diff --git a/internal/config/config.go b/internal/config/config.go
index 62a0d3f..6c6b1b6 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -59,6 +59,35 @@ func ResolveProjectRoot() string {
 	return expandPath(v)
 }
 
+// SearchRoots returns the deduplicated list of workspace roots that all query
+// and listing operations must consult. Always includes CTASK_ROOT; also
+// includes CTASK_PROJECT_ROOT when set and different from CTASK_ROOT.
+func SearchRoots() []string {
+	taskRoot := ResolveRoot()
+	roots := []string{taskRoot}
+
+	projRoot := ResolveProjectRoot()
+	if projRoot == "" {
+		return roots
+	}
+
+	if samePath(taskRoot, projRoot) {
+		return roots
+	}
+	return append(roots, projRoot)
+}
+
+// samePath reports whether two absolute paths refer to the same directory
+// on the current platform. Uses case-insensitive compare on Windows.
+func samePath(a, b string) bool {
+	ac := filepath.Clean(a)
+	bc := filepath.Clean(b)
+	if runtime.GOOS == "windows" {
+		return strings.EqualFold(ac, bc)
+	}
+	return ac == bc
+}
+
 // EnvVars returns the environment variables to export into child sessions.
 // taskType must be "task" or "project"; an empty value defaults to "task".
 func EnvVars(slug, mode, root, workspace, category, taskType string) map[string]string {
diff --git a/internal/config/config_roots_test.go b/internal/config/config_roots_test.go
new file mode 100644
index 0000000..179e018
--- /dev/null
+++ b/internal/config/config_roots_test.go
@@ -0,0 +1,53 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestSearchRootsUnsetProjectRoot(t *testing.T) {
+	os.Unsetenv("CTASK_PROJECT_ROOT")
+	os.Setenv("CTASK_ROOT", t.TempDir())
+	defer os.Unsetenv("CTASK_ROOT")
+
+	roots := SearchRoots()
+	if len(roots) != 1 {
+		t.Fatalf("expected 1 root, got %d: %v", len(roots), roots)
+	}
+	if roots[0] != ResolveRoot() {
+		t.Errorf("root mismatch: got %q, want %q", roots[0], ResolveRoot())
+	}
+}
+
+func TestSearchRootsDistinctProjectRoot(t *testing.T) {
+	taskRoot := t.TempDir()
+	projRoot := t.TempDir()
+	os.Setenv("CTASK_ROOT", taskRoot)
+	os.Setenv("CTASK_PROJECT_ROOT", projRoot)
+	defer os.Unsetenv("CTASK_ROOT")
+	defer os.Unsetenv("CTASK_PROJECT_ROOT")
+
+	roots := SearchRoots()
+	if len(roots) != 2 {
+		t.Fatalf("expected 2 roots, got %d: %v", len(roots), roots)
+	}
+	absTask, _ := filepath.Abs(taskRoot)
+	absProj, _ := filepath.Abs(projRoot)
+	if roots[0] != absTask || roots[1] != absProj {
+		t.Errorf("roots: got %v, want [%q, %q]", roots, absTask, absProj)
+	}
+}
+
+func TestSearchRootsSameRootDedupes(t *testing.T) {
+	d := t.TempDir()
+	os.Setenv("CTASK_ROOT", d)
+	os.Setenv("CTASK_PROJECT_ROOT", d)
+	defer os.Unsetenv("CTASK_ROOT")
+	defer os.Unsetenv("CTASK_PROJECT_ROOT")
+
+	roots := SearchRoots()
+	if len(roots) != 1 {
+		t.Fatalf("expected 1 root (dedup), got %d: %v", len(roots), roots)
+	}
+}