diff --git a/Backend/cmd/posix/main.go b/Backend/cmd/posix/main.go
new file mode 100644
index 0000000..ee83746
--- /dev/null
+++ b/Backend/cmd/posix/main.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+
+	"moku-backend/internal/config"
+	"moku-backend/internal/database"
+	"moku-backend/internal/posixproj"
+)
+
+func main() {
+	command := "rebuild"
+	if len(os.Args) > 1 {
+		command = os.Args[1]
+	}
+
+	switch command {
+	case "rebuild":
+		if err := rebuildProjection(context.Background()); err != nil {
+			log.Fatalf("rebuild POSIX projection: %v", err)
+		}
+	default:
+		log.Fatalf("unsupported posix command %q (supported: rebuild)", command)
+	}
+}
+
+func rebuildProjection(ctx context.Context) error {
+	cfg := config.Load()
+
+	db, err := database.NewPostgres(cfg.PostgresURL)
+	if err != nil {
+		return fmt.Errorf("connect database: %w", err)
+	}
+	defer db.Close()
+
+	summary, err := posixproj.NewProjector(db, cfg.POSIXRoot).RebuildWithSummary(ctx)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf(
+		"POSIX projection rebuilt from %s\n  total nodes: %d\n  directories: %d\n  files: %d\n",
+		cfg.POSIXRoot,
+		summary.TotalNodes,
+		summary.DirectoryCount,
+		summary.FileCount,
+	)
+	return nil
+}
diff --git a/Backend/db/migrations/000004_posix_nodes.sql b/Backend/db/migrations/000004_posix_nodes.sql
new file mode 100644
index 0000000..8de858d
--- /dev/null
+++ b/Backend/db/migrations/000004_posix_nodes.sql
@@ -0,0 +1,45 @@
+-- +goose Up
+
+CREATE TYPE posix_node_kind AS ENUM ('directory', 'file');
+
+CREATE TABLE IF NOT EXISTS posix_nodes (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  path TEXT NOT NULL UNIQUE,
+  parent_path TEXT,
+  name TEXT NOT NULL,
+  depth INTEGER NOT NULL,
+  node_kind posix_node_kind NOT NULL,
+  logical_type TEXT NOT NULL DEFAULT 'generic',
+  file_role TEXT,
+  resource_id TEXT,
+  resource_name TEXT,
+  resource_slug TEXT,
+  installation_id TEXT,
+  organization_id TEXT,
+  organization_slug TEXT,
+  department_slug TEXT,
+  team_slug TEXT,
+  project_slug TEXT,
+  personal_slug TEXT,
+  content_json JSONB,
+  size_bytes BIGINT NOT NULL DEFAULT 0,
+  checksum TEXT,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_posix_nodes_parent_path ON posix_nodes (parent_path);
+CREATE INDEX IF NOT EXISTS idx_posix_nodes_logical_type ON posix_nodes (logical_type);
+CREATE INDEX IF NOT EXISTS idx_posix_nodes_project_slug ON posix_nodes (project_slug);
+CREATE INDEX IF NOT EXISTS idx_posix_nodes_department_slug ON posix_nodes (department_slug);
+CREATE INDEX IF NOT EXISTS idx_posix_nodes_team_slug ON posix_nodes (team_slug);
+
+-- +goose Down
+
+DROP INDEX IF EXISTS idx_posix_nodes_team_slug;
+DROP INDEX IF EXISTS idx_posix_nodes_department_slug;
+DROP INDEX IF EXISTS idx_posix_nodes_project_slug;
+DROP INDEX IF EXISTS idx_posix_nodes_logical_type;
+DROP INDEX IF EXISTS idx_posix_nodes_parent_path;
+DROP TABLE IF EXISTS posix_nodes;
+DROP TYPE IF EXISTS posix_node_kind;
diff --git a/Backend/internal/bootstrap/service.go b/Backend/internal/bootstrap/service.go
index 602c3b8..f56bda1 100644
--- a/Backend/internal/bootstrap/service.go
+++ b/Backend/internal/bootstrap/service.go
@@ -14,6 +14,7 @@ import (
 	"github.com/jackc/pgx/v5"
 
 	"moku-backend/internal/database"
+	"moku-backend/internal/posixproj"
 )
 
 const (
@@ -413,6 +414,10 @@ func (service *Service) SaveStructure(ctx context.Context, input SaveStructureIn
 		return StructureRecord{}, err
 	}
 
+	if err := posixproj.NewProjector(service.db, service.posixRoot).Rebuild(ctx); err != nil {
+		return StructureRecord{}, fmt.Errorf("rebuild POSIX projection: %w", err)
+	}
+
 	return StructureRecord{
 		Installation: installation,
 		Organization: organization,
diff --git a/Backend/internal/posixproj/projector.go b/Backend/internal/posixproj/projector.go
new file mode 100644
index 0000000..76b955a
--- /dev/null
+++ b/Backend/internal/posixproj/projector.go
@@ -0,0 +1,531 @@
+package posixproj
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"moku-backend/internal/database"
+)
+
+const rootProjectionPath = "/"
+
+type Projector struct {
+	db   *database.DB
+	root string
+}
+
+type RebuildSummary struct {
+	TotalNodes      int
+	DirectoryCount  int
+	FileCount       int
+}
+
+type NodeKind string
+
+const (
+	NodeKindDirectory NodeKind = "directory"
+	NodeKindFile      NodeKind = "file"
+)
+
+type Scope struct {
+	InstallationID  string
+	OrganizationID  string
+	OrganizationSlug string
+	DepartmentSlug  string
+	TeamSlug        string
+	ProjectSlug     string
+	PersonalSlug    string
+}
+
+type Node struct {
+	Path            string
+	ParentPath      *string
+	Name            string
+	Depth           int
+	NodeKind        NodeKind
+	LogicalType     string
+	FileRole        string
+	ResourceID      string
+	ResourceName    string
+	ResourceSlug    string
+	InstallationID  string
+	OrganizationID  string
+	OrganizationSlug string
+	DepartmentSlug  string
+	TeamSlug        string
+	ProjectSlug     string
+	PersonalSlug    string
+	ContentJSON     []byte
+	SizeBytes       int64
+	Checksum        string
+}
+
+func NewProjector(db *database.DB, root string) *Projector {
+	return &Projector{db: db, root: strings.TrimSpace(root)}
+}
+
+func (projector *Projector) Rebuild(ctx context.Context) error {
+	_, err := projector.RebuildWithSummary(ctx)
+	return err
+}
+
+func (projector *Projector) RebuildWithSummary(ctx context.Context) (RebuildSummary, error) {
+	if projector == nil || projector.db == nil || projector.db.Pool == nil {
+		return RebuildSummary{}, nil
+	}
+
+	nodes, err := ScanRoot(projector.root)
+	if err != nil {
+		return RebuildSummary{}, err
+	}
+
+	summary := summarizeNodes(nodes)
+
+	tx, err := projector.db.Pool.Begin(ctx)
+	if err != nil {
+		return RebuildSummary{}, err
+	}
+	defer func() {
+		_ = tx.Rollback(ctx)
+	}()
+
+	if _, err := tx.Exec(ctx, `DELETE FROM posix_nodes;`); err != nil {
+		return RebuildSummary{}, fmt.Errorf("clear posix_nodes: %w", err)
+	}
+
+	for _, node := range nodes {
+		if _, err := tx.Exec(ctx, `
+			INSERT INTO posix_nodes (
+				path,
+				parent_path,
+				name,
+				depth,
+				node_kind,
+				logical_type,
+				file_role,
+				resource_id,
+				resource_name,
+				resource_slug,
+				installation_id,
+				organization_id,
+				organization_slug,
+				department_slug,
+				team_slug,
+				project_slug,
+				personal_slug,
+				content_json,
+				size_bytes,
+				checksum
+			) VALUES (
+				$1, $2, $3, $4, $5::posix_node_kind, $6, $7, $8, $9, $10,
+				$11, $12, $13, $14, $15, $16, $17, $18::jsonb, $19, $20
+			);
+		`,
+			node.Path,
+			node.ParentPath,
+			node.Name,
+			node.Depth,
+			string(node.NodeKind),
+			node.LogicalType,
+			node.FileRole,
+			node.ResourceID,
+			node.ResourceName,
+			node.ResourceSlug,
+			node.InstallationID,
+			node.OrganizationID,
+			node.OrganizationSlug,
+			node.DepartmentSlug,
+			node.TeamSlug,
+			node.ProjectSlug,
+			node.PersonalSlug,
+				node.ContentJSON,
+				node.SizeBytes,
+				node.Checksum,
+		); err != nil {
+			return RebuildSummary{}, fmt.Errorf("insert posix node %s: %w", node.Path, err)
+		}
+	}
+
+	if err := tx.Commit(ctx); err != nil {
+		return RebuildSummary{}, err
+	}
+
+	return summary, nil
+}
+
+func ScanRoot(root string) ([]Node, error) {
+	rootPath := strings.TrimSpace(root)
+	if rootPath == "" {
+		return nil, nil
+	}
+
+	info, err := os.Stat(rootPath)
+	if err != nil {
+		return nil, fmt.Errorf("stat POSIX root: %w", err)
+	}
+	if !info.IsDir() {
+		return nil, fmt.Errorf("POSIX root is not a directory: %s", rootPath)
+	}
+
+	rootScope, err := loadRootScope(rootPath)
+	if err != nil {
+		return nil, err
+	}
+
+	nodes := []Node{{
+		Path:             rootProjectionPath,
+		ParentPath:       nil,
+		Name:             filepath.Base(rootPath),
+		Depth:            0,
+		NodeKind:         NodeKindDirectory,
+		LogicalType:      "tenant_root",
+		InstallationID:   rootScope.InstallationID,
+		OrganizationID:   rootScope.OrganizationID,
+		OrganizationSlug: rootScope.OrganizationSlug,
+	}}
+
+	err = filepath.WalkDir(rootPath, func(path string, entry fs.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		if path == rootPath {
+			return nil
+		}
+
+		relPath, err := filepath.Rel(rootPath, path)
+		if err != nil {
+			return err
+		}
+		relPath = filepath.ToSlash(relPath)
+		if relPath == "." {
+			return nil
+		}
+
+		node, err := buildNode(rootPath, relPath, entry, rootScope)
+		if err != nil {
+			return err
+		}
+
+		nodes = append(nodes, node)
+		return nil
+	})
+	if err != nil {
+		return nil, fmt.Errorf("scan POSIX root: %w", err)
+	}
+
+	return nodes, nil
+}
+
+func loadRootScope(rootPath string) (Scope, error) {
+	settingsPath := filepath.Join(rootPath, "settings.json")
+	content, err := os.ReadFile(settingsPath)
+	if err != nil {
+		if errorsIsNotExist(err) {
+			return Scope{}, nil
+		}
+		return Scope{}, fmt.Errorf("read root settings.json: %w", err)
+	}
+
+	var payload map[string]any
+	if err := json.Unmarshal(content, &payload); err != nil {
+		return Scope{}, fmt.Errorf("decode root settings.json: %w", err)
+	}
+
+	installation, _ := payload["installation"].(map[string]any)
+	organization, _ := payload["organization"].(map[string]any)
+
+	return Scope{
+		InstallationID:  stringValue(installation["id"]),
+		OrganizationID:  stringValue(organization["id"]),
+		OrganizationSlug: stringValue(organization["slug"]),
+	}, nil
+}
+
+func buildNode(rootPath, relPath string, entry fs.DirEntry, rootScope Scope) (Node, error) {
+	scope := deriveScope(relPath, rootScope)
+	parentPath := projectionParentPath(relPath)
+	logicalType, fileRole := classifyPath(relPath, entry.IsDir())
+
+	node := Node{
+		Path:             relPath,
+		ParentPath:       parentPath,
+		Name:             entry.Name(),
+		Depth:            strings.Count(relPath, "/") + 1,
+		NodeKind:         NodeKindDirectory,
+		LogicalType:      logicalType,
+		FileRole:         fileRole,
+		InstallationID:   scope.InstallationID,
+		OrganizationID:   scope.OrganizationID,
+		OrganizationSlug: scope.OrganizationSlug,
+		DepartmentSlug:   scope.DepartmentSlug,
+		TeamSlug:         scope.TeamSlug,
+		ProjectSlug:      scope.ProjectSlug,
+		PersonalSlug:     scope.PersonalSlug,
+	}
+
+	if entry.IsDir() {
+		return node, nil
+	}
+
+	absPath := filepath.Join(rootPath, filepath.FromSlash(relPath))
+	content, err := os.ReadFile(absPath)
+	if err != nil {
+		return Node{}, fmt.Errorf("read POSIX file %s: %w", relPath, err)
+	}
+
+	hash := sha256.Sum256(content)
+	node.NodeKind = NodeKindFile
+	node.SizeBytes = int64(len(content))
+	node.Checksum = hex.EncodeToString(hash[:])
+
+	if strings.EqualFold(filepath.Ext(entry.Name()), ".json") {
+		var payload map[string]any
+		if err := json.Unmarshal(content, &payload); err == nil {
+			jsonContent, err := json.Marshal(payload)
+			if err != nil {
+				return Node{}, fmt.Errorf("remarshal POSIX file %s: %w", relPath, err)
+			}
+			node.ContentJSON = jsonContent
+			node.ResourceID = stringValue(payload["id"])
+			node.ResourceName = stringValue(payload["name"])
+			node.ResourceSlug = stringValue(payload["slug"])
+			if node.ResourceID == "" && fileRole == "settings" && logicalType == "tenant" {
+				installation, _ := payload["installation"].(map[string]any)
+				organization, _ := payload["organization"].(map[string]any)
+				node.ResourceID = stringValue(installation["id"])
+				node.ResourceName = stringValue(installation["name"])
+				node.InstallationID = stringValue(installation["id"])
+				node.OrganizationID = stringValue(organization["id"])
+				node.OrganizationSlug = firstNonEmpty(node.OrganizationSlug, stringValue(organization["slug"]))
+			}
+			if node.ResourceID == "" && fileRole == "users" {
+				node.ResourceName = firstNonEmpty(node.ResourceName, parentEntityName(logicalType, scope))
+			}
+		}
+	}
+
+	if node.ResourceSlug == "" {
+		node.ResourceSlug = inferredResourceSlug(logicalType, scope)
+	}
+
+	return node, nil
+}
+
+func deriveScope(relPath string, rootScope Scope) Scope {
+	scope := rootScope
+	parts := strings.Split(relPath, "/")
+	if len(parts) >= 2 && parts[0] == "departments" && strings.HasPrefix(parts[1], "department-") {
+		scope.DepartmentSlug = strings.TrimPrefix(parts[1], "department-")
+	}
+	if len(parts) >= 4 && parts[0] == "departments" && parts[2] == "teams" && strings.HasPrefix(parts[3], "team-") {
+		scope.DepartmentSlug = strings.TrimPrefix(parts[1], "department-")
+		scope.TeamSlug = strings.TrimPrefix(parts[3], "team-")
+	}
+	if len(parts) >= 2 && parts[0] == "projects" && strings.HasPrefix(parts[1], "project-") {
+		scope.ProjectSlug = strings.TrimPrefix(parts[1], "project-")
+	}
+	if len(parts) >= 3 && parts[0] == "users" && parts[1] == "personals" && strings.HasPrefix(parts[2], "personal-") {
+		scope.PersonalSlug = strings.TrimPrefix(parts[2], "personal-")
+	}
+	return scope
+}
+
+func classifyPath(relPath string, isDir bool) (logicalType, fileRole string) {
+	parts := strings.Split(relPath, "/")
+	name := parts[len(parts)-1]
+	if !isDir {
+		fileRole = strings.TrimSuffix(name, filepath.Ext(name))
+	}
+
+	switch {
+	case relPath == "settings.json":
+		return "tenant", "settings"
+	case relPath == "layout.json":
+		return "tenant", "layout"
+	case len(parts) >= 1 && parts[0] == "catalog":
+		if isDir {
+			if len(parts) == 1 {
+				return "catalog", ""
+			}
+			if len(parts) >= 2 && parts[1] == "packs" {
+				if len(parts) == 2 {
+					return "catalog_packs", ""
+				}
+				if len(parts) == 3 {
+					return "catalog_pack", ""
+				}
+				if len(parts) >= 4 && parts[3] == "entries" {
+					return "catalog_pack_entries", ""
+				}
+				return "catalog_entry", ""
+			}
+			if len(parts) >= 2 && parts[1] == "standalone" {
+				if len(parts) == 2 {
+					return "catalog_standalone", ""
+				}
+				return "catalog_entry", ""
+			}
+		}
+		return "catalog", fileRole
+	case len(parts) >= 2 && parts[0] == "departments" && strings.HasPrefix(parts[1], "department-"):
+		if isDir {
+			if len(parts) == 2 {
+				return "department", ""
+			}
+			if len(parts) == 3 && parts[2] == "teams" {
+				return "department_teams", ""
+			}
+			if len(parts) >= 4 && strings.HasPrefix(parts[3], "team-") {
+				return "team", ""
+			}
+		}
+		if len(parts) >= 4 && strings.HasPrefix(parts[3], "team-") {
+			return "team", fileRole
+		}
+		return "department", fileRole
+	case len(parts) >= 2 && parts[0] == "projects" && strings.HasPrefix(parts[1], "project-"):
+		if isDir {
+			if len(parts) == 2 {
+				return "project", ""
+			}
+			if len(parts) == 3 && parts[2] == "tree" {
+				return "project_tree", ""
+			}
+			if strings.Contains(relPath, "/tree/") || strings.HasSuffix(relPath, "/tree") {
+				if strings.HasPrefix(name, "folder-") {
+					return "folder", ""
+				}
+				if strings.HasPrefix(name, "item-") {
+					return "item", ""
+				}
+			}
+		}
+		if strings.Contains(relPath, "/tree/") {
+			if strings.HasPrefix(parts[len(parts)-2], "item-") {
+				return "item", fileRole
+			}
+			if strings.HasPrefix(parts[len(parts)-2], "folder-") {
+				return "folder", fileRole
+			}
+		}
+		return "project", fileRole
+	case len(parts) >= 1 && parts[0] == "users":
+		if isDir {
+			if len(parts) == 1 {
+				return "users", ""
+			}
+			if len(parts) == 2 && parts[1] == "personals" {
+				return "personals", ""
+			}
+			if len(parts) >= 3 && parts[1] == "personals" && strings.HasPrefix(parts[2], "personal-") {
+				return "personal", ""
+			}
+			if strings.Contains(relPath, "/tree/") || strings.HasSuffix(relPath, "/tree") {
+				if strings.HasPrefix(name, "folder-") {
+					return "folder", ""
+				}
+				if strings.HasPrefix(name, "item-") {
+					return "item", ""
+				}
+			}
+		}
+		if len(parts) >= 3 && parts[1] == "personals" && strings.HasPrefix(parts[2], "personal-") {
+			if strings.Contains(relPath, "/tree/") {
+				if strings.HasPrefix(parts[len(parts)-2], "item-") {
+					return "item", fileRole
+				}
+				if strings.HasPrefix(parts[len(parts)-2], "folder-") {
+					return "folder", fileRole
+				}
+			}
+			return "personal", fileRole
+		}
+		return "users", fileRole
+	default:
+		if isDir {
+			return "directory", ""
+		}
+		return "file", fileRole
+	}
+}
+
+func projectionParentPath(relPath string) *string {
+	if relPath == "" || relPath == rootProjectionPath {
+		return nil
+	}
+	parent := filepath.ToSlash(filepath.Dir(relPath))
+	if parent == "." || parent == "" {
+		root := rootProjectionPath
+		return &root
+	}
+	return &parent
+}
+
+func inferredResourceSlug(logicalType string, scope Scope) string {
+	switch logicalType {
+	case "department":
+		return scope.DepartmentSlug
+	case "team":
+		return scope.TeamSlug
+	case "project":
+		return scope.ProjectSlug
+	case "personal":
+		return scope.PersonalSlug
+	default:
+		return ""
+	}
+}
+
+func parentEntityName(logicalType string, scope Scope) string {
+	switch logicalType {
+	case "department":
+		return scope.DepartmentSlug
+	case "team":
+		return scope.TeamSlug
+	case "project":
+		return scope.ProjectSlug
+	case "personal":
+		return scope.PersonalSlug
+	default:
+		return ""
+	}
+}
+
+func stringValue(value any) string {
+	stringValue, _ := value.(string)
+	return strings.TrimSpace(stringValue)
+}
+
+func firstNonEmpty(values ...string) string {
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed != "" {
+			return trimmed
+		}
+	}
+	return ""
+}
+
+func summarizeNodes(nodes []Node) RebuildSummary {
+	summary := RebuildSummary{TotalNodes: len(nodes)}
+	for _, node := range nodes {
+		switch node.NodeKind {
+		case NodeKindDirectory:
+			summary.DirectoryCount++
+		case NodeKindFile:
+			summary.FileCount++
+		}
+	}
+	return summary
+}
+
+func errorsIsNotExist(err error) bool {
+	return err != nil && os.IsNotExist(err)
+}
diff --git a/Backend/internal/posixproj/projector_test.go b/Backend/internal/posixproj/projector_test.go
new file mode 100644
index 0000000..6fc97a0
--- /dev/null
+++ b/Backend/internal/posixproj/projector_test.go
@@ -0,0 +1,148 @@
+package posixproj
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestScanRootBuildsProjectedNodesFromBootstrapShape(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "POSIX")
+
+	mustMkdirAll(t, filepath.Join(root, "catalog", "packs"))
+	mustMkdirAll(t, filepath.Join(root, "catalog", "standalone"))
+	mustMkdirAll(t, filepath.Join(root, "departments", "department-primary-department", "teams", "team-primary-team"))
+	mustMkdirAll(t, filepath.Join(root, "projects", "project-primary-project", "tree"))
+	mustMkdirAll(t, filepath.Join(root, "users", "personals"))
+
+	mustWriteJSON(t, filepath.Join(root, "settings.json"), map[string]any{
+		"installation": map[string]any{
+			"id":             "installation-1",
+			"name":           "MangoPig",
+			"isBootstrapped": true,
+		},
+		"organization": map[string]any{
+			"id":   "org-1",
+			"name": "Primary Organization",
+			"slug": "primary-organization",
+		},
+	})
+	mustWriteJSON(t, filepath.Join(root, "layout.json"), map[string]any{
+		"type": "tenant-layout",
+		"home": map[string]any{"defaultProjectSlug": "primary-project"},
+	})
+	mustWriteJSON(t, filepath.Join(root, "departments", "department-primary-department", "settings.json"), map[string]any{
+		"id":   "dept-1",
+		"name": "Primary Department",
+		"slug": "primary-department",
+		"type": "department",
+	})
+	mustWriteJSON(t, filepath.Join(root, "departments", "department-primary-department", "users.json"), map[string]any{
+		"users": []map[string]any{{"id": "admin-1"}},
+	})
+	mustWriteJSON(t, filepath.Join(root, "departments", "department-primary-department", "teams", "team-primary-team", "settings.json"), map[string]any{
+		"id":   "team-1",
+		"name": "Primary Team",
+		"slug": "primary-team",
+		"type": "team",
+	})
+	mustWriteJSON(t, filepath.Join(root, "projects", "project-primary-project", "settings.json"), map[string]any{
+		"id":   "project-1",
+		"name": "Primary Project",
+		"slug": "primary-project",
+		"type": "project",
+	})
+	mustWriteJSON(t, filepath.Join(root, "projects", "project-primary-project", "home.json"), map[string]any{
+		"type":    "project-home",
+		"project": "primary-project",
+	})
+	mustWriteJSON(t, filepath.Join(root, "users", "settings.json"), map[string]any{
+		"primaryAdminId": "admin-1",
+	})
+	mustWriteJSON(t, filepath.Join(root, "users", "data.json"), map[string]any{
+		"users": []map[string]any{{"id": "admin-1", "email": "ronald@example.com"}},
+	})
+
+	nodes, err := ScanRoot(root)
+	if err != nil {
+		t.Fatalf("ScanRoot() error = %v", err)
+	}
+
+	index := make(map[string]Node, len(nodes))
+	for _, node := range nodes {
+		index[node.Path] = node
+	}
+
+	rootNode, ok := index[rootProjectionPath]
+	if !ok {
+		t.Fatalf("expected synthetic root node")
+	}
+	if rootNode.LogicalType != "tenant_root" {
+		t.Fatalf("expected root logical type tenant_root, got %q", rootNode.LogicalType)
+	}
+	if rootNode.OrganizationSlug != "primary-organization" {
+		t.Fatalf("expected root organization slug primary-organization, got %q", rootNode.OrganizationSlug)
+	}
+
+	tenantSettings := index["settings.json"]
+	if tenantSettings.LogicalType != "tenant" || tenantSettings.FileRole != "settings" {
+		t.Fatalf("unexpected tenant settings classification: %#v", tenantSettings)
+	}
+	if tenantSettings.InstallationID != "installation-1" {
+		t.Fatalf("expected installation id installation-1, got %q", tenantSettings.InstallationID)
+	}
+
+	deptSettings := index["departments/department-primary-department/settings.json"]
+	if deptSettings.DepartmentSlug != "primary-department" {
+		t.Fatalf("expected department slug primary-department, got %q", deptSettings.DepartmentSlug)
+	}
+	if deptSettings.ResourceID != "dept-1" {
+		t.Fatalf("expected department resource id dept-1, got %q", deptSettings.ResourceID)
+	}
+
+	teamSettings := index["departments/department-primary-department/teams/team-primary-team/settings.json"]
+	if teamSettings.TeamSlug != "primary-team" {
+		t.Fatalf("expected team slug primary-team, got %q", teamSettings.TeamSlug)
+	}
+
+	projectSettings := index["projects/project-primary-project/settings.json"]
+	if projectSettings.ProjectSlug != "primary-project" {
+		t.Fatalf("expected project slug primary-project, got %q", projectSettings.ProjectSlug)
+	}
+	if projectSettings.ResourceName != "Primary Project" {
+		t.Fatalf("expected project resource name Primary Project, got %q", projectSettings.ResourceName)
+	}
+
+	projectTree := index["projects/project-primary-project/tree"]
+	if projectTree.LogicalType != "project_tree" || projectTree.NodeKind != NodeKindDirectory {
+		t.Fatalf("unexpected project tree node: %#v", projectTree)
+	}
+
+	usersData := index["users/data.json"]
+	if usersData.LogicalType != "users" || usersData.FileRole != "data" {
+		t.Fatalf("unexpected users data classification: %#v", usersData)
+	}
+	if usersData.Checksum == "" || usersData.SizeBytes == 0 {
+		t.Fatalf("expected users/data.json checksum and size to be populated: %#v", usersData)
+	}
+}
+
+func mustMkdirAll(t *testing.T, path string) {
+	t.Helper()
+	if err := os.MkdirAll(path, 0o755); err != nil {
+		t.Fatalf("MkdirAll(%q) error = %v", path, err)
+	}
+}
+
+func mustWriteJSON(t *testing.T, path string, payload any) {
+	t.Helper()
+	bytes, err := json.MarshalIndent(payload, "", "  ")
+	if err != nil {
+		t.Fatalf("MarshalIndent(%q) error = %v", path, err)
+	}
+	bytes = append(bytes, '\n')
+	if err := os.WriteFile(path, bytes, 0o644); err != nil {
+		t.Fatalf("WriteFile(%q) error = %v", path, err)
+	}
+}
diff --git a/Commands/Local/Dev/backend.just b/Commands/Local/Dev/backend.just
index 7f74c19..8899786 100644
--- a/Commands/Local/Dev/backend.just
+++ b/Commands/Local/Dev/backend.just
@@ -21,6 +21,10 @@ migrate-rebuild:
 migrate-status:
 	cd '{{backend_dir}}' && go run ./cmd/migrate status
 
+# Rebuild the POSIX-to-DB projection from the current POSIX root.
+posix-rebuild:
+	cd '{{backend_dir}}' && go run ./cmd/posix rebuild
+
 # Format backend Go source files.
 fmt:
 	cd '{{backend_dir}}' && gofmt -w ./cmd ./db ./internal