stderr should include "not a git repository"
+				The stderr should include "[not-git-repo]"
 			End
 		End
 
 		It 'errors with unknown subcommand'
 			When run script "$BIN" hook unknown
 			The status should be failure
-			The stderr should include "unknown"
+			The stderr should include "[hook-action-unknown]"
 		End
 	End
 
@@ -1228,8 +1320,8 @@ EOF
 		It 'fails if explicit config file does not exist'
 			When run script "$BIN" --config-file /nonexistent/config parse
 			The status should be failure
-			The stderr should include "config file not found"
 			The stderr should include "/nonexistent/config"
+			The stderr should include "[config-not-found]"
 		End
 	End
 
@@ -1244,7 +1336,7 @@ EOF
 				command -v gum &>/dev/null && Skip "gum is installed system-wide"
 				When run script "$BIN" create
 				The status should be failure
-				The stderr should include "gum is required"
+				The stderr should include "[gum-not-found]"
 			End
 		End
 
@@ -1898,7 +1990,7 @@ MOCK
 			Data "invalid message"
 			When run script "$BIN"
 			The status should be failure
-			The stderr should include "invalid commit format"
+			The stderr should include "[header-format]"
 		End
 	End
 
@@ -1965,7 +2057,7 @@ EOF
 			Data "feat(unknown): add feature"
 			When run script "$BIN" --defined-scope lint
 			The status should be failure
-			The stderr should include "unknown scope"
+			The stderr should include "[scope-enum]"
 			The stderr should include "api"
 			The stderr should include "ui"
 		End
@@ -1993,7 +2085,7 @@ EOF
 			Data "feat:    "
 			When run script "$BIN" lint
 			The status should be failure
-			The stderr should include "empty"
+			The stderr should include "[description-empty]"
 		End
 
 		It 'handles config keys with hyphens correctly'
diff --git a/scripts/cz/options.sh b/scripts/cz/options.sh
index fd195d9..389d04d 100644
--- a/scripts/cz/options.sh
+++ b/scripts/cz/options.sh
@@ -14,7 +14,7 @@ parser_definition() {
 	flag    DEFINED_SCOPE    -d --{no-}defined-scope    init:@unset -- "Scope must exist in [scopes]"
 	flag    ENFORCE_PATTERNS -e --{no-}enforce-patterns init:@unset validate:'DEFINED_SCOPE=1' -- "Scope must match file patterns (implies -d)"
 	flag    MULTI_SCOPE      -m --{no-}multi-scope      init:@unset -- "Allow multiple scopes like feat(api,db):"
-	flag    BREAKING_FOOTER      --{no-}breaking-footer  init:@unset -- "Require BREAKING CHANGE footer when ! is used"
+	flag    BREAKING_FOOTER  -b  --{no-}breaking-footer  init:@unset -- "Require BREAKING CHANGE footer when ! is used"
 	flag    QUIET            -q --quiet       -- "Suppress warnings and non-essential output"
 	disp    :usage           -h --help
 	disp    VERSION          -V --version