diff --git a/.gitignore b/.gitignore
index e3439ee7..405bacfb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,6 +20,7 @@ report.html
 local/
 tmp/
 dev.log
+.release-state/
 
 # ai
 .tasks/
diff --git a/release.sh b/release.sh
index c3ef0920..6120260b 100755
--- a/release.sh
+++ b/release.sh
@@ -4,6 +4,17 @@ set -euo pipefail
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "$SCRIPT_DIR"
 
+# Exit codes
+declare -r EXIT_SUCCESS=0
+declare -r EXIT_VALIDATION_ERROR=1
+# shellcheck disable=SC2034 # Reserved for future use
+declare -r EXIT_EXECUTION_ERROR=2
+
+# Constants
+GITHUB_REPO_PATH="TypedDevs/bashunit"
+GITHUB_REPO_URL="https://github.com/${GITHUB_REPO_PATH}"
+RELEASE_FILES=("bashunit" "install.sh" "package.json" "CHANGELOG.md")
+
 # Colors
 RED='\033[0;31m'
 GREEN='\033[0;32m'
@@ -11,12 +22,26 @@ YELLOW='\033[1;33m'
 BLUE='\033[0;34m'
 NC='\033[0m' # No Color
 
+# Mode flags
 DRY_RUN=false
+SANDBOX_MODE=false
+FORCE_MODE=false
+VERBOSE_MODE=false
+JSON_OUTPUT=false
 WITH_GH_RELEASE=false
+
+# State tracking
+RELEASE_STATE_DIR=""
+BACKUP_DIR=""
+SANDBOX_DIR=""
+COMPLETED_STEPS=()
+
+# Version tracking
 VERSION=""
+CURRENT_VERSION=""
 
 function release::show_usage() {
-  cat <<EOF
+  cat >&2 <<EOF
 Usage: ./release.sh <version> [options]
 
 Arguments:
@@ -24,26 +49,38 @@ Arguments:
 
 Options:
   --dry-run         Preview changes without modifying any files
-  --with-gh-release Create the GitHub release (default: print manual instructions)
+  --sandbox         Run in sandbox mode (isolated temp directory)
+  --force           Skip all interactive confirmations (for CI)
+  --verbose         Enable detailed logging
+  --json            Output machine-readable JSON summary
+  --with-gh-release Create the GitHub release automatically
+  --rollback        Restore files from most recent backup
   -h, --help        Show this help message
 
-Example:
-  ./release.sh 0.30.0
-  ./release.sh 0.30.0 --dry-run
-  ./release.sh 0.30.0 --with-gh-release
+Exit Codes:
+  0    Success
+  1    Validation error (invalid version, pre-flight check failed)
+  2    Execution error (build failed, git failed)
+
+Examples:
+  ./release.sh 0.31.0                    # Interactive release
+  ./release.sh 0.31.0 --dry-run          # Preview changes
+  ./release.sh 0.31.0 --sandbox          # Test in isolated sandbox
+  ./release.sh 0.31.0 --force --json     # CI mode with JSON output
+  ./release.sh --rollback                # Restore from backup
 EOF
 }
 
 function release::log_info() {
-  echo -e "${BLUE}[INFO]${NC} $1"
+  echo -e "${BLUE}[INFO]${NC} $1" >&2
 }
 
 function release::log_success() {
-  echo -e "${GREEN}[OK]${NC} $1"
+  echo -e "${GREEN}[OK]${NC} $1" >&2
 }
 
 function release::log_warning() {
-  echo -e "${YELLOW}[WARN]${NC} $1"
+  echo -e "${YELLOW}[WARN]${NC} $1" >&2
 }
 
 function release::log_error() {
@@ -51,7 +88,439 @@ function release::log_error() {
 }
 
 function release::log_dry_run() {
-  echo -e "${YELLOW}[DRY-RUN]${NC} $1"
+  echo -e "${YELLOW}[DRY-RUN]${NC} $1" >&2
+}
+
+function release::log_verbose() {
+  if [[ "$VERBOSE_MODE" == true ]]; then
+    echo -e "${BLUE}[VERBOSE]${NC} $1" >&2
+  fi
+}
+
+function release::log_sandbox() {
+  echo -e "${YELLOW}[SANDBOX]${NC} $1" >&2
+}
+
+function release::error_with_suggestion() {
+  local error=$1
+  local suggestion=$2
+  release::log_error "$error"
+  echo -e "  ${YELLOW}Suggestion:${NC} $suggestion" >&2
+}
+
+function release::blank_line() {
+  echo "" >&2
+}
+
+function release::update_file_pattern() {
+  local file=$1
+  local pattern=$2
+  local replacement=$3
+  local description=$4
+
+  if [[ "$DRY_RUN" == true ]]; then
+    release::log_dry_run "Would update $description in $file"
+    return
+  fi
+
+  sed -i.bak "s|$pattern|$replacement|" "$file"
+  rm -f "$file.bak"
+  release::log_success "Updated $description in $file"
+}
+
+#########################
+### PRE-FLIGHT CHECKS ###
+#########################
+
+function release::preflight::check_gh_installed() {
+  release::log_verbose "Checking if gh CLI is installed..."
+  if ! command -v gh >/dev/null 2>&1; then
+    release::error_with_suggestion \
+      "gh CLI is not installed" \
+      "Install from https://cli.github.com/"
+    return 1
+  fi
+  release::log_verbose "gh CLI is installed"
+  return 0
+}
+
+function release::preflight::check_gh_auth() {
+  release::log_verbose "Checking gh authentication..."
+  if ! gh auth status >/dev/null 2>&1; then
+    release::error_with_suggestion \
+      "Not authenticated with GitHub" \
+      "Run 'gh auth login' to authenticate"
+    return 1
+  fi
+  release::log_verbose "gh is authenticated"
+  return 0
+}
+
+function release::preflight::check_git_clean() {
+  release::log_verbose "Checking git working directory..."
+  if [[ -n "$(git status --porcelain 2>/dev/null)" ]]; then
+    release::error_with_suggestion \
+      "Working directory has uncommitted changes" \
+      "Commit or stash changes first: git stash"
+    return 1
+  fi
+  release::log_verbose "Working directory is clean"
+  return 0
+}
+
+function release::preflight::check_branch_main() {
+  release::log_verbose "Checking current branch..."
+  local current_branch
+  current_branch=$(git branch --show-current 2>/dev/null)
+  if [[ "$current_branch" != "main" ]]; then
+    release::error_with_suggestion \
+      "Not on main branch (currently on: $current_branch)" \
+      "Switch to main: git checkout main"
+    return 1
+  fi
+  release::log_verbose "On main branch"
+  return 0
+}
+
+function release::preflight::check_network() {
+  release::log_verbose "Checking network connectivity..."
+  if ! curl --silent --head --fail --max-time 5 https://github.com >/dev/null 2>&1; then
+    release::error_with_suggestion \
+      "Cannot reach github.com" \
+      "Check your network connection"
+    return 1
+  fi
+  release::log_verbose "Network connectivity OK"
+  return 0
+}
+
+function release::preflight::check_required_files() {
+  release::log_verbose "Checking required files..."
+  local required_files=("${RELEASE_FILES[@]}" "build.sh")
+  local missing=()
+
+  for file in "${required_files[@]}"; do
+    if [[ ! -f "$file" ]]; then
+      missing+=("$file")
+    fi
+  done
+
+  if [[ ${#missing[@]} -gt 0 ]]; then
+    release::error_with_suggestion \
+      "Required files missing: ${missing[*]}" \
+      "Ensure you're in the project root directory"
+    return 1
+  fi
+  release::log_verbose "All required files present"
+  return 0
+}
+
+function release::preflight::check_changelog_unreleased() {
+  release::log_verbose "Checking CHANGELOG.md for Unreleased section..."
+  if ! grep -q "^## Unreleased$" CHANGELOG.md 2>/dev/null; then
+    release::error_with_suggestion \
+      "CHANGELOG.md is missing '## Unreleased' section" \
+      "Add '## Unreleased' section at the top of CHANGELOG.md"
+    return 1
+  fi
+
+  # Check if there's content between ## Unreleased and next ## [
+  local unreleased_content
+  unreleased_content=$(awk '/^## Unreleased$/,/^## \[/' CHANGELOG.md | grep -v "^## " | grep -v "^$" | head -1)
+  if [[ -z "$unreleased_content" ]]; then
+    release::error_with_suggestion \
+      "CHANGELOG.md Unreleased section has no content" \
+      "Add release notes under '## Unreleased' section"
+    return 1
+  fi
+  release::log_verbose "CHANGELOG.md has Unreleased section with content"
+  return 0
+}
+
+function release::preflight::check_all() {
+  local checks_passed=true
+  local preflight_checks=(
+    "release::preflight::check_gh_installed"
+    "release::preflight::check_gh_auth"
+    "release::preflight::check_git_clean"
+    "release::preflight::check_branch_main"
+    "release::preflight::check_network"
+    "release::preflight::check_required_files"
+    "release::preflight::check_changelog_unreleased"
+  )
+
+  release::log_info "Running pre-flight checks..."
+
+  for check in "${preflight_checks[@]}"; do
+    if ! "$check"; then
+      checks_passed=false
+    fi
+  done
+
+  if [[ "$checks_passed" == true ]]; then
+    release::log_success "All pre-flight checks passed"
+    return 0
+  else
+    release::log_error "Pre-flight checks failed"
+    return 1
+  fi
+}
+
+#########################
+### BACKUP & ROLLBACK ###
+#########################
+
+function release::backup::init() {
+  RELEASE_STATE_DIR=".release-state"
+  BACKUP_DIR="$RELEASE_STATE_DIR/backup-$(date +%Y%m%d-%H%M%S)"
+  mkdir -p "$BACKUP_DIR"
+  release::log_verbose "Created backup directory: $BACKUP_DIR"
+}
+
+function release::backup::save_file() {
+  local file=$1
+  if [[ -f "$file" ]]; then
+    cp "$file" "$BACKUP_DIR/"
+    release::log_verbose "Backed up: $file"
+  fi
+}
+
+function release::backup::save_all() {
+  release::log_verbose "Backing up files before modification..."
+  for file in "${RELEASE_FILES[@]}"; do
+    release::backup::save_file "$file"
+  done
+  release::log_verbose "All files backed up to $BACKUP_DIR"
+}
+
+function release::state::record_step() {
+  local step=$1
+  COMPLETED_STEPS+=("$step")
+  release::log_verbose "Completed step: $step"
+}
+
+function release::rollback::restore_files() {
+  if [[ -z "$BACKUP_DIR" ]] || [[ ! -d "$BACKUP_DIR" ]]; then
+    release::log_error "No backup directory found"
+    return 1
+  fi
+
+  release::log_info "Restoring files from backup..."
+  for file in "$BACKUP_DIR"/*; do
+    if [[ -f "$file" ]]; then
+      local filename
+      filename=$(basename "$file")
+      cp "$file" "./$filename"
+      release::log_verbose "Restored: $filename"
+    fi
+  done
+  release::log_success "Files restored from backup"
+}
+
+function release::rollback::auto() {
+  release::log_error "Release failed. Initiating rollback..."
+  release::rollback::restore_files || true
+  release::log_info "Rollback complete. Files restored to pre-release state."
+  release::log_info "Manual rollback command if needed: ./release.sh --rollback"
+}
+
+function release::rollback::manual() {
+  # Find most recent backup
+  if [[ ! -d ".release-state" ]]; then
+    release::log_error "No .release-state directory found"
+    exit $EXIT_VALIDATION_ERROR
+  fi
+
+  local latest_backup
+  latest_backup=$(find .release-state -maxdepth 1 -type d -name 'backup-*' 2>/dev/null | sort -r | head -1)
+
+  if [[ -z "$latest_backup" ]]; then
+    release::log_error "No backup found in .release-state"
+    exit $EXIT_VALIDATION_ERROR
+  fi
+
+  release::log_info "Found backup: $latest_backup"
+  BACKUP_DIR="$latest_backup"
+  release::rollback::restore_files
+  release::log_success "Manual rollback complete"
+}
+
+function release::cleanup::state_dir() {
+  if [[ -d "$RELEASE_STATE_DIR" ]]; then
+    rm -rf "$RELEASE_STATE_DIR"
+    release::log_verbose "Cleaned up $RELEASE_STATE_DIR"
+  fi
+}
+
+function release::setup_rollback_trap() {
+  trap 'release::rollback::auto' ERR
+}
+
+function release::clear_rollback_trap() {
+  trap - ERR
+}
+
+#########################
+###   SANDBOX MODE    ###
+#########################
+
+function release::sandbox::create() {
+  SANDBOX_DIR=$(mktemp -d "/tmp/bashunit-release-sandbox-XXXX")
+  release::log_info "Creating sandbox at: $SANDBOX_DIR"
+
+  # Copy repo content excluding .git
+  rsync -a --exclude='.git' --exclude='.release-state' --exclude='node_modules' . "$SANDBOX_DIR/"
+  release::log_verbose "Copied project files to sandbox"
+}
+
+function release::sandbox::setup_git() {
+  cd "$SANDBOX_DIR"
+  git init --quiet
+  git config user.name "Release Sandbox"
+  git config user.email "sandbox@local"
+  git add .
+  git commit --quiet -m "Initial sandbox state"
+  release::log_verbose "Initialized git repository in sandbox"
+}
+
+function release::sandbox::mock_gh() {
+  # Create gh mock function that logs instead of executing
+  gh() {
+    release::log_sandbox "Would execute: gh $*"
+    case "$1" in
+      release)
+        release::log_sandbox "GitHub release would be created"
+        return 0
+        ;;
+      api)
+        # Return empty for contributor lookup
+        echo ""
+        return 0
+        ;;
+      auth)
+        # Auth status check - return success in sandbox
+        return 0
+        ;;
+    esac
+    return 0
+  }
+  export -f gh
+}
+
+function release::sandbox::mock_git_push() {
+  # Override git push to prevent actual pushes
+  local original_git
+  original_git=$(command -v git)
+
+  git() {
+    if [[ "$1" == "push" ]]; then
+      release::log_sandbox "Would execute: git $*"
+      return 0
+    fi
+    "$original_git" "$@"
+  }
+  export -f git
+}
+
+function release::sandbox::show_results() {
+  release::blank_line
+  release::log_info "=== SANDBOX RESULTS ==="
+  release::blank_line
+
+  release::log_info "Files changed:"
+  git diff HEAD~1 --stat 2>/dev/null || true
+  release::blank_line
+
+  release::log_info "Commits made:"
+  git log --oneline HEAD~1..HEAD 2>/dev/null || git log --oneline -1 2>/dev/null
+  release::blank_line
+
+  if [[ -f "/tmp/bashunit-release-notes-${VERSION}.md" ]]; then
+    release::log_info "Release notes preview:"
+    echo "----------------------------------------" >&2
+    cat "/tmp/bashunit-release-notes-${VERSION}.md" >&2
+    echo "----------------------------------------" >&2
+  fi
+}
+
+function release::sandbox::cleanup() {
+  local response
+  release::blank_line
+  echo -en "${YELLOW}Keep sandbox for inspection? [y/N]: ${NC}" >&2
+  read -r response
+
+  if [[ "$response" =~ ^[Yy]$ ]]; then
+    release::log_info "Sandbox preserved at: $SANDBOX_DIR"
+    release::log_info "To clean up later: rm -rf $SANDBOX_DIR"
+  else
+    rm -rf "$SANDBOX_DIR"
+    release::log_success "Sandbox cleaned up"
+  fi
+}
+
+function release::sandbox::run() {
+  release::log_warning "SANDBOX MODE - Running in isolated environment"
+  release::blank_line
+
+  # Limited pre-flight checks for sandbox (only file checks, not git/gh)
+  if ! release::preflight::check_required_files; then
+    exit $EXIT_VALIDATION_ERROR
+  fi
+
+  # Create and setup sandbox
+  release::sandbox::create
+  release::sandbox::setup_git
+  release::sandbox::mock_gh
+  release::sandbox::mock_git_push
+
+  release::log_info "Starting sandbox release simulation..."
+  release::blank_line
+
+  # Run release steps in sandbox (cd already done in setup_git)
+  release::update_bashunit_version "$VERSION"
+  release::update_install_version "$VERSION"
+  release::update_package_json_version "$VERSION"
+  release::update_changelog "$VERSION" "$CURRENT_VERSION"
+
+  release::blank_line
+  release::build_project
+
+  release::blank_line
+  release::update_checksum
+
+  release::blank_line
+  # Commit changes (confirmations skipped in sandbox)
+  release::log_info "Creating release commit..."
+  git add "${RELEASE_FILES[@]}"
+  git commit -m "release: $VERSION" -n
+  release::log_success "Created commit"
+  git tag "$VERSION"
+  release::log_success "Created tag $VERSION"
+
+  # Generate release notes
+  RELEASE_NOTES_FILE="/tmp/bashunit-release-notes-${VERSION}.md"
+  CHECKSUM=$(release::get_checksum)
+  release::generate_release_notes "$VERSION" "$CURRENT_VERSION" "$CHECKSUM" > "$RELEASE_NOTES_FILE"
+  release::log_success "Generated release notes"
+
+  # Show what would happen with push/gh release
+  release::log_sandbox "Would push: git push origin main"
+  release::log_sandbox "Would push tag: git push origin $VERSION"
+  release::log_sandbox "Would create GitHub release with assets: bin/bashunit, bin/checksum"
+  release::log_sandbox "Would update 'latest' branch"
+
+  # Show results
+  release::sandbox::show_results
+
+  release::blank_line
+  echo "========================================" >&2
+  echo -e "${GREEN}Sandbox release simulation complete!${NC}" >&2
+  echo "========================================" >&2
+  release::blank_line
+
+  # Go back to original directory before cleanup prompt
+  cd "$SCRIPT_DIR"
+  release::sandbox::cleanup
 }
 
 function release::validate_semver() {
@@ -59,7 +528,7 @@ function release::validate_semver() {
   if [[ ! "$version" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
     release::log_error "Invalid version format: $version"
     release::log_error "Version must be in semver format (e.g., 0.30.0)"
-    exit 1
+    exit $EXIT_VALIDATION_ERROR
   fi
 }
 
@@ -95,44 +564,29 @@ function release::version_gt() {
 
 function release::update_bashunit_version() {
   local new_version=$1
-  local file="bashunit"
-
-  if [[ "$DRY_RUN" == true ]]; then
-    release::log_dry_run "Would update BASHUNIT_VERSION in $file to $new_version"
-    return
-  fi
-
-  sed -i.bak "s/BASHUNIT_VERSION=\"[^\"]*\"/BASHUNIT_VERSION=\"$new_version\"/" "$file"
-  rm -f "$file.bak"
-  release::log_success "Updated BASHUNIT_VERSION in $file"
+  release::update_file_pattern \
+    "bashunit" \
+    "BASHUNIT_VERSION=\"[^\"]*\"" \
+    "BASHUNIT_VERSION=\"$new_version\"" \
+    "BASHUNIT_VERSION"
 }
 
 function release::update_install_version() {
   local new_version=$1
-  local file="install.sh"
-
-  if [[ "$DRY_RUN" == true ]]; then
-    release::log_dry_run "Would update LATEST_BASHUNIT_VERSION in $file to $new_version"
-    return
-  fi
-
-  sed -i.bak "s/LATEST_BASHUNIT_VERSION=\"[^\"]*\"/LATEST_BASHUNIT_VERSION=\"$new_version\"/" "$file"
-  rm -f "$file.bak"
-  release::log_success "Updated LATEST_BASHUNIT_VERSION in $file"
+  release::update_file_pattern \
+    "install.sh" \
+    "LATEST_BASHUNIT_VERSION=\"[^\"]*\"" \
+    "LATEST_BASHUNIT_VERSION=\"$new_version\"" \
+    "LATEST_BASHUNIT_VERSION"
 }
 
 function release::update_package_json_version() {
   local new_version=$1
-  local file="package.json"
-
-  if [[ "$DRY_RUN" == true ]]; then
-    release::log_dry_run "Would update version in $file to $new_version"
-    return
-  fi
-
-  sed -i.bak "s/\"version\": \"[^\"]*\"/\"version\": \"$new_version\"/" "$file"
-  rm -f "$file.bak"
-  release::log_success "Updated version in $file"
+  release::update_file_pattern \
+    "package.json" \
+    "\"version\": \"[^\"]*\"" \
+    "\"version\": \"$new_version\"" \
+    "version"
 }
 
 function release::update_changelog() {
@@ -141,7 +595,7 @@ function release::update_changelog() {
   local file="CHANGELOG.md"
   local today
   today=$(date +%Y-%m-%d)
-  local compare_url="https://github.com/TypedDevs/bashunit/compare/${current_version}...${new_version}"
+  local compare_url="${GITHUB_REPO_URL}/compare/${current_version}...${new_version}"
 
   if [[ "$DRY_RUN" == true ]]; then
     release::log_dry_run "Would update $file:"
@@ -183,7 +637,7 @@ function release::get_contributors() {
 
   # Get GitHub handles of commit authors since previous version
   # Uses HEAD since the new version tag doesn't exist yet
-  gh api "/repos/TypedDevs/bashunit/compare/${prev_version}...HEAD" \
+  gh api "/repos/${GITHUB_REPO_PATH}/compare/${prev_version}...HEAD" \
     --jq '.commits[].author.login' 2>/dev/null | sort -u | grep -v '^$' || true
 }
 
@@ -216,7 +670,7 @@ function release::generate_release_notes() {
   echo "## Checksum"
   echo "SHA256: \`$checksum\`"
   echo ""
-  local compare_url="https://github.com/TypedDevs/bashunit/compare/$prev_version...$new_version"
+  local compare_url="${GITHUB_REPO_URL}/compare/$prev_version...$new_version"
   echo "**Full Changelog:** [$prev_version...$new_version]($compare_url)"
 }
 
@@ -262,7 +716,7 @@ function release::update_checksum() {
 
   if [[ -z "$checksum" ]]; then
     release::log_error "Could not read checksum from bin/checksum"
-    exit 1
+    exit $EXIT_VALIDATION_ERROR
   fi
 
   if [[ "$DRY_RUN" == true ]]; then
@@ -289,7 +743,13 @@ function release::confirm_action() {
   local prompt=$1
   local response
 
-  echo -en "${YELLOW}$prompt [y/N]: ${NC}"
+  # In force mode, auto-confirm all actions
+  if [[ "$FORCE_MODE" == true ]]; then
+    release::log_info "[FORCE] Auto-confirming: $prompt"
+    return 0
+  fi
+
+  echo -en "${YELLOW}$prompt [y/N]: ${NC}" >&2
   read -r response
 
   if [[ "$response" =~ ^[Yy]$ ]]; then
@@ -299,6 +759,33 @@ function release::confirm_action() {
   fi
 }
 
+#########################
+###    JSON OUTPUT    ###
+#########################
+
+function release::json::summary() {
+  local status=$1
+  local steps_json=""
+
+  # Build steps array
+  if [[ ${#COMPLETED_STEPS[@]} -gt 0 ]]; then
+    steps_json=$(printf '"%s",' "${COMPLETED_STEPS[@]}" | sed 's/,$//')
+  fi
+
+  cat <<EOF
+{
+  "status": "$status",
+  "version": "$VERSION",
+  "current_version": "$CURRENT_VERSION",
+  "sandbox_mode": $SANDBOX_MODE,
+  "dry_run": $DRY_RUN,
+  "force_mode": $FORCE_MODE,
+  "completed_steps": [$steps_json],
+  "timestamp": "$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+}
+EOF
+}
+
 function release::git_commit_and_tag() {
   local new_version=$1
 
@@ -316,7 +803,7 @@ function release::git_commit_and_tag() {
     return
   fi
 
-  git add bashunit install.sh package.json CHANGELOG.md
+  git add "${RELEASE_FILES[@]}"
   git commit -m "release: $new_version" -n
   release::log_success "Created commit"
 
@@ -364,11 +851,11 @@ function release::update_latest_branch() {
 function release::print_release_complete() {
   local new_version=$1
 
-  echo ""
-  echo "========================================"
-  echo -e "${GREEN}Release $new_version complete!${NC}"
-  echo "========================================"
-  echo ""
+  release::blank_line
+  echo "========================================" >&2
+  echo -e "${GREEN}Release $new_version complete!${NC}" >&2
+  echo "========================================" >&2
+  release::blank_line
 }
 
 #########################
@@ -383,13 +870,33 @@ function release::main() {
         DRY_RUN=true
         shift
         ;;
+      --sandbox)
+        SANDBOX_MODE=true
+        shift
+        ;;
+      --force)
+        FORCE_MODE=true
+        shift
+        ;;
+      --verbose)
+        VERBOSE_MODE=true
+        shift
+        ;;
+      --json)
+        JSON_OUTPUT=true
+        shift
+        ;;
       --with-gh-release)
         WITH_GH_RELEASE=true
         shift
         ;;
+      --rollback)
+        release::rollback::manual
+        exit $?
+        ;;
       -h|--help)
         release::show_usage
-        exit 0
+        exit $EXIT_SUCCESS
         ;;
       *)
         if [[ -z "$VERSION" ]]; then
@@ -397,7 +904,7 @@ function release::main() {
         else
           release::log_error "Unknown argument: $1"
           release::show_usage
-          exit 1
+          exit $EXIT_VALIDATION_ERROR
         fi
         shift
         ;;
@@ -408,7 +915,7 @@ function release::main() {
   if [[ -z "$VERSION" ]]; then
     release::log_error "Version argument is required"
     release::show_usage
-    exit 1
+    exit $EXIT_VALIDATION_ERROR
   fi
 
   release::validate_semver "$VERSION"
@@ -420,57 +927,105 @@ function release::main() {
 
   # Validate new version is greater
   if ! release::version_gt "$VERSION" "$CURRENT_VERSION"; then
-    release::log_error "New version ($VERSION) must be greater than current version ($CURRENT_VERSION)"
-    exit 1
+    release::error_with_suggestion \
+      "New version ($VERSION) must be greater than current version ($CURRENT_VERSION)" \
+      "Use a version number higher than $CURRENT_VERSION"
+    exit $EXIT_VALIDATION_ERROR
+  fi
+
+  # Route to appropriate mode
+  if [[ "$SANDBOX_MODE" == true ]]; then
+    release::sandbox::run
+    if [[ "$JSON_OUTPUT" == true ]]; then
+      release::json::summary "success"
+    fi
+    exit $EXIT_SUCCESS
   fi
 
   if [[ "$DRY_RUN" == true ]]; then
-    echo ""
+    release::blank_line
     release::log_warning "DRY-RUN MODE - No files will be modified"
-    echo ""
+    release::blank_line
+  else
+    # Run pre-flight checks for real releases
+    if ! release::preflight::check_all; then
+      if [[ "$JSON_OUTPUT" == true ]]; then
+        release::json::summary "failed"
+      fi
+      exit $EXIT_VALIDATION_ERROR
+    fi
+
+    # Initialize backup/rollback system
+    release::backup::init
+    release::backup::save_all
+    release::setup_rollback_trap
   fi
 
   # Execute release steps
   release::log_info "Starting release process..."
-  echo ""
+  release::blank_line
 
   release::update_bashunit_version "$VERSION"
+  release::state::record_step "update_bashunit_version"
+
   release::update_install_version "$VERSION"
+  release::state::record_step "update_install_version"
+
   release::update_package_json_version "$VERSION"
+  release::state::record_step "update_package_json_version"
+
   release::update_changelog "$VERSION" "$CURRENT_VERSION"
+  release::state::record_step "update_changelog"
 
-  echo ""
+  release::blank_line
   release::build_project
+  release::state::record_step "build_project"
 
-  echo ""
+  release::blank_line
   release::update_checksum
+  release::state::record_step "update_checksum"
 
-  echo ""
+  release::blank_line
   release::git_commit_and_tag "$VERSION"
+  release::state::record_step "git_commit_and_tag"
 
   # Generate formatted release notes
   RELEASE_NOTES_FILE="/tmp/bashunit-release-notes-${VERSION}.md"
   CHECKSUM=$(release::get_checksum)
 
-  echo ""
+  release::blank_line
   if [[ "$DRY_RUN" == true ]]; then
     release::log_dry_run "Would save release notes to $RELEASE_NOTES_FILE"
     release::log_dry_run "Release notes content:"
-    echo "----------------------------------------"
-    release::generate_release_notes "$VERSION" "$CURRENT_VERSION" "$CHECKSUM"
-    echo "----------------------------------------"
+    echo "----------------------------------------" >&2
+    release::generate_release_notes "$VERSION" "$CURRENT_VERSION" "$CHECKSUM" >&2
+    echo "----------------------------------------" >&2
   else
     release::generate_release_notes "$VERSION" "$CURRENT_VERSION" "$CHECKSUM" > "$RELEASE_NOTES_FILE"
     release::log_success "Saved release notes to $RELEASE_NOTES_FILE"
   fi
+  release::state::record_step "generate_release_notes"
 
-  echo ""
+  release::blank_line
   release::create_github_release "$VERSION" "$RELEASE_NOTES_FILE"
+  release::state::record_step "create_github_release"
 
-  echo ""
+  release::blank_line
   release::update_latest_branch "$VERSION"
+  release::state::record_step "update_latest_branch"
+
+  # Cleanup on success
+  if [[ "$DRY_RUN" != true ]]; then
+    release::clear_rollback_trap
+    release::cleanup::state_dir
+  fi
 
   release::print_release_complete "$VERSION"
+
+  # Output JSON summary if requested (to stdout)
+  if [[ "$JSON_OUTPUT" == true ]]; then
+    release::json::summary "success"
+  fi
 }
 
 # Only run main when script is executed directly (not sourced)
diff --git a/tests/unit/fixtures/release/CHANGELOG.md b/tests/unit/fixtures/release/CHANGELOG.md
index c3170ddd..1a251e20 100644
--- a/tests/unit/fixtures/release/CHANGELOG.md
+++ b/tests/unit/fixtures/release/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+### Added
+- Upcoming feature
+
 ## [0.30.0](https://github.com/TypedDevs/bashunit/compare/0.29.0...0.30.0) - 2025-12-14
 
 ### Added
diff --git a/tests/unit/release_test.sh b/tests/unit/release_test.sh
index abfcc214..75f2ff78 100644
--- a/tests/unit/release_test.sh
+++ b/tests/unit/release_test.sh
@@ -277,3 +277,178 @@ function test_generate_release_notes_excludes_older_version_content() {
   # Should NOT include content from older versions (0.29.0)
   assert_not_contains "Previous feature" "$result"
 }
+
+##########################
+# Pre-flight check tests
+##########################
+
+function test_preflight_check_required_files_passes_when_all_exist() {
+  # Run in the project root where all files exist
+  local result
+  result=$(cd "$RELEASE_SCRIPT_DIR" && release::preflight::check_required_files 2>&1)
+  assert_successful_code
+}
+
+function test_preflight_check_required_files_fails_when_file_missing() {
+  local temp_dir
+  temp_dir=$(mktemp -d)
+
+  local result
+  result=$(cd "$temp_dir" && release::preflight::check_required_files 2>&1) || true
+
+  assert_contains "Required files missing" "$result"
+  rm -rf "$temp_dir"
+}
+
+function test_preflight_check_changelog_unreleased_passes_with_content() {
+  local result
+  result=$(cd "$FIXTURES_DIR" && release::preflight::check_changelog_unreleased 2>&1)
+  assert_successful_code
+}
+
+function test_preflight_check_changelog_unreleased_fails_when_missing() {
+  local temp_dir
+  temp_dir=$(mktemp -d)
+  echo "# Changelog" > "$temp_dir/CHANGELOG.md"
+
+  local result
+  result=$(cd "$temp_dir" && release::preflight::check_changelog_unreleased 2>&1) || true
+
+  assert_contains "missing '## Unreleased' section" "$result"
+  rm -rf "$temp_dir"
+}
+
+##########################
+# Backup and rollback tests
+##########################
+
+function test_backup_init_creates_directory() {
+  local temp_dir
+  temp_dir=$(mktemp -d)
+
+  (
+    cd "$temp_dir" || return
+    release::backup::init
+    [[ -d "$BACKUP_DIR" ]] && echo "exists"
+  ) > /tmp/backup_test_result 2>&1
+
+  assert_contains "exists" "$(cat /tmp/backup_test_result)" || true
+  rm -rf "$temp_dir" /tmp/backup_test_result
+  assert_successful_code
+}
+
+function test_backup_save_file_copies_file() {
+  local temp_dir
+  temp_dir=$(mktemp -d)
+
+  local result
+  result=$(
+    cd "$temp_dir" || return
+    echo "test content" > testfile.txt
+    release::backup::init
+    release::backup::save_file "testfile.txt"
+    cat "$BACKUP_DIR/testfile.txt"
+  )
+
+  assert_same "test content" "$result"
+  rm -rf "$temp_dir"
+}
+
+function test_rollback_restore_files_restores_backup() {
+  local temp_dir
+  temp_dir=$(mktemp -d)
+
+  local result
+  result=$(
+    cd "$temp_dir" || return
+    echo "original content" > testfile.txt
+    release::backup::init
+    release::backup::save_file "testfile.txt"
+    echo "modified content" > testfile.txt
+    release::rollback::restore_files 2>/dev/null
+    cat testfile.txt
+  )
+
+  assert_same "original content" "$result"
+  rm -rf "$temp_dir"
+}
+
+##########################
+# Force mode tests
+##########################
+
+function test_confirm_action_auto_confirms_in_force_mode() {
+  FORCE_MODE=true
+  local result
+  result=$(release::confirm_action "Test prompt" 2>&1)
+  local exit_code=$?
+  FORCE_MODE=false
+  assert_same 0 "$exit_code"
+}
+
+##########################
+# JSON output tests
+##########################
+
+function test_json_summary_generates_valid_json() {
+  VERSION="0.31.0"
+  CURRENT_VERSION="0.30.0"
+  SANDBOX_MODE=false
+  DRY_RUN=false
+  FORCE_MODE=false
+  COMPLETED_STEPS=("step1" "step2")
+
+  local result
+  result=$(release::json::summary "success")
+
+  assert_contains '"status": "success"' "$result"
+  assert_contains '"version": "0.31.0"' "$result"
+  assert_contains '"current_version": "0.30.0"' "$result"
+  assert_contains '"completed_steps": ["step1","step2"]' "$result"
+}
+
+function test_json_summary_handles_empty_steps() {
+  # shellcheck disable=SC2034 # Variables used by release::json::summary
+  VERSION="0.31.0"
+  # shellcheck disable=SC2034
+  CURRENT_VERSION="0.30.0"
+  # shellcheck disable=SC2034
+  SANDBOX_MODE=false
+  # shellcheck disable=SC2034
+  DRY_RUN=false
+  # shellcheck disable=SC2034
+  FORCE_MODE=false
+  COMPLETED_STEPS=()
+
+  local result
+  result=$(release::json::summary "success")
+
+  assert_contains '"completed_steps": []' "$result"
+}
+
+##########################
+# State tracking tests
+##########################
+
+function test_state_record_step_adds_to_completed_steps() {
+  COMPLETED_STEPS=()
+  # shellcheck disable=SC2034 # Used by release::state::record_step
+  VERBOSE_MODE=false
+
+  release::state::record_step "test_step"
+
+  assert_same "test_step" "${COMPLETED_STEPS[0]}"
+}
+
+##########################
+# Error with suggestion tests
+##########################
+
+function test_error_with_suggestion_shows_both_messages() {
+  local result
+  result=$(release::error_with_suggestion "Test error" "Test suggestion" 2>&1)
+
+  assert_contains "Test error" "$result"
+  assert_contains "Suggestion:" "$result"
+  assert_contains "Test suggestion" "$result"
+}