diff --git a/src/connectors/sources/gmail.ts b/src/connectors/sources/gmail.ts
index 64611b50..e12242b3 100644
--- a/src/connectors/sources/gmail.ts
+++ b/src/connectors/sources/gmail.ts
@@ -25,9 +25,9 @@ type GmailConfig = {
   enabled?: boolean;
   format?: GmailMessageFormat;
   includeSpamTrash?: boolean;
-  labelIds?: string[];
+  labelIds?: unknown;
   maxMessages?: number;
-  metadataHeaders?: string[];
+  metadataHeaders?: unknown;
   pageSize?: number;
   query?: string;
   readOnlyOperations?: unknown[];
@@ -186,7 +186,7 @@ async function listGmailMessages(
   accessToken: string,
   options: {
     includeSpamTrash?: boolean;
-    labelIds?: string[];
+    labelIds?: unknown;
     maxMessages: number;
     pageSize?: number;
     query?: string;
@@ -246,7 +246,7 @@ async function getGmailMessage(
   messageId: string,
   options: {
     format: GmailMessageFormat;
-    metadataHeaders?: string[];
+    metadataHeaders?: unknown;
   },
 ): Promise<unknown> {
   return await gmailApi(
@@ -402,10 +402,15 @@ function clamp(value: number | undefined, min: number, max: number): number {
   return Math.max(min, Math.min(max, Math.trunc(value ?? min)));
 }
 
-function normalizeStringArray(values: string[] | undefined): string[] {
-  return (values ?? [])
-    .map((value) => value.trim())
-    .filter((value) => value.length > 0);
+function normalizeStringArray(value: unknown): string[] {
+  return Array.isArray(value)
+    ? value
+        .filter(
+          (item): item is string =>
+            typeof item === "string" && item.trim().length > 0,
+        )
+        .map((item) => item.trim())
+    : [];
 }
 
 function removeEmptyValues(
diff --git a/test/connector-config-overrides.test.ts b/test/connector-config-overrides.test.ts
index ba1b8153..5935d01e 100644
--- a/test/connector-config-overrides.test.ts
+++ b/test/connector-config-overrides.test.ts
@@ -10,16 +10,20 @@ import { afterEach, describe, expect, test, vi } from "vitest";
 // `options.connectorConfig` overrides are merged on top of the on-disk config
 // — the bug this PR fixes, where gmail/slack/x silently ignored the overrides.
 //
-// Each connector short-circuits before any network call:
+// Most cases short-circuit before any network call:
 //   1. an `enabled` gate  -> returns status "skipped" when disabled
 //   2. a credentials gate -> returns status "error"   when the token env is unset
 // so the observable effect of the merge is which gate the run stops at, with no
-// `fetch` involved.
+// `fetch` involved. The malformed Gmail array test stubs `fetch` explicitly.
 
 const originalHome = process.env.HOME;
 const tempHomes: string[] = [];
 
 const CONNECTOR_ENV_KEYS = [
+  "OPENWIKI_GMAIL_ACCESS_TOKEN",
+  "OPENWIKI_GMAIL_REFRESH_TOKEN",
+  "OPENWIKI_GMAIL_TOKEN_EXPIRES_AT",
+  "OPENWIKI_GMAIL_TOKEN_TYPE",
   "OPENWIKI_X_ACCESS_TOKEN",
   "OPENWIKI_SLACK_USER_TOKEN",
 ] as const;
@@ -47,6 +51,7 @@ async function writeConnectorConfig(
 
 afterEach(async () => {
   vi.resetModules();
+  vi.unstubAllGlobals();
 
   if (originalHome === undefined) {
     delete process.env.HOME;
@@ -168,4 +173,49 @@ describe("gmail connector honors options.connectorConfig", () => {
     // If the override were ignored (the bug), it would proceed past this gate.
     expect(result.status).toBe("skipped");
   });
+
+  test("ignores malformed non-array list config instead of crashing", async () => {
+    const home = await createTempHome();
+    await writeConnectorConfig(home, "google", {
+      enabled: true,
+      format: "metadata",
+      labelIds: "INBOX",
+      maxMessages: 1,
+      metadataHeaders: "Subject",
+    });
+    const requests: string[] = [];
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: string | URL | Request) => {
+        const url = input instanceof Request ? input.url : String(input);
+        requests.push(url);
+
+        if (new URL(url).pathname.endsWith("/messages")) {
+          return new Response(JSON.stringify({ messages: [{ id: "msg-1" }] }), {
+            headers: { "Content-Type": "application/json" },
+            status: 200,
+          });
+        }
+
+        return new Response(JSON.stringify({ id: "msg-1" }), {
+          headers: { "Content-Type": "application/json" },
+          status: 200,
+        });
+      }),
+    );
+    const connector = await loadGmailConnector(home);
+    process.env.OPENWIKI_GMAIL_ACCESS_TOKEN = "gmail-access-token";
+    process.env.OPENWIKI_GMAIL_REFRESH_TOKEN = "gmail-refresh-token";
+
+    const result = await connector.ingest();
+
+    expect(result.status).toBe("success");
+    expect(requests).toHaveLength(2);
+    expect(new URL(requests[0] ?? "").searchParams.getAll("labelIds")).toEqual(
+      [],
+    );
+    expect(
+      new URL(requests[1] ?? "").searchParams.getAll("metadataHeaders"),
+    ).toEqual([]);
+  });
 });