diff --git a/internal/api/handlers/management/api_key_usage_test.go b/internal/api/handlers/management/api_key_usage_test.go
index f2be17d7..70d9b11e 100644
--- a/internal/api/handlers/management/api_key_usage_test.go
+++ b/internal/api/handlers/management/api_key_usage_test.go
@@ -24,7 +24,6 @@ func sumRecentRequestBuckets(buckets []coreauth.RecentRequestBucket) (int64, int
 
 func TestGetAPIKeyUsage_GroupsByProviderAndAPIKey(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	manager := coreauth.NewManager(nil, nil, nil)
 	if _, err := manager.Register(context.Background(), &coreauth.Auth{
diff --git a/internal/api/handlers/management/auth_files_batch_test.go b/internal/api/handlers/management/auth_files_batch_test.go
index ec001ae5..59b631c8 100644
--- a/internal/api/handlers/management/auth_files_batch_test.go
+++ b/internal/api/handlers/management/auth_files_batch_test.go
@@ -18,7 +18,6 @@ import (
 
 func TestUploadAuthFile_BatchMultipart(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	manager := coreauth.NewManager(nil, nil, nil)
@@ -86,7 +85,6 @@ func TestUploadAuthFile_BatchMultipart(t *testing.T) {
 
 func TestUploadAuthFile_BatchMultipart_InvalidJSONDoesNotOverwriteExistingFile(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	manager := coreauth.NewManager(nil, nil, nil)
@@ -152,7 +150,6 @@ func TestUploadAuthFile_BatchMultipart_InvalidJSONDoesNotOverwriteExistingFile(t
 
 func TestDeleteAuthFile_BatchQuery(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	files := []string{"alpha.json", "beta.json"}
diff --git a/internal/api/handlers/management/auth_files_delete_test.go b/internal/api/handlers/management/auth_files_delete_test.go
index b67f1f66..1287ab12 100644
--- a/internal/api/handlers/management/auth_files_delete_test.go
+++ b/internal/api/handlers/management/auth_files_delete_test.go
@@ -17,7 +17,6 @@ import (
 
 func TestDeleteAuthFile_UsesAuthPathFromManager(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	tempDir := t.TempDir()
 	authDir := filepath.Join(tempDir, "auth")
@@ -101,7 +100,6 @@ func TestDeleteAuthFile_UsesAuthPathFromManager(t *testing.T) {
 
 func TestDeleteAuthFile_FallbackToAuthDirPath(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "fallback-user.json"
@@ -130,7 +128,6 @@ func TestDeleteAuthFile_FallbackToAuthDirPath(t *testing.T) {
 
 func TestDeleteAuthFile_RemovesRuntimeAuth(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "runtime-remove-user.json"
diff --git a/internal/api/handlers/management/auth_files_download_test.go b/internal/api/handlers/management/auth_files_download_test.go
index 88024fbb..b4e39fce 100644
--- a/internal/api/handlers/management/auth_files_download_test.go
+++ b/internal/api/handlers/management/auth_files_download_test.go
@@ -14,7 +14,6 @@ import (
 
 func TestDownloadAuthFile_ReturnsFile(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "download-user.json"
@@ -40,7 +39,6 @@ func TestDownloadAuthFile_ReturnsFile(t *testing.T) {
 
 func TestDownloadAuthFile_RejectsPathSeparators(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	h := NewHandlerWithoutConfigFilePath(&config.Config{AuthDir: t.TempDir()}, nil)
 
diff --git a/internal/api/handlers/management/auth_files_download_windows_test.go b/internal/api/handlers/management/auth_files_download_windows_test.go
index 88fc7f11..bc71c087 100644
--- a/internal/api/handlers/management/auth_files_download_windows_test.go
+++ b/internal/api/handlers/management/auth_files_download_windows_test.go
@@ -16,7 +16,6 @@ import (
 
 func TestDownloadAuthFile_PreventsWindowsSlashTraversal(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	tempDir := t.TempDir()
 	authDir := filepath.Join(tempDir, "auth")
diff --git a/internal/api/handlers/management/auth_files_patch_fields_test.go b/internal/api/handlers/management/auth_files_patch_fields_test.go
index 072e487e..e01f1d5c 100644
--- a/internal/api/handlers/management/auth_files_patch_fields_test.go
+++ b/internal/api/handlers/management/auth_files_patch_fields_test.go
@@ -18,7 +18,6 @@ import (
 
 func TestPatchAuthFileFields_MergeHeadersAndDeleteEmptyValues(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	store := &memoryAuthStore{}
 	manager := coreauth.NewManager(store, nil, nil)
@@ -113,7 +112,6 @@ func TestPatchAuthFileFields_MergeHeadersAndDeleteEmptyValues(t *testing.T) {
 
 func TestPatchAuthFileFields_HeadersEmptyMapIsNoop(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	store := &memoryAuthStore{}
 	manager := coreauth.NewManager(store, nil, nil)
@@ -168,7 +166,6 @@ func TestPatchAuthFileFields_HeadersEmptyMapIsNoop(t *testing.T) {
 
 func TestPatchAuthFileFields_WebsocketsFalseIsUpdate(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	store := &memoryAuthStore{}
 	manager := coreauth.NewManager(store, nil, nil)
@@ -217,7 +214,6 @@ func TestPatchAuthFileFields_WebsocketsFalseIsUpdate(t *testing.T) {
 
 func TestPatchAuthFileFields_ArbitraryFieldsPersistToFile(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "generic.json"
diff --git a/internal/api/handlers/management/auth_files_project_id_test.go b/internal/api/handlers/management/auth_files_project_id_test.go
index 0c462934..3bacc9a4 100644
--- a/internal/api/handlers/management/auth_files_project_id_test.go
+++ b/internal/api/handlers/management/auth_files_project_id_test.go
@@ -16,7 +16,6 @@ import (
 
 func TestListAuthFiles_IncludesProjectIDFromManager(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "gemini-user@example.com-project-a.json"
@@ -55,7 +54,6 @@ func TestListAuthFiles_IncludesProjectIDFromManager(t *testing.T) {
 
 func TestListAuthFilesFromDisk_IncludesProjectID(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	filePath := filepath.Join(authDir, "gemini-user@example.com-project-a.json")
@@ -73,7 +71,6 @@ func TestListAuthFilesFromDisk_IncludesProjectID(t *testing.T) {
 
 func TestListAuthFiles_IncludesWebsocketsFromManager(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	fileName := "codex-user@example.com-pro.json"
@@ -111,7 +108,6 @@ func TestListAuthFiles_IncludesWebsocketsFromManager(t *testing.T) {
 
 func TestListAuthFilesFromDisk_IncludesWebsockets(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	authDir := t.TempDir()
 	filePath := filepath.Join(authDir, "codex-user@example.com-pro.json")
diff --git a/internal/api/handlers/management/auth_files_recent_requests_test.go b/internal/api/handlers/management/auth_files_recent_requests_test.go
index 404bf484..f3c5107c 100644
--- a/internal/api/handlers/management/auth_files_recent_requests_test.go
+++ b/internal/api/handlers/management/auth_files_recent_requests_test.go
@@ -14,7 +14,6 @@ import (
 
 func TestListAuthFiles_IncludesRecentRequestsBuckets(t *testing.T) {
 	t.Setenv("MANAGEMENT_PASSWORD", "")
-	gin.SetMode(gin.TestMode)
 
 	manager := coreauth.NewManager(nil, nil, nil)
 	record := &coreauth.Auth{
diff --git a/internal/api/handlers/management/config_lists_delete_keys_test.go b/internal/api/handlers/management/config_lists_delete_keys_test.go
index a548805e..9897c3c7 100644
--- a/internal/api/handlers/management/config_lists_delete_keys_test.go
+++ b/internal/api/handlers/management/config_lists_delete_keys_test.go
@@ -24,7 +24,6 @@ func writeTestConfigFile(t *testing.T) string {
 
 func TestDeleteGeminiKey_RequiresBaseURLWhenAPIKeyDuplicated(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -52,7 +51,6 @@ func TestDeleteGeminiKey_RequiresBaseURLWhenAPIKeyDuplicated(t *testing.T) {
 
 func TestDeleteGeminiKey_DeletesOnlyMatchingBaseURL(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -83,7 +81,6 @@ func TestDeleteGeminiKey_DeletesOnlyMatchingBaseURL(t *testing.T) {
 
 func TestDeleteClaudeKey_DeletesEmptyBaseURLWhenExplicitlyProvided(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -114,7 +111,6 @@ func TestDeleteClaudeKey_DeletesEmptyBaseURLWhenExplicitlyProvided(t *testing.T)
 
 func TestDeleteVertexCompatKey_DeletesOnlyMatchingBaseURL(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -145,7 +141,6 @@ func TestDeleteVertexCompatKey_DeletesOnlyMatchingBaseURL(t *testing.T) {
 
 func TestDeleteCodexKey_RequiresBaseURLWhenAPIKeyDuplicated(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
diff --git a/internal/api/handlers/management/handler_test.go b/internal/api/handlers/management/handler_test.go
index 73c370ed..148ec030 100644
--- a/internal/api/handlers/management/handler_test.go
+++ b/internal/api/handlers/management/handler_test.go
@@ -41,7 +41,6 @@ func TestAuthenticateManagementKey_LocalhostIPBan_BlocksCorrectKeyDuringBan(t *t
 }
 
 func TestMiddlewareSetsSupportPluginHeader(t *testing.T) {
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg:            &config.Config{},
diff --git a/internal/api/handlers/management/logs_test.go b/internal/api/handlers/management/logs_test.go
index 8c3e0ead..c3b045ee 100644
--- a/internal/api/handlers/management/logs_test.go
+++ b/internal/api/handlers/management/logs_test.go
@@ -706,7 +706,6 @@ func performGetLogs(t *testing.T, h *Handler, target string) logsAPIResponse {
 
 func performGetLogsRaw(t *testing.T, h *Handler, target string) (int, string) {
 	t.Helper()
-	gin.SetMode(gin.TestMode)
 	rec := httptest.NewRecorder()
 	c, _ := gin.CreateTestContext(rec)
 	c.Request = httptest.NewRequest(http.MethodGet, target, nil)
diff --git a/internal/api/handlers/management/oauth_callback_test.go b/internal/api/handlers/management/oauth_callback_test.go
index a9ff971f..065f89f0 100644
--- a/internal/api/handlers/management/oauth_callback_test.go
+++ b/internal/api/handlers/management/oauth_callback_test.go
@@ -14,7 +14,6 @@ import (
 )
 
 func TestPostOAuthCallbackCreatesMissingAuthDir(t *testing.T) {
-	gin.SetMode(gin.TestMode)
 
 	authDir := filepath.Join(t.TempDir(), "missing-auth")
 	state := "test-antigravity-state"
diff --git a/internal/api/handlers/management/plugin_store_test.go b/internal/api/handlers/management/plugin_store_test.go
index c6a92b84..c5037e15 100644
--- a/internal/api/handlers/management/plugin_store_test.go
+++ b/internal/api/handlers/management/plugin_store_test.go
@@ -3,7 +3,6 @@ package management
 import (
 	"archive/zip"
 	"bytes"
-	"context"
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
@@ -25,7 +24,6 @@ import (
 
 func TestListPluginStoreMergesInstalledStatus(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := writeManagementPluginFile(t, "sample-provider")
 	h := &Handler{
@@ -84,7 +82,6 @@ func TestListPluginStoreMergesInstalledStatus(t *testing.T) {
 
 func TestListPluginStoreEscapesRegistryStrings(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -150,7 +147,6 @@ func TestListPluginStoreEscapesRegistryStrings(t *testing.T) {
 
 func TestListPluginStoreShowsLatestReleaseVersionAndCaches(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	httpClient := &countingPluginStoreHTTPClient{responses: fakePluginStoreHTTPClient{
 		"https://registry.example/registry.json": registryJSON(t),
@@ -203,7 +199,6 @@ func TestListPluginStoreShowsLatestReleaseVersionAndCaches(t *testing.T) {
 
 func TestListPluginStoreFallsBackToRegistryVersion(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -242,7 +237,6 @@ func TestListPluginStoreFallsBackToRegistryVersion(t *testing.T) {
 
 func TestListPluginStoreIncludesThirdPartySources(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -304,7 +298,6 @@ func TestListPluginStoreIncludesThirdPartySources(t *testing.T) {
 
 func TestInstallPluginFromStoreWritesFileAndEnablesConfig(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := t.TempDir()
 	archiveData := makeManagementPluginStoreZip(t, "sample-provider"+managementPluginExtension(runtime.GOOS), "library-data")
@@ -335,6 +328,7 @@ func TestInstallPluginFromStoreWritesFileAndEnablesConfig(t *testing.T) {
 			"https://downloads.example/checksums.txt":  []byte(hex.EncodeToString(checksum[:]) + "  " + archiveName + "\n"),
 		},
 	}
+	reloads, reloadDone := captureConfigReload(h)
 
 	rec := httptest.NewRecorder()
 	c, _ := gin.CreateTestContext(rec)
@@ -346,6 +340,11 @@ func TestInstallPluginFromStoreWritesFileAndEnablesConfig(t *testing.T) {
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
 	}
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+	waitForReloadDone(t, reloadDone)
+	if cfgSnapshot == h.cfg {
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
+	}
 	var body pluginInstallResponse
 	if errDecode := json.Unmarshal(rec.Body.Bytes(), &body); errDecode != nil {
 		t.Fatalf("Unmarshal() error = %v; body=%s", errDecode, rec.Body.String())
@@ -371,18 +370,27 @@ func TestInstallPluginFromStoreWritesFileAndEnablesConfig(t *testing.T) {
 	if item.Enabled == nil || !*item.Enabled {
 		t.Fatalf("plugin enabled = %#v, want true", item.Enabled)
 	}
+	snapshotItem := cfgSnapshot.Plugins.Configs["sample-provider"]
+	if snapshotItem.Enabled == nil || !*snapshotItem.Enabled {
+		t.Fatalf("snapshot plugin enabled = %#v, want true", snapshotItem.Enabled)
+	}
 	if h.cfg.Plugins.Enabled {
 		t.Fatal("global plugins.enabled changed to true")
 	}
+	if cfgSnapshot.Plugins.Enabled {
+		t.Fatal("snapshot global plugins.enabled changed to true")
+	}
 	raw := marshalPluginRaw(t, item)
 	if !strings.Contains(raw, "mode: fast") {
 		t.Fatalf("plugin raw config lost custom field:\n%s", raw)
 	}
+	if raw := marshalPluginRaw(t, snapshotItem); !strings.Contains(raw, "mode: fast") {
+		t.Fatalf("snapshot plugin raw config lost custom field:\n%s", raw)
+	}
 }
 
 func TestInstallPluginFromStoreUsesRequestedThirdPartySource(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := t.TempDir()
 	archiveData := makeManagementPluginStoreZip(t, "sample-provider"+managementPluginExtension(runtime.GOOS), "third-party-library-data")
@@ -411,6 +419,7 @@ func TestInstallPluginFromStoreUsesRequestedThirdPartySource(t *testing.T) {
 			"https://downloads.example/checksums.txt":  []byte(hex.EncodeToString(checksum[:]) + "  " + archiveName + "\n"),
 		},
 	}
+	reloads, reloadDone := captureConfigReload(h)
 
 	rec := httptest.NewRecorder()
 	c, _ := gin.CreateTestContext(rec)
@@ -423,6 +432,11 @@ func TestInstallPluginFromStoreUsesRequestedThirdPartySource(t *testing.T) {
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
 	}
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+	waitForReloadDone(t, reloadDone)
+	if cfgSnapshot == h.cfg {
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
+	}
 	var body pluginInstallResponse
 	if errDecode := json.Unmarshal(rec.Body.Bytes(), &body); errDecode != nil {
 		t.Fatalf("Unmarshal() error = %v; body=%s", errDecode, rec.Body.String())
@@ -438,11 +452,14 @@ func TestInstallPluginFromStoreUsesRequestedThirdPartySource(t *testing.T) {
 	if string(data) != "third-party-library-data" {
 		t.Fatalf("installed file = %q, want third-party-library-data", data)
 	}
+	snapshotItem := cfgSnapshot.Plugins.Configs["sample-provider"]
+	if snapshotItem.Enabled == nil || !*snapshotItem.Enabled {
+		t.Fatalf("snapshot plugin enabled = %#v, want true", snapshotItem.Enabled)
+	}
 }
 
 func TestInstallPluginFromStoreRequiresSourceForDuplicateIDs(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -476,7 +493,6 @@ func TestInstallPluginFromStoreRequiresSourceForDuplicateIDs(t *testing.T) {
 
 func TestInstallPluginFromStoreOverwritesFilePreservesConfigAndReloads(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := t.TempDir()
 	existingPath := filepath.Join(pluginsDir, "sample-provider"+managementPluginExtension(runtime.GOOS))
@@ -511,10 +527,7 @@ func TestInstallPluginFromStoreOverwritesFilePreservesConfigAndReloads(t *testin
 			"https://downloads.example/checksums.txt":  []byte(hex.EncodeToString(checksum[:]) + "  " + archiveName + "\n"),
 		},
 	}
-	reloads := make(chan *config.Config, 1)
-	h.SetConfigReloadHook(func(_ context.Context, cfg *config.Config) {
-		reloads <- cfg
-	})
+	reloads, reloadDone := captureConfigReload(h)
 
 	rec := httptest.NewRecorder()
 	c, _ := gin.CreateTestContext(rec)
@@ -526,8 +539,10 @@ func TestInstallPluginFromStoreOverwritesFilePreservesConfigAndReloads(t *testin
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
 	}
-	if cfg := waitForAsyncReload(t, reloads); cfg != h.cfg {
-		t.Fatalf("reload config = %p, want handler config %p", cfg, h.cfg)
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+	waitForReloadDone(t, reloadDone)
+	if cfgSnapshot == h.cfg {
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
 	}
 	data, errRead := os.ReadFile(existingPath)
 	if errRead != nil {
@@ -540,13 +555,23 @@ func TestInstallPluginFromStoreOverwritesFilePreservesConfigAndReloads(t *testin
 	if item.Enabled == nil || !*item.Enabled {
 		t.Fatalf("plugin enabled = %#v, want true", item.Enabled)
 	}
+	snapshotItem := cfgSnapshot.Plugins.Configs["sample-provider"]
+	if snapshotItem.Enabled == nil || !*snapshotItem.Enabled {
+		t.Fatalf("snapshot plugin enabled = %#v, want true", snapshotItem.Enabled)
+	}
 	if item.Priority != 5 {
 		t.Fatalf("plugin priority = %d, want 5", item.Priority)
 	}
+	if snapshotItem.Priority != 5 {
+		t.Fatalf("snapshot plugin priority = %d, want 5", snapshotItem.Priority)
+	}
 	raw := marshalPluginRaw(t, item)
 	if !strings.Contains(raw, "mode: fast") || !strings.Contains(raw, "extra: keep") {
 		t.Fatalf("plugin raw config lost custom fields:\n%s", raw)
 	}
+	if raw := marshalPluginRaw(t, snapshotItem); !strings.Contains(raw, "mode: fast") || !strings.Contains(raw, "extra: keep") {
+		t.Fatalf("snapshot plugin raw config lost custom fields:\n%s", raw)
+	}
 }
 
 func TestEnablePluginConfigLockedPreservesExistingFields(t *testing.T) {
diff --git a/internal/api/handlers/management/plugins_test.go b/internal/api/handlers/management/plugins_test.go
index dfb273c7..a03b217d 100644
--- a/internal/api/handlers/management/plugins_test.go
+++ b/internal/api/handlers/management/plugins_test.go
@@ -32,9 +32,27 @@ func waitForAsyncReload(t *testing.T, reloads <-chan *config.Config) *config.Con
 	}
 }
 
+func waitForReloadDone(t *testing.T, done <-chan struct{}) {
+	t.Helper()
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting for config reload hook to finish")
+	}
+}
+
+func captureConfigReload(h *Handler) (<-chan *config.Config, <-chan struct{}) {
+	reloads := make(chan *config.Config, 1)
+	done := make(chan struct{})
+	h.SetConfigReloadHook(func(_ context.Context, cfg *config.Config) {
+		defer close(done)
+		reloads <- cfg
+	})
+	return reloads, done
+}
+
 func TestListPluginsIncludesScannedAndConfiguredPlugins(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := writeManagementPluginFile(t, "scanned")
 	disabled := false
@@ -117,7 +135,6 @@ func TestListPluginsIncludesScannedAndConfiguredPlugins(t *testing.T) {
 
 func TestGetPluginConfigReturnsPreservedRawConfig(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -174,7 +191,6 @@ options:
 
 func TestGetPluginConfigReturnsEmptyObjectForKnownUnconfiguredPlugin(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := writeManagementPluginFile(t, "scanned")
 	h := &Handler{
@@ -207,7 +223,6 @@ func TestGetPluginConfigReturnsEmptyObjectForKnownUnconfiguredPlugin(t *testing.
 
 func TestGetPluginConfigReturnsNotFoundForUnknownPlugin(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg:            &config.Config{},
@@ -228,7 +243,6 @@ func TestGetPluginConfigReturnsNotFoundForUnknownPlugin(t *testing.T) {
 
 func TestPatchPluginEnabledUpdatesOnlyPluginConfig(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -241,10 +255,7 @@ func TestPatchPluginEnabledUpdatesOnlyPluginConfig(t *testing.T) {
 		},
 		configFilePath: writeTestConfigFile(t),
 	}
-	reloads := make(chan *config.Config, 1)
-	h.SetConfigReloadHook(func(_ context.Context, cfg *config.Config) {
-		reloads <- cfg
-	})
+	reloads, reloadDone := captureConfigReload(h)
 
 	rec := httptest.NewRecorder()
 	c, _ := gin.CreateTestContext(rec)
@@ -257,8 +268,20 @@ func TestPatchPluginEnabledUpdatesOnlyPluginConfig(t *testing.T) {
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
 	}
-	if cfg := waitForAsyncReload(t, reloads); cfg != h.cfg {
-		t.Fatalf("reload config = %p, want handler config %p", cfg, h.cfg)
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+	waitForReloadDone(t, reloadDone)
+	if cfgSnapshot == h.cfg {
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
+	}
+	if cfgSnapshot.Plugins.Enabled {
+		t.Fatal("snapshot global Plugins.Enabled changed to true")
+	}
+	snapshotItem := cfgSnapshot.Plugins.Configs["sample"]
+	if snapshotItem.Enabled == nil || !*snapshotItem.Enabled {
+		t.Fatalf("snapshot sample enabled = %#v, want true", snapshotItem.Enabled)
+	}
+	if raw := marshalPluginRaw(t, snapshotItem); !strings.Contains(raw, "mode: safe") {
+		t.Fatalf("snapshot raw config lost custom field:\n%s", raw)
 	}
 	if h.cfg.Plugins.Enabled {
 		t.Fatal("global Plugins.Enabled changed to true")
@@ -273,9 +296,71 @@ func TestPatchPluginEnabledUpdatesOnlyPluginConfig(t *testing.T) {
 	}
 }
 
+func TestPatchPluginEnabledReloadSnapshotRawImmutability(t *testing.T) {
+	t.Parallel()
+	h := &Handler{
+		cfg: &config.Config{
+			Plugins: config.PluginsConfig{
+				Configs: map[string]config.PluginInstanceConfig{
+					"sample": pluginConfigFromYAML(t, "enabled: false\nmode: first\n"),
+				},
+			},
+		},
+		configFilePath: writeTestConfigFile(t),
+	}
+	reloads := make(chan *config.Config, 1)
+	releaseReload := make(chan struct{})
+	reloadDone := make(chan struct{})
+	h.SetConfigReloadHook(func(_ context.Context, cfg *config.Config) {
+		defer close(reloadDone)
+		reloads <- cfg
+		<-releaseReload
+	})
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Params = gin.Params{{Key: "id", Value: "sample"}}
+	c.Request = httptest.NewRequest(http.MethodPatch, "/v0/management/plugins/sample/enabled", strings.NewReader(`{"enabled":true}`))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	h.PatchPluginEnabled(c)
+
+	if rec.Code != http.StatusOK {
+		close(releaseReload)
+		waitForReloadDone(t, reloadDone)
+		t.Fatalf("status = %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
+	}
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+
+	h.mu.Lock()
+	item := h.cfg.Plugins.Configs["sample"]
+	setPluginRawScalarValue(t, &item.Raw, "mode", "second")
+	h.cfg.Plugins.Configs["sample"] = item
+	h.mu.Unlock()
+
+	if cfgSnapshot == h.cfg {
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
+	}
+	snapshotItem := cfgSnapshot.Plugins.Configs["sample"]
+	if snapshotItem.Enabled == nil || !*snapshotItem.Enabled {
+		t.Fatalf("snapshot sample enabled = %#v, want true", snapshotItem.Enabled)
+	}
+	if got := pluginRawScalarValue(t, snapshotItem, "mode"); got != "first" {
+		t.Fatalf("snapshot raw mode = %q, want first", got)
+	}
+	h.mu.Lock()
+	handlerItem := h.cfg.Plugins.Configs["sample"]
+	h.mu.Unlock()
+	if got := pluginRawScalarValue(t, handlerItem, "mode"); got != "second" {
+		t.Fatalf("handler raw mode = %q, want second", got)
+	}
+
+	close(releaseReload)
+	waitForReloadDone(t, reloadDone)
+}
+
 func TestPutPluginConfigReplacesPluginConfig(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -311,7 +396,6 @@ func TestPutPluginConfigReplacesPluginConfig(t *testing.T) {
 
 func TestPatchPluginConfigMergesAndDeletesFields(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg: &config.Config{
@@ -347,7 +431,6 @@ func TestPatchPluginConfigMergesAndDeletesFields(t *testing.T) {
 
 func TestDeletePluginRemovesDiscoveredFileAndConfig(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	pluginsDir := writeManagementPluginFile(t, "sample")
 	h := &Handler{
@@ -363,8 +446,9 @@ func TestDeletePluginRemovesDiscoveredFileAndConfig(t *testing.T) {
 	}
 	reloads := make(chan *config.Config, 1)
 	releaseReload := make(chan struct{})
-	defer close(releaseReload)
+	reloadDone := make(chan struct{})
 	h.SetConfigReloadHook(func(_ context.Context, cfg *config.Config) {
+		defer close(reloadDone)
 		reloads <- cfg
 		<-releaseReload
 	})
@@ -403,14 +487,23 @@ func TestDeletePluginRemovesDiscoveredFileAndConfig(t *testing.T) {
 	if _, errStat := os.Stat(path); !os.IsNotExist(errStat) {
 		t.Fatalf("plugin file stat error = %v, want not exist", errStat)
 	}
-	if cfg := waitForAsyncReload(t, reloads); cfg != h.cfg {
-		t.Fatalf("reload config = %p, want handler config %p", cfg, h.cfg)
+	cfgSnapshot := waitForAsyncReload(t, reloads)
+	if cfgSnapshot == h.cfg {
+		close(releaseReload)
+		waitForReloadDone(t, reloadDone)
+		t.Fatalf("reload config = handler config %p, want independent snapshot", h.cfg)
 	}
+	if _, ok := cfgSnapshot.Plugins.Configs["sample"]; ok {
+		close(releaseReload)
+		waitForReloadDone(t, reloadDone)
+		t.Fatal("snapshot plugin config still exists after delete")
+	}
+	close(releaseReload)
+	waitForReloadDone(t, reloadDone)
 }
 
 func TestDeletePluginReturnsNotFoundForUnknownPlugin(t *testing.T) {
 	t.Parallel()
-	gin.SetMode(gin.TestMode)
 
 	h := &Handler{
 		cfg:            &config.Config{},
@@ -523,3 +616,25 @@ func marshalPluginRaw(t *testing.T, item config.PluginInstanceConfig) string {
 	}
 	return string(data)
 }
+
+func pluginRawScalarValue(t *testing.T, item config.PluginInstanceConfig, key string) string {
+	t.Helper()
+	for i := 0; i+1 < len(item.Raw.Content); i += 2 {
+		if item.Raw.Content[i] != nil && item.Raw.Content[i].Value == key && item.Raw.Content[i+1] != nil {
+			return item.Raw.Content[i+1].Value
+		}
+	}
+	t.Fatalf("plugin raw missing scalar key %q", key)
+	return ""
+}
+
+func setPluginRawScalarValue(t *testing.T, node *yaml.Node, key, value string) {
+	t.Helper()
+	for i := 0; i+1 < len(node.Content); i += 2 {
+		if node.Content[i] != nil && node.Content[i].Value == key && node.Content[i+1] != nil {
+			node.Content[i+1].Value = value
+			return
+		}
+	}
+	t.Fatalf("plugin raw missing scalar key %q", key)
+}
diff --git a/internal/api/handlers/management/test_main_test.go b/internal/api/handlers/management/test_main_test.go
new file mode 100644
index 00000000..f6ff4e4a
--- /dev/null
+++ b/internal/api/handlers/management/test_main_test.go
@@ -0,0 +1,13 @@
+package management
+
+import (
+	"os"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+)
+
+func TestMain(m *testing.M) {
+	gin.SetMode(gin.TestMode)
+	os.Exit(m.Run())
+}
diff --git a/internal/api/handlers/management/usage_test.go b/internal/api/handlers/management/usage_test.go
index bdb8aa2e..a0777b06 100644
--- a/internal/api/handlers/management/usage_test.go
+++ b/internal/api/handlers/management/usage_test.go
@@ -11,7 +11,6 @@ import (
 )
 
 func TestGetUsageQueuePopsRequestedRecords(t *testing.T) {
-	gin.SetMode(gin.TestMode)
 	withManagementUsageQueue(t, func() {
 		redisqueue.Enqueue([]byte(`{"id":1}`))
 		redisqueue.Enqueue([]byte(`{"id":2}`))
@@ -46,7 +45,6 @@ func TestGetUsageQueuePopsRequestedRecords(t *testing.T) {
 }
 
 func TestGetUsageQueueInvalidCountDoesNotPop(t *testing.T) {
-	gin.SetMode(gin.TestMode)
 	withManagementUsageQueue(t, func() {
 		redisqueue.Enqueue([]byte(`{"id":1}`))