diff --git a/workspace-server/internal/memory/wiring/wiring.go b/workspace-server/internal/memory/wiring/wiring.go
index 6fdad2ba..12badfdc 100644
--- a/workspace-server/internal/memory/wiring/wiring.go
+++ b/workspace-server/internal/memory/wiring/wiring.go
@@ -43,15 +43,37 @@ type Bundle struct {
 // circuit breaker handles ongoing unavailability; we don't want to
 // block workspace-server boot just because the memory plugin is
 // briefly down.
+//
+// Silent-misconfig guard: if MEMORY_V2_CUTOVER=true is set without
+// MEMORY_PLUGIN_URL, the cutoverActive() check in handlers silently
+// returns false and the legacy SQL path serves every request. The
+// operator sees no errors, no warnings, and assumes the cutover is
+// live. Log a LOUD WARN at boot when the env is half-configured so
+// the misconfig is visible in the boot log, not detectable only by
+// observing that the legacy table is still being written to.
 func Build(db *sql.DB) *Bundle {
-	if os.Getenv("MEMORY_PLUGIN_URL") == "" {
+	cutover := os.Getenv("MEMORY_V2_CUTOVER") == "true"
+	pluginURL := os.Getenv("MEMORY_PLUGIN_URL")
+
+	if pluginURL == "" {
+		if cutover {
+			log.Printf("memory-plugin: ⚠️  MEMORY_V2_CUTOVER=true but MEMORY_PLUGIN_URL is unset — cutover is INACTIVE, legacy SQL path is serving every request. Either unset MEMORY_V2_CUTOVER or point MEMORY_PLUGIN_URL at a reachable plugin server.")
+		}
 		return nil
 	}
 	plugin := mclient.New(mclient.Config{})
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 	if hr, err := plugin.Boot(ctx); err != nil {
-		log.Printf("memory-plugin: /v1/health probe failed (will retry per-request): %v", err)
+		// Log even louder when cutover is on — an unreachable plugin
+		// during cutover means writes that the operator THINKS are
+		// going to v2 will silently fall back to legacy via the
+		// circuit breaker on each request. Make it impossible to miss.
+		if cutover {
+			log.Printf("memory-plugin: ⚠️  MEMORY_V2_CUTOVER=true and MEMORY_PLUGIN_URL=%s but /v1/health probe failed (%v). Cutover writes will fall back to legacy via circuit breaker. Verify the plugin server is reachable.", pluginURL, err)
+		} else {
+			log.Printf("memory-plugin: /v1/health probe failed (will retry per-request): %v", err)
+		}
 	} else {
 		log.Printf("memory-plugin: ok, capabilities=%v", hr.Capabilities)
 	}
diff --git a/workspace-server/internal/memory/wiring/wiring_test.go b/workspace-server/internal/memory/wiring/wiring_test.go
index ee7a6840..d8da1efb 100644
--- a/workspace-server/internal/memory/wiring/wiring_test.go
+++ b/workspace-server/internal/memory/wiring/wiring_test.go
@@ -1,9 +1,12 @@
 package wiring
 
 import (
+	"bytes"
 	"context"
+	"log"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"sync"
 	"testing"
 
@@ -151,6 +154,84 @@ func TestNamespaceCleanupFn_PluginErrorDoesNotPanic(t *testing.T) {
 	cleanup(context.Background(), "ws-1")
 }
 
+// captureLogs runs fn with log output captured into a buffer, returns the
+// captured text. Restores the prior log destination on exit.
+func captureLogs(t *testing.T, fn func()) string {
+	t.Helper()
+	var buf bytes.Buffer
+	prev := log.Writer()
+	log.SetOutput(&buf)
+	t.Cleanup(func() { log.SetOutput(prev) })
+	fn()
+	return buf.String()
+}
+
+// TestBuild_WarnsWhenCutoverWithoutPluginURL pins the silent-misconfig
+// guard: an operator who flips MEMORY_V2_CUTOVER=true without also
+// pointing MEMORY_PLUGIN_URL at a plugin server has just disabled the
+// cutover with no error visible. Without this WARN, the only signal
+// is "the legacy table is still being written to" — invisible to
+// every operator who doesn't explicitly check.
+func TestBuild_WarnsWhenCutoverWithoutPluginURL(t *testing.T) {
+	t.Setenv("MEMORY_V2_CUTOVER", "true")
+	t.Setenv("MEMORY_PLUGIN_URL", "")
+	out := captureLogs(t, func() {
+		if got := Build(nil); got != nil {
+			t.Errorf("expected nil bundle, got %+v", got)
+		}
+	})
+	if !strings.Contains(out, "MEMORY_V2_CUTOVER=true") || !strings.Contains(out, "MEMORY_PLUGIN_URL is unset") {
+		t.Errorf("expected loud WARN about half-configured cutover; got log:\n%s", out)
+	}
+}
+
+// TestBuild_NoWarnWhenNeitherSet pins the happy default: an operator
+// running without the v2 plugin should not see scary warnings.
+func TestBuild_NoWarnWhenNeitherSet(t *testing.T) {
+	t.Setenv("MEMORY_V2_CUTOVER", "")
+	t.Setenv("MEMORY_PLUGIN_URL", "")
+	out := captureLogs(t, func() { _ = Build(nil) })
+	if strings.Contains(out, "MEMORY_V2_CUTOVER") {
+		t.Errorf("expected no MEMORY_V2_CUTOVER warning when env is unset; got log:\n%s", out)
+	}
+}
+
+// TestBuild_LoudWarnWhenCutoverAndProbeFails pins the second
+// half-config case: cutover is on AND plugin URL is set, but the
+// /v1/health probe fails (server down or wrong URL). Without this
+// loud WARN, the operator sees only the generic "probe failed" line
+// that gets emitted even when cutover is OFF — hiding the fact that
+// real cutover writes will quietly fall back via circuit breaker.
+func TestBuild_LoudWarnWhenCutoverAndProbeFails(t *testing.T) {
+	t.Setenv("MEMORY_V2_CUTOVER", "true")
+	t.Setenv("MEMORY_PLUGIN_URL", "http://127.0.0.1:1") // bogus port
+	db, _, _ := sqlmock.New()
+	defer db.Close()
+	out := captureLogs(t, func() { _ = Build(db) })
+	if !strings.Contains(out, "MEMORY_V2_CUTOVER=true") || !strings.Contains(out, "probe failed") {
+		t.Errorf("expected loud WARN about cutover-with-failing-probe; got log:\n%s", out)
+	}
+}
+
+// TestBuild_QuietProbeFailWhenCutoverOff: the operator is in PRE-cutover
+// mode (plugin URL set, cutover off — they're warming up the plugin).
+// A failing probe in this state is not a misconfig — it should log the
+// generic message, NOT the loud cutover-specific one (so log noise
+// doesn't drown out real cutover misconfigs in dashboards).
+func TestBuild_QuietProbeFailWhenCutoverOff(t *testing.T) {
+	t.Setenv("MEMORY_V2_CUTOVER", "")
+	t.Setenv("MEMORY_PLUGIN_URL", "http://127.0.0.1:1")
+	db, _, _ := sqlmock.New()
+	defer db.Close()
+	out := captureLogs(t, func() { _ = Build(db) })
+	if strings.Contains(out, "MEMORY_V2_CUTOVER=true") {
+		t.Errorf("expected no cutover-specific warning when cutover is off; got log:\n%s", out)
+	}
+	if !strings.Contains(out, "probe failed") {
+		t.Errorf("expected generic probe-failed log; got log:\n%s", out)
+	}
+}
+
 func pathsAndMethods(paths, methods []string) []string {
 	out := make([]string, len(paths))
 	for i := range paths {