diff --git a/workspace-server/internal/handlers/workspace_dispatchers_test.go b/workspace-server/internal/handlers/workspace_dispatchers_test.go
new file mode 100644
index 00000000..60380afc
--- /dev/null
+++ b/workspace-server/internal/handlers/workspace_dispatchers_test.go
@@ -0,0 +1,164 @@
+package handlers
+
+import (
+	"context"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/models"
+)
+
+// ==================== resolveDeliveryMode ====================
+// Covers workspace_dispatchers.go / registry.go:resolveDeliveryMode
+
+func TestResolveDeliveryMode_PayloadModeWins(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	ctx := context.Background()
+	for _, mode := range []string{models.DeliveryModePush, models.DeliveryModePoll} {
+		got, err := h.resolveDeliveryMode(ctx, "ws-any-id", mode)
+		if err != nil {
+			t.Errorf("resolveDeliveryMode(payloadMode=%q) unexpected error: %v", mode, err)
+		}
+		if got != mode {
+			t.Errorf("resolveDeliveryMode(payloadMode=%q) = %q, want %q", mode, got, mode)
+		}
+	}
+
+	// DB must NOT have been queried when payloadMode is set.
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("DB expectations not met: %v", err)
+	}
+}
+
+func TestResolveDeliveryMode_ExistingDeliveryMode(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	// Workspace row has existing delivery_mode = "poll"
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-poll").
+		WillReturnRows(sqlmock.NewRows([]string{"delivery_mode", "runtime"}).
+			AddRow("poll", "langgraph"))
+
+	ctx := context.Background()
+	got, err := h.resolveDeliveryMode(ctx, "ws-poll", "")
+	if err != nil {
+		t.Errorf("resolveDeliveryMode() unexpected error: %v", err)
+	}
+	if got != models.DeliveryModePoll {
+		t.Errorf("resolveDeliveryMode() = %q, want %q", got, models.DeliveryModePoll)
+	}
+}
+
+func TestResolveDeliveryMode_ExternalRuntime_DefaultsToPoll(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	// Row exists but delivery_mode is NULL; runtime = "external"
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-external").
+		WillReturnRows(sqlmock.NewRows([]string{"delivery_mode", "runtime"}).
+			AddRow(nil, "external"))
+
+	ctx := context.Background()
+	got, err := h.resolveDeliveryMode(ctx, "ws-external", "")
+	if err != nil {
+		t.Errorf("resolveDeliveryMode() unexpected error: %v", err)
+	}
+	if got != models.DeliveryModePoll {
+		t.Errorf("resolveDeliveryMode() = %q, want %q (external runtime)", got, models.DeliveryModePoll)
+	}
+}
+
+func TestResolveDeliveryMode_SelfHosted_DefaultsToPush(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	// Row exists; delivery_mode is NULL; runtime = "langgraph"
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-self-hosted").
+		WillReturnRows(sqlmock.NewRows([]string{"delivery_mode", "runtime"}).
+			AddRow(nil, "langgraph"))
+
+	ctx := context.Background()
+	got, err := h.resolveDeliveryMode(ctx, "ws-self-hosted", "")
+	if err != nil {
+		t.Errorf("resolveDeliveryMode() unexpected error: %v", err)
+	}
+	if got != models.DeliveryModePush {
+		t.Errorf("resolveDeliveryMode() = %q, want %q (self-hosted default)", got, models.DeliveryModePush)
+	}
+}
+
+func TestResolveDeliveryMode_NotFound_DefaultsToPush(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	// Row not found → sql.ErrNoRows → default push
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-nonexistent").
+		WillReturnError(sql.ErrNoRows)
+
+	ctx := context.Background()
+	got, err := h.resolveDeliveryMode(ctx, "ws-nonexistent", "")
+	if err != nil {
+		t.Errorf("resolveDeliveryMode() unexpected error on no-rows: %v", err)
+	}
+	if got != models.DeliveryModePush {
+		t.Errorf("resolveDeliveryMode() = %q, want %q (not-found default)", got, models.DeliveryModePush)
+	}
+}
+
+func TestResolveDeliveryMode_DBError_Propagated(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-error").
+		WillReturnError(context.DeadlineExceeded)
+
+	ctx := context.Background()
+	_, err := h.resolveDeliveryMode(ctx, "ws-error", "")
+	if err == nil {
+		t.Errorf("resolveDeliveryMode() expected error, got nil")
+	}
+}
+
+func TestResolveDeliveryMode_ExistingDeliveryModeEmptyString(t *testing.T) {
+	// When the DB returns an empty (non-NULL) string for delivery_mode,
+	// it falls through to the runtime check (not the existing.Valid path).
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	h := NewRegistryHandler(broadcaster)
+
+	// delivery_mode is explicitly empty string (not NULL), runtime = "langgraph"
+	// → falls through to runtime check → "push" for non-external
+	mock.ExpectQuery("SELECT delivery_mode, runtime FROM workspaces").
+		WithArgs("ws-empty-mode").
+		WillReturnRows(sqlmock.NewRows([]string{"delivery_mode", "runtime"}).
+			AddRow("", "langgraph"))
+
+	ctx := context.Background()
+	got, err := h.resolveDeliveryMode(ctx, "ws-empty-mode", "")
+	if err != nil {
+		t.Errorf("resolveDeliveryMode() unexpected error: %v", err)
+	}
+	if got != models.DeliveryModePush {
+		t.Errorf("resolveDeliveryMode() = %q, want %q", got, models.DeliveryModePush)
+	}
+}
diff --git a/workspace-server/internal/models/workspace_delivery_mode_test.go b/workspace-server/internal/models/workspace_delivery_mode_test.go
new file mode 100644
index 00000000..0b8a2dc4
--- /dev/null
+++ b/workspace-server/internal/models/workspace_delivery_mode_test.go
@@ -0,0 +1,100 @@
+package models
+
+import "testing"
+
+// ==================== IsValidDeliveryMode ====================
+
+func TestIsValidDeliveryMode_Valid(t *testing.T) {
+	for _, mode := range []string{DeliveryModePush, DeliveryModePoll} {
+		if !IsValidDeliveryMode(mode) {
+			t.Errorf("IsValidDeliveryMode(%q) = false, want true", mode)
+		}
+	}
+}
+
+func TestIsValidDeliveryMode_Invalid(t *testing.T) {
+	cases := []struct {
+		val  string
+		want bool
+	}{
+		{"", false},         // empty string is not valid — callers must resolve the default
+		{"pushx", false},   // typo
+		{"pollx", false},    // typo
+		{"PUSH", false},     // case-sensitive
+		{"PUSH ", false},    // trailing space
+		{"push ", false},    // trailing space
+		{"hybrid", false},   // non-existent mode
+		{"poll ", false},    // trailing space
+	}
+	for _, tc := range cases {
+		got := IsValidDeliveryMode(tc.val)
+		if got != tc.want {
+			t.Errorf("IsValidDeliveryMode(%q) = %v, want %v", tc.val, got, tc.want)
+		}
+	}
+}
+
+// ==================== WorkspaceStatus ====================
+
+func TestWorkspaceStatus_String(t *testing.T) {
+	statuses := []WorkspaceStatus{
+		StatusProvisioning,
+		StatusOnline,
+		StatusOffline,
+		StatusDegraded,
+		StatusFailed,
+		StatusRemoved,
+		StatusPaused,
+		StatusHibernated,
+		StatusHibernating,
+		StatusAwaitingAgent,
+	}
+	for _, s := range statuses {
+		if got := s.String(); got != string(s) {
+			t.Errorf("WorkspaceStatus(%q).String() = %q, want %q", s, got, string(s))
+		}
+	}
+}
+
+func TestAllWorkspaceStatuses_Length(t *testing.T) {
+	// The const block has 10 statuses; AllWorkspaceStatuses must match.
+	if got := len(AllWorkspaceStatuses); got != 10 {
+		t.Errorf("len(AllWorkspaceStatuses) = %d, want 10", got)
+	}
+}
+
+func TestAllWorkspaceStatuses_ContainsAllNamed(t *testing.T) {
+	// Verify every named const appears in AllWorkspaceStatuses exactly once.
+	named := []WorkspaceStatus{
+		StatusProvisioning,
+		StatusOnline,
+		StatusOffline,
+		StatusDegraded,
+		StatusFailed,
+		StatusRemoved,
+		StatusPaused,
+		StatusHibernated,
+		StatusHibernating,
+		StatusAwaitingAgent,
+	}
+	set := make(map[WorkspaceStatus]bool, len(AllWorkspaceStatuses))
+	for _, s := range AllWorkspaceStatuses {
+		set[s] = true
+	}
+	for _, s := range named {
+		if !set[s] {
+			t.Errorf("named status %q missing from AllWorkspaceStatuses", s)
+		}
+	}
+	if len(set) != len(named) {
+		t.Errorf("AllWorkspaceStatuses has %d unique entries, want %d", len(set), len(named))
+	}
+}
+
+func TestAllWorkspaceStatuses_NoEmpty(t *testing.T) {
+	for _, s := range AllWorkspaceStatuses {
+		if s == "" {
+			t.Errorf("AllWorkspaceStatuses contains empty string")
+		}
+	}
+}