diff --git a/abi/proto/v1/manifest.proto b/abi/proto/v1/manifest.proto
index 1fd166b..15a564d 100644
--- a/abi/proto/v1/manifest.proto
+++ b/abi/proto/v1/manifest.proto
@@ -222,6 +222,9 @@ message AdminPage {
   string title = 2;
   string icon = 3;
   string route = 4;
+  // Optional host sidebar category ID. Empty or unknown values use the
+  // host's fallback Plugins category.
+  string category = 5;
 }
 
 // AiAction mirrors plugin.AIAction.
diff --git a/abi/v1/manifest.pb.go b/abi/v1/manifest.pb.go
index a870f31..7583f2d 100644
--- a/abi/v1/manifest.pb.go
+++ b/abi/v1/manifest.pb.go
@@ -862,11 +862,14 @@ func (x *PageTemplateMeta) GetSlots() []string {
 
 // AdminPage mirrors plugin.AdminPage.
 type AdminPage struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Key           string                 `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
-	Title         string                 `protobuf:"bytes,2,opt,name=title,proto3" json:"title,omitempty"`
-	Icon          string                 `protobuf:"bytes,3,opt,name=icon,proto3" json:"icon,omitempty"`
-	Route         string                 `protobuf:"bytes,4,opt,name=route,proto3" json:"route,omitempty"`
+	state protoimpl.MessageState `protogen:"open.v1"`
+	Key   string                 `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
+	Title string                 `protobuf:"bytes,2,opt,name=title,proto3" json:"title,omitempty"`
+	Icon  string                 `protobuf:"bytes,3,opt,name=icon,proto3" json:"icon,omitempty"`
+	Route string                 `protobuf:"bytes,4,opt,name=route,proto3" json:"route,omitempty"`
+	// Optional host sidebar category ID. Empty or unknown values use the
+	// host's fallback Plugins category.
+	Category      string `protobuf:"bytes,5,opt,name=category,proto3" json:"category,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
@@ -929,6 +932,13 @@ func (x *AdminPage) GetRoute() string {
 	return ""
 }
 
+func (x *AdminPage) GetCategory() string {
+	if x != nil {
+		return x.Category
+	}
+	return ""
+}
+
 // AiAction mirrors plugin.AIAction.
 type AiAction struct {
 	state           protoimpl.MessageState `protogen:"open.v1"`
@@ -1490,12 +1500,13 @@ const file_v1_manifest_proto_rawDesc = "" +
 	"\x03key\x18\x02 \x01(\tR\x03key\x12\x14\n" +
 	"\x05title\x18\x03 \x01(\tR\x05title\x12 \n" +
 	"\vdescription\x18\x04 \x01(\tR\vdescription\x12\x14\n" +
-	"\x05slots\x18\x05 \x03(\tR\x05slots\"]\n" +
+	"\x05slots\x18\x05 \x03(\tR\x05slots\"y\n" +
 	"\tAdminPage\x12\x10\n" +
 	"\x03key\x18\x01 \x01(\tR\x03key\x12\x14\n" +
 	"\x05title\x18\x02 \x01(\tR\x05title\x12\x12\n" +
 	"\x04icon\x18\x03 \x01(\tR\x04icon\x12\x14\n" +
-	"\x05route\x18\x04 \x01(\tR\x05route\"\xa4\x01\n" +
+	"\x05route\x18\x04 \x01(\tR\x05route\x12\x1a\n" +
+	"\bcategory\x18\x05 \x01(\tR\bcategory\"\xa4\x01\n" +
 	"\bAiAction\x12\x10\n" +
 	"\x03key\x18\x01 \x01(\tR\x03key\x12\x14\n" +
 	"\x05title\x18\x02 \x01(\tR\x05title\x12 \n" +
diff --git a/plugin/types.go b/plugin/types.go
index 69ae990..82992e9 100644
--- a/plugin/types.go
+++ b/plugin/types.go
@@ -30,10 +30,11 @@ type EmailSender interface {
 
 // AdminPage defines a page that a plugin registers in the admin sidebar.
 type AdminPage struct {
-	Key   string
-	Title string
-	Icon  string
-	Route string
+	Key      string
+	Title    string
+	Icon     string
+	Route    string
+	Category string // Optional host sidebar category ID; unknown values fall back to Plugins.
 }
 
 // AIAction declares an AI task registered in the AI Action Matrix.
diff --git a/plugin/wasmguest/describe.go b/plugin/wasmguest/describe.go
index 266fa13..f20cec3 100644
--- a/plugin/wasmguest/describe.go
+++ b/plugin/wasmguest/describe.go
@@ -108,7 +108,7 @@ func (g *guest) buildManifest() *abiv1.PluginManifest {
 	if reg.AdminPages != nil {
 		for _, p := range reg.AdminPages() {
 			m.AdminPages = append(m.AdminPages, &abiv1.AdminPage{
-				Key: p.Key, Title: p.Title, Icon: p.Icon, Route: p.Route,
+				Key: p.Key, Title: p.Title, Icon: p.Icon, Route: p.Route, Category: p.Category,
 			})
 		}
 	}
diff --git a/plugin/wasmguest/dispatch_test.go b/plugin/wasmguest/dispatch_test.go
index a252fae..1e26989 100644
--- a/plugin/wasmguest/dispatch_test.go
+++ b/plugin/wasmguest/dispatch_test.go
@@ -66,7 +66,7 @@ func fixtureRegistration() plugin.PluginRegistration {
 			})
 		},
 		AdminPages: func() []plugin.AdminPage {
-			return []plugin.AdminPage{{Key: "fixture", Title: "Fixture Admin", Icon: "puzzle", Route: "/admin/fixture"}}
+			return []plugin.AdminPage{{Key: "fixture", Title: "Fixture Admin", Icon: "puzzle", Route: "/admin/fixture", Category: "content"}}
 		},
 		AIActions: func() []plugin.AIAction {
 			return []plugin.AIAction{{Key: "fixture.summarize", Title: "Summarize", DefaultProvider: "openai", DefaultModel: "gpt-4o"}}
@@ -168,7 +168,7 @@ func TestDescribeManifest(t *testing.T) {
 		m.GetPageTemplates()[0].GetKey() != "fixture-page" {
 		t.Errorf("page_templates = %v", m.GetPageTemplates())
 	}
-	if len(m.GetAdminPages()) != 1 || m.GetAdminPages()[0].GetRoute() != "/admin/fixture" {
+	if len(m.GetAdminPages()) != 1 || m.GetAdminPages()[0].GetRoute() != "/admin/fixture" || m.GetAdminPages()[0].GetCategory() != "content" {
 		t.Errorf("admin_pages = %v", m.GetAdminPages())
 	}
 	if len(m.GetAiActions()) != 1 || m.GetAiActions()[0].GetKey() != "fixture.summarize" {
diff --git a/plugin/wasmguest/testdata/fixture/registration.go b/plugin/wasmguest/testdata/fixture/registration.go
index 6339c31..faf64f7 100644
--- a/plugin/wasmguest/testdata/fixture/registration.go
+++ b/plugin/wasmguest/testdata/fixture/registration.go
@@ -84,7 +84,7 @@ var Registration = plugin.PluginRegistration{
 	},
 	AdminPages: func() []plugin.AdminPage {
 		return []plugin.AdminPage{{
-			Key: "wasmfixture", Title: "Wasm Fixture", Icon: "flask", Route: "/admin/wasmfixture",
+			Key: "wasmfixture", Title: "Wasm Fixture", Icon: "flask", Route: "/admin/wasmfixture", Category: "content",
 		}}
 	},
 }
diff --git a/plugin/wasmguest/wasmhost_test.go b/plugin/wasmguest/wasmhost_test.go
index a21542b..d9fc11f 100644
--- a/plugin/wasmguest/wasmhost_test.go
+++ b/plugin/wasmguest/wasmhost_test.go
@@ -151,7 +151,7 @@ func TestWasmFixtureDescribeRoundTrip(t *testing.T) {
 	if len(m.GetTemplateKeys()) != 1 || m.GetTemplateKeys()[0] != "wasmfixture-page" {
 		t.Errorf("template_keys = %v", m.GetTemplateKeys())
 	}
-	if len(m.GetAdminPages()) != 1 || m.GetAdminPages()[0].GetRoute() != "/admin/wasmfixture" {
+	if len(m.GetAdminPages()) != 1 || m.GetAdminPages()[0].GetRoute() != "/admin/wasmfixture" || m.GetAdminPages()[0].GetCategory() != "content" {
 		t.Errorf("admin_pages = %v", m.GetAdminPages())
 	}