diff --git a/docs/inkssg.md b/docs/inkssg.md
index 7aee3de..264a341 100644
--- a/docs/inkssg.md
+++ b/docs/inkssg.md
@@ -197,7 +197,8 @@ Supported fields:
 
 - `name` — site name (available as `.Site.Name` in templates)
 - `default_theme` — theme to use if not set in frontmatter
-- `output_dir` — output directory (defaults to `public/`)
+- `output_dir` — output directory (defaults to `public/`). Must be inside the project root.
+- `pages_dir` — where pages live (defaults to `pages/`)
 
 ## ink.yaml vs frontmatter
 
diff --git a/inkssg.go b/inkssg.go
index a5afaf7..ab748bb 100644
--- a/inkssg.go
+++ b/inkssg.go
@@ -26,11 +26,12 @@ func hasEmbeddedThemes() bool {
 }
 
 type Site struct {
-	Dir    string
-	Pages  []Page
-	Output string
-	Theme  string
-	Config *SiteConfig
+	Dir      string
+	Pages    []Page
+	Output   string
+	Theme    string
+	PagesDir string
+	Config   *SiteConfig
 }
 
 type Page struct {
@@ -51,6 +52,7 @@ type SiteConfig struct {
 	Install      string    `yaml:"install"`
 	DefaultTheme string    `yaml:"default_theme"`
 	OutputDir    string    `yaml:"output_dir"`
+	PagesDir     string    `yaml:"pages_dir"`
 	Links        []Link    `yaml:"links"`
 	Projects     []Project `yaml:"projects"`
 	Meta         Meta      `yaml:"meta"`
@@ -164,11 +166,12 @@ func Build(paths ...string) error {
 
 func NewSite(dir string) (*Site, error) {
 	site := &Site{
-		Dir:    dir,
-		Pages:  []Page{},
-		Output: "public",
-		Theme:  "minimal",
-		Config: &SiteConfig{},
+		Dir:      dir,
+		Pages:    []Page{},
+		Output:   "public",
+		Theme:    "minimal",
+		PagesDir: "pages",
+		Config:   &SiteConfig{},
 	}
 
 	if err := site.loadConfig(); err != nil {
@@ -202,20 +205,24 @@ func (s *Site) loadConfig() error {
 		s.Theme = config.DefaultTheme
 	}
 
+	if config.PagesDir != "" {
+		s.PagesDir = config.PagesDir
+	}
+
 	s.Config = &config
 
 	return nil
 }
 
 func (s *Site) detect() error {
-	pagesDir := filepath.Join(s.Dir, "pages")
+	pagesDir := filepath.Join(s.Dir, s.PagesDir)
 	if _, err := os.Stat(pagesDir); os.IsNotExist(err) {
-		return fmt.Errorf("no pages/ folder found. Run 'inkssg new .' to scaffold a site.")
+		return fmt.Errorf("no %s/ folder found. Run 'inkssg new .' to scaffold a site.", s.PagesDir)
 	}
 
 	entries, err := os.ReadDir(pagesDir)
 	if err != nil {
-		return fmt.Errorf("cannot read pages/: %w", err)
+		return fmt.Errorf("cannot read %s/: %w", s.PagesDir, err)
 	}
 
 	for _, entry := range entries {
@@ -313,9 +320,39 @@ func (p *Page) renderMarkdown(data []byte, contentType string) string {
 	return buf.String()
 }
 
+func (s *Site) validateOutput() error {
+	if strings.TrimSpace(s.Output) == "" {
+		return fmt.Errorf("output_dir cannot be empty")
+	}
+
+	absDir, err := filepath.Abs(s.Dir)
+	if err != nil {
+		return fmt.Errorf("invalid project dir: %w", err)
+	}
+	absOut, err := filepath.Abs(filepath.Join(s.Dir, s.Output))
+	if err != nil {
+		return fmt.Errorf("invalid output_dir: %w", err)
+	}
+
+	if absOut == absDir {
+		return fmt.Errorf("output_dir cannot be the project root (would delete sources on rebuild)")
+	}
+
+	rel, err := filepath.Rel(absDir, absOut)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return fmt.Errorf("output_dir must be inside the project directory, got %q", s.Output)
+	}
+
+	return nil
+}
+
 func (s *Site) Build() error {
 	start := time.Now()
 
+	if err := s.validateOutput(); err != nil {
+		return err
+	}
+
 	if err := os.RemoveAll(filepath.Join(s.Dir, s.Output)); err != nil {
 		return fmt.Errorf("cannot clean output dir: %w", err)
 	}