diff --git a/server/service/config/index.ts b/server/service/config/index.ts
index 74a5c65..1673ac0 100644
--- a/server/service/config/index.ts
+++ b/server/service/config/index.ts
@@ -13,6 +13,7 @@ import {
   serializeConfigValue,
   validateConfigValue,
 } from "./registry";
+import { normalizeGlobalConfigValue } from "./normalization";
 
 export class ConfigKeyNotFoundError extends Error {
   code = "CONFIG_KEY_NOT_FOUND";
@@ -108,9 +109,7 @@ export async function setGlobalConfigValue<K extends KnownConfigKey>(key: K, val
   if (scope === "user") {
     throw new ConfigScopeInvalidError(`配置项 ${key} 不支持全局写入`);
   }
-  if (key === "siteName" && typeof value === "string") {
-    value = value.trim();
-  }
+  value = normalizeGlobalConfigValue(key, value);
   if (!validateConfigValue(key, value)) {
     throw new ConfigValueInvalidError(`配置项 ${key} 的值不合法`);
   }
diff --git a/server/service/config/normalization.ts b/server/service/config/normalization.ts
new file mode 100644
index 0000000..61b2337
--- /dev/null
+++ b/server/service/config/normalization.ts
@@ -0,0 +1,18 @@
+import { KnownConfigKey } from "./registry";
+
+const TRIMMABLE_GLOBAL_CONFIG_KEYS = new Set<KnownConfigKey>([
+  "commentMailFromEmail",
+  "commentSmtpHost",
+  "commentSmtpUser",
+  "commentSmtpPass",
+]);
+
+export function normalizeGlobalConfigValue<K extends KnownConfigKey>(key: K, value: unknown): unknown {
+  if (typeof value !== "string") {
+    return value;
+  }
+  if (key === "siteName" || TRIMMABLE_GLOBAL_CONFIG_KEYS.has(key)) {
+    return value.trim();
+  }
+  return value;
+}
diff --git a/server/service/config/registry.test.ts b/server/service/config/registry.test.ts
index 0abe72a..c71c16d 100644
--- a/server/service/config/registry.test.ts
+++ b/server/service/config/registry.test.ts
@@ -1,84 +1,69 @@
 import { describe, expect, test } from "bun:test";
-import { getConfigDefinition, validateConfigValue } from "./registry";
+import { getConfigDefinition, KnownConfigKey, validateConfigValue } from "./registry";
+import { normalizeGlobalConfigValue } from "./normalization";
 
 describe("comment email config validation", () => {
   test("accepts an empty commentMailFromEmail", () => {
-    expect(validateConfigValue("commentMailFromEmail" as never, "")).toBe(true);
+    expect(validateConfigValue("commentMailFromEmail", "")).toBe(true);
   });
 
   test("accepts a valid commentMailFromEmail", () => {
-    expect(validateConfigValue("commentMailFromEmail" as never, "noreply@example.com")).toBe(true);
+    expect(validateConfigValue("commentMailFromEmail", "noreply@example.com")).toBe(true);
   });
 
   test("rejects an invalid commentMailFromEmail", () => {
-    expect(validateConfigValue("commentMailFromEmail" as never, "invalid-email")).toBe(false);
+    expect(validateConfigValue("commentMailFromEmail", "invalid-email")).toBe(false);
   });
 
   test("validates commentNotifyEnabled as boolean", () => {
-    expect(validateConfigValue("commentNotifyEnabled" as never, true)).toBe(true);
-    expect(validateConfigValue("commentNotifyEnabled" as never, false)).toBe(true);
-    expect(validateConfigValue("commentNotifyEnabled" as never, "true")).toBe(false);
+    expect(validateConfigValue("commentNotifyEnabled", true)).toBe(true);
+    expect(validateConfigValue("commentNotifyEnabled", false)).toBe(true);
+    expect(validateConfigValue("commentNotifyEnabled", "true")).toBe(false);
   });
 
   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);
+    expect(validateConfigValue("commentSmtpPort", 1)).toBe(true);
+    expect(validateConfigValue("commentSmtpPort", 65535)).toBe(true);
+    expect(validateConfigValue("commentSmtpPort", 0)).toBe(false);
+    expect(validateConfigValue("commentSmtpPort", 65536)).toBe(false);
+    expect(validateConfigValue("commentSmtpPort", 465)).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,
-    });
+    const expected = [
+      ["commentEmailNotifyEnabled", "global", "boolean", false, false],
+      ["commentMailFromEmail", "global", "string", "", false],
+      ["commentSmtpHost", "global", "string", "", false],
+      ["commentSmtpPort", "global", "number", 465, false],
+      ["commentSmtpSecure", "global", "boolean", true, false],
+      ["commentSmtpUser", "global", "string", "", false],
+      ["commentSmtpPass", "global", "string", "", false],
+    ] as const satisfies readonly [KnownConfigKey, "global", "string" | "number" | "boolean", string | number | boolean, boolean][];
+
+    for (const [key, scope, valueType, defaultValue, userOverridable] of expected) {
+      expect(getConfigDefinition(key)).toMatchObject({
+        scope,
+        valueType,
+        defaultValue,
+        userOverridable,
+      });
+    }
   });
 
   test("keeps metadata consistent for commentNotifyEnabled", () => {
-    expect(getConfigDefinition("commentNotifyEnabled" as never)).toMatchObject({
+    expect(getConfigDefinition("commentNotifyEnabled")).toMatchObject({
       scope: "both",
       valueType: "boolean",
       defaultValue: true,
       userOverridable: true,
     });
   });
+
+  test("normalizes comment email and smtp strings by trimming", () => {
+    expect(normalizeGlobalConfigValue("commentMailFromEmail", "  noreply@example.com  ")).toBe("noreply@example.com");
+    expect(normalizeGlobalConfigValue("commentMailFromEmail", "   ")).toBe("");
+    expect(normalizeGlobalConfigValue("commentSmtpHost", "  smtp.example.com  ")).toBe("smtp.example.com");
+    expect(normalizeGlobalConfigValue("commentSmtpUser", "  username  ")).toBe("username");
+    expect(normalizeGlobalConfigValue("commentSmtpPass", "  password  ")).toBe("password");
+  });
 });