diff --git a/apps/cli/src/program.test.ts b/apps/cli/src/program.test.ts
index af5a162..7a92bfe 100644
--- a/apps/cli/src/program.test.ts
+++ b/apps/cli/src/program.test.ts
@@ -593,7 +593,7 @@ test("config set rejects invalid gmail.syncFilter values", async () => {
 
 		expect(exitCode).toBe(EXIT_CODES.CONFIG_ERROR);
 		expect(errors).toContain(
-			"gmail.syncFilter must be one of: primary, primary-important.",
+			"gmail.syncFilter must be one of: primary, primary-important, inbox.",
 		);
 	});
 });
diff --git a/packages/connector-gmail/src/index.test.ts b/packages/connector-gmail/src/index.test.ts
index 4a486ff..da8d508 100644
--- a/packages/connector-gmail/src/index.test.ts
+++ b/packages/connector-gmail/src/index.test.ts
@@ -135,7 +135,7 @@ function createRequest(
 	_adapter: GmailAdapter,
 	options: {
 		since?: string | null;
-		syncFilter?: "primary" | "primary-important";
+		syncFilter?: "primary" | "primary-important" | "inbox";
 		secrets?: SecretsStore;
 		resolvedAuth?: GoogleResolvedAuth | null;
 		persistSource?: (source: SourceSnapshot) => Promise<void>;
@@ -970,3 +970,118 @@ test("html stripping handles common markup cleanup", () => {
 		"Hello\nworld",
 	);
 });
+
+test("inbox sync filter passes syncFilter=inbox to listInboxMessageIds", async () => {
+	let requestedFilter: string | undefined;
+	const adapter = createAdapter({
+		async listInboxMessageIds(_credentials, syncFilter): Promise<string[]> {
+			requestedFilter = syncFilter;
+			return ["m1"];
+		},
+	});
+	const connector = createGmailConnector({ adapter });
+	await connector.sync(createRequest(adapter, { syncFilter: "inbox" }));
+
+	expect(requestedFilter).toBe("inbox");
+});
+
+test("inbox sync filter persists messages with INBOX but without CATEGORY_PERSONAL", async () => {
+	const persisted: string[] = [];
+	const deleted: string[] = [];
+	const adapter = createAdapter({
+		async listInboxMessageIds(): Promise<string[]> {
+			return ["m1", "m2"];
+		},
+		async getMessage(_credentials, messageId): Promise<GmailMessage | null> {
+			return messageId === "m1"
+				? createMessage("m1", { labelIds: ["INBOX", "CATEGORY_PROMOTIONS"] })
+				: createMessage("m2", { labelIds: ["INBOX", "CATEGORY_PERSONAL"] });
+		},
+	});
+	const connector = createGmailConnector({ adapter });
+
+	await connector.sync(
+		createRequest(adapter, {
+			syncFilter: "inbox",
+			persistSource: async (source) => {
+				persisted.push(source.sourceId);
+			},
+			deleteSource: async (sourceId) => {
+				deleted.push(sourceId);
+			},
+		}),
+	);
+
+	expect(persisted).toEqual(["m1", "m2"]);
+	expect(deleted).toEqual([]);
+});
+
+test("inbox sync filter deletes messages without INBOX label", async () => {
+	const persisted: string[] = [];
+	const deleted: string[] = [];
+	const writes: string[] = [];
+	const adapter = createAdapter({
+		async listHistory(): Promise<GmailHistoryResult> {
+			return {
+				history: [{ labelsRemoved: [{ message: { id: "m1" } }] }],
+			};
+		},
+		async getMessage(): Promise<GmailMessage | null> {
+			return createMessage("m1", { labelIds: ["CATEGORY_PROMOTIONS"] });
+		},
+	});
+	const connector = createGmailConnector({ adapter });
+
+	await connector.sync(
+		createRequest(adapter, {
+			since: JSON.stringify({ historyId: "250", syncFilter: "inbox" }),
+			syncFilter: "inbox",
+			persistSource: async (source) => {
+				persisted.push(source.sourceId);
+			},
+			deleteSource: async (sourceId) => {
+				deleted.push(sourceId);
+			},
+			io: {
+				write(line) {
+					writes.push(line);
+				},
+				error() {},
+			},
+		}),
+	);
+
+	expect(persisted).toEqual([]);
+	expect(deleted).toEqual(["m1"]);
+	expect(writes).toContain(
+		"Gmail message removed from the active inbox filter during sync: m1",
+	);
+});
+
+test("inbox cursor is accepted as valid and not treated as legacy", async () => {
+	let resetCalls = 0;
+	let inboxCalls = 0;
+	const adapter = createAdapter({
+		async listHistory(): Promise<GmailHistoryResult> {
+			return { history: [] };
+		},
+		async listInboxMessageIds(): Promise<string[]> {
+			inboxCalls += 1;
+			return [];
+		},
+	});
+	const connector = createGmailConnector({ adapter });
+
+	await connector.sync(
+		createRequest(adapter, {
+			since: JSON.stringify({ historyId: "250", syncFilter: "inbox" }),
+			syncFilter: "inbox",
+			resetIntegrationState: async () => {
+				resetCalls += 1;
+			},
+		}),
+	);
+
+	expect(resetCalls).toBe(0);
+	expect(inboxCalls).toBe(0);
+});
diff --git a/packages/connector-gmail/src/index.ts b/packages/connector-gmail/src/index.ts
index 6363340..00da9a6 100644
--- a/packages/connector-gmail/src/index.ts
+++ b/packages/connector-gmail/src/index.ts
@@ -557,15 +557,16 @@ function getGmailSyncFilter(request: ConnectorSyncRequest): GmailSyncFilter {
 		);
 	}
 
-	return request.integration.config.syncFilter === "primary-important"
-		? "primary-important"
-		: "primary";
+	const filter = request.integration.config.syncFilter;
+	if (filter === "primary-important") return "primary-important";
+	if (filter === "inbox") return "inbox";
+	return "primary";
 }
 
 function toSearchQuery(syncFilter: GmailSyncFilter): string {
-	return syncFilter === "primary-important"
-		? "category:primary label:important"
-		: "category:primary";
+	if (syncFilter === "primary-important") return "category:primary label:important";
+	if (syncFilter === "inbox") return "in:inbox";
+	return "category:primary";
 }
 
 function hasLabel(message: GmailMessage, label: string): boolean {
@@ -576,7 +577,11 @@ function isMessageEligible(
 	message: GmailMessage,
 	syncFilter: GmailSyncFilter,
 ): boolean {
-	if (!hasLabel(message, "INBOX") || !hasLabel(message, "CATEGORY_PERSONAL")) {
+	if (!hasLabel(message, "INBOX")) {
+		return false;
+	}
+
+	if (syncFilter !== "inbox" && !hasLabel(message, "CATEGORY_PERSONAL")) {
 		return false;
 	}
 
@@ -588,9 +593,9 @@ function isMessageEligible(
 }
 
 function formatRemovalReason(syncFilter: GmailSyncFilter): string {
-	return syncFilter === "primary-important"
-		? "Gmail message removed from the active primary+important filter during sync"
-		: "Gmail message removed from the active primary filter during sync";
+	if (syncFilter === "primary-important") return "Gmail message removed from the active primary+important filter during sync";
+	if (syncFilter === "inbox") return "Gmail message removed from the active inbox filter during sync";
+	return "Gmail message removed from the active primary filter during sync";
 }
 
 function encodeCursor(
@@ -623,7 +628,8 @@ function decodeCursor(
 
 		if (
 			parsed.syncFilter !== "primary" &&
-			parsed.syncFilter !== "primary-important"
+			parsed.syncFilter !== "primary-important" &&
+			parsed.syncFilter !== "inbox"
 		) {
 			return { historyId: null, resetReason: "legacy" };
 		}
@@ -1073,7 +1079,9 @@ function normalizeGmailIntegration(entry: Partial<IntegrationConfig>) {
 	const syncFilter: GmailSyncFilter =
 		config?.syncFilter === "primary-important"
 			? "primary-important"
-			: "primary";
+			: config?.syncFilter === "inbox"
+				? "inbox"
+				: "primary";
 	return [
 		{
 			id: entry.id,
@@ -1183,9 +1191,9 @@ export function createGmailConnectorPlugin(
 				{
 					key: "gmail.syncFilter",
 					async setValue(context, rawValue) {
-						if (rawValue !== "primary" && rawValue !== "primary-important") {
+						if (rawValue !== "primary" && rawValue !== "primary-important" && rawValue !== "inbox") {
 							throw new Error(
-								"gmail.syncFilter must be one of: primary, primary-important.",
+								"gmail.syncFilter must be one of: primary, primary-important, inbox.",
 							);
 						}
 						const integration = context.config.integrations.find(
diff --git a/packages/core/src/types.ts b/packages/core/src/types.ts
index e4d7734..36ec413 100644
--- a/packages/core/src/types.ts
+++ b/packages/core/src/types.ts
@@ -126,7 +126,7 @@ export type ConnectionConfig =
 	| NotionOAuthConnectionConfig
 	| AppleNotesLocalConnectionConfig;
 
-export type GmailSyncFilter = "primary" | "primary-important";
+export type GmailSyncFilter = "primary" | "primary-important" | "inbox";
 
 export interface GmailIntegrationSettings {
 	fetchConcurrency?: number;