diff --git a/server/service/config/registry.test.ts b/server/service/config/registry.test.ts
index 3cbbaec..0abe72a 100644
--- a/server/service/config/registry.test.ts
+++ b/server/service/config/registry.test.ts
@@ -2,6 +2,10 @@ import { describe, expect, test } from "bun:test";
 import { getConfigDefinition, validateConfigValue } from "./registry";
 
 describe("comment email config validation", () => {
+  test("accepts an empty commentMailFromEmail", () => {
+    expect(validateConfigValue("commentMailFromEmail" as never, "")).toBe(true);
+  });
+
   test("accepts a valid commentMailFromEmail", () => {
     expect(validateConfigValue("commentMailFromEmail" as never, "noreply@example.com")).toBe(true);
   });
@@ -17,16 +21,64 @@ describe("comment email config validation", () => {
   });
 
   test("enforces commentSmtpPort boundaries", () => {
+    expect(validateConfigValue("commentSmtpPort" as never, 1)).toBe(true);
+    expect(validateConfigValue("commentSmtpPort" as never, 65535)).toBe(true);
     expect(validateConfigValue("commentSmtpPort" as never, 0)).toBe(false);
     expect(validateConfigValue("commentSmtpPort" as never, 65536)).toBe(false);
     expect(validateConfigValue("commentSmtpPort" as never, 465)).toBe(true);
   });
 
-  test("defines commentNotifyEnabled as user-overridable both-scope key", () => {
-    const definition = getConfigDefinition("commentNotifyEnabled" as never);
-    expect(definition.scope).toBe("both");
-    expect(definition.valueType).toBe("boolean");
-    expect(definition.defaultValue).toBe(true);
-    expect(definition.userOverridable).toBe(true);
+  test("keeps metadata consistent for new global comment config keys", () => {
+    expect(getConfigDefinition("commentEmailNotifyEnabled" as never)).toMatchObject({
+      scope: "global",
+      valueType: "boolean",
+      defaultValue: false,
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentMailFromEmail" as never)).toMatchObject({
+      scope: "global",
+      valueType: "string",
+      defaultValue: "",
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentSmtpHost" as never)).toMatchObject({
+      scope: "global",
+      valueType: "string",
+      defaultValue: "",
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentSmtpPort" as never)).toMatchObject({
+      scope: "global",
+      valueType: "number",
+      defaultValue: 465,
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentSmtpSecure" as never)).toMatchObject({
+      scope: "global",
+      valueType: "boolean",
+      defaultValue: true,
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentSmtpUser" as never)).toMatchObject({
+      scope: "global",
+      valueType: "string",
+      defaultValue: "",
+      userOverridable: false,
+    });
+    expect(getConfigDefinition("commentSmtpPass" as never)).toMatchObject({
+      scope: "global",
+      valueType: "string",
+      defaultValue: "",
+      userOverridable: false,
+    });
+  });
+
+  test("keeps metadata consistent for commentNotifyEnabled", () => {
+    expect(getConfigDefinition("commentNotifyEnabled" as never)).toMatchObject({
+      scope: "both",
+      valueType: "boolean",
+      defaultValue: true,
+      userOverridable: true,
+    });
   });
 });