diff --git a/src/config/legacy-migrate.test.ts b/src/config/legacy-migrate.test.ts
index e9ea4ac37b..63d93c2951 100644
--- a/src/config/legacy-migrate.test.ts
+++ b/src/config/legacy-migrate.test.ts
@@ -64,3 +64,43 @@ describe("legacy migrate audio transcription", () => {
     expect(res.config?.tools?.media?.audio).toBeUndefined();
   });
 });
+
+describe("legacy migrate mention routing", () => {
+  it("moves routing.groupChat.requireMention into channel group defaults", () => {
+    const res = migrateLegacyConfig({
+      routing: {
+        groupChat: {
+          requireMention: true,
+        },
+      },
+    });
+
+    expect(res.changes).toContain(
+      'Moved routing.groupChat.requireMention → channels.telegram.groups."*".requireMention.',
+    );
+    expect(res.changes).toContain(
+      'Moved routing.groupChat.requireMention → channels.imessage.groups."*".requireMention.',
+    );
+    expect(res.config?.channels?.telegram?.groups?.["*"]?.requireMention).toBe(true);
+    expect(res.config?.channels?.imessage?.groups?.["*"]?.requireMention).toBe(true);
+    expect((res.config as { routing?: unknown } | null)?.routing).toBeUndefined();
+  });
+
+  it("moves channels.telegram.requireMention into groups.*.requireMention", () => {
+    const res = migrateLegacyConfig({
+      channels: {
+        telegram: {
+          requireMention: false,
+        },
+      },
+    });
+
+    expect(res.changes).toContain(
+      'Moved telegram.requireMention → channels.telegram.groups."*".requireMention.',
+    );
+    expect(res.config?.channels?.telegram?.groups?.["*"]?.requireMention).toBe(false);
+    expect(
+      (res.config?.channels?.telegram as { requireMention?: unknown } | undefined)?.requireMention,
+    ).toBeUndefined();
+  });
+});
diff --git a/src/config/legacy.migrations.part-1.ts b/src/config/legacy.migrations.part-1.ts
index 3c4d187610..2a988d3afe 100644
--- a/src/config/legacy.migrations.part-1.ts
+++ b/src/config/legacy.migrations.part-1.ts
@@ -39,6 +39,16 @@ function migrateBindings(
   }
 }
 
+function ensureDefaultGroupEntry(section: Record<string, unknown>): {
+  groups: Record<string, unknown>;
+  entry: Record<string, unknown>;
+} {
+  const groups: Record<string, unknown> = isRecord(section.groups) ? section.groups : {};
+  const defaultKey = "*";
+  const entry: Record<string, unknown> = isRecord(groups[defaultKey]) ? groups[defaultKey] : {};
+  return { groups, entry };
+}
+
 export const LEGACY_CONFIG_MIGRATIONS_PART_1: LegacyConfigMigration[] = [
   {
     id: "bindings.match.provider->bindings.match.channel",
@@ -268,15 +278,8 @@ export const LEGACY_CONFIG_MIGRATIONS_PART_1: LegacyConfigMigration[] = [
           channels[key] && typeof channels[key] === "object"
             ? (channels[key] as Record<string, unknown>)
             : {};
-        const groups =
-          section.groups && typeof section.groups === "object"
-            ? (section.groups as Record<string, unknown>)
-            : {};
+        const { groups, entry } = ensureDefaultGroupEntry(section);
         const defaultKey = "*";
-        const entry =
-          groups[defaultKey] && typeof groups[defaultKey] === "object"
-            ? (groups[defaultKey] as Record<string, unknown>)
-            : {};
         if (entry.requireMention === undefined) {
           entry.requireMention = requireMention;
           groups[defaultKey] = entry;
@@ -354,16 +357,8 @@ export const LEGACY_CONFIG_MIGRATIONS_PART_1: LegacyConfigMigration[] = [
         return;
       }
 
-      const groups =
-        (telegram as Record<string, unknown>).groups &&
-        typeof (telegram as Record<string, unknown>).groups === "object"
-          ? ((telegram as Record<string, unknown>).groups as Record<string, unknown>)
-          : {};
+      const { groups, entry } = ensureDefaultGroupEntry(telegram as Record<string, unknown>);
       const defaultKey = "*";
-      const entry =
-        groups[defaultKey] && typeof groups[defaultKey] === "object"
-          ? (groups[defaultKey] as Record<string, unknown>)
-          : {};
 
       if (entry.requireMention === undefined) {
         entry.requireMention = requireMention;