diff --git a/site/src/pages/AgentsPage/AgentChatPage.tsx b/site/src/pages/AgentsPage/AgentChatPage.tsx
index 0f6aaee97b..5226c27577 100644
--- a/site/src/pages/AgentsPage/AgentChatPage.tsx
+++ b/site/src/pages/AgentsPage/AgentChatPage.tsx
@@ -752,6 +752,7 @@ const AgentChatPage: FC = () => {
 					req: request,
 				});
 				store.clearStreamState();
+				store.setChatStatus("running");
 				setPendingEditMessageId(null);
 			} catch (error) {
 				setPendingEditMessageId(null);
@@ -790,6 +791,15 @@ const AgentChatPage: FC = () => {
 		// WebSocket stream.
 		if (!response.queued) {
 			store.clearStreamState();
+			// Optimistically set status to "running" so the
+			// "Thinking..." indicator appears immediately.
+			// The server accepted the message (not queued),
+			// so it will start processing. The WebSocket
+			// status:running event no-ops via the
+			// setChatStatus guard. If the server transitions
+			// to error/pending instead, the WebSocket event
+			// overrides this optimistic value.
+			store.setChatStatus("running");
 			if (response.message) {
 				store.upsertDurableMessage(response.message);
 			}
diff --git a/site/src/pages/AgentsPage/components/ChatConversation/chatStore.createStore.test.ts b/site/src/pages/AgentsPage/components/ChatConversation/chatStore.createStore.test.ts
index cd80e0c53e..99c009e52a 100644
--- a/site/src/pages/AgentsPage/components/ChatConversation/chatStore.createStore.test.ts
+++ b/site/src/pages/AgentsPage/components/ChatConversation/chatStore.createStore.test.ts
@@ -654,4 +654,25 @@ describe("selectIsAwaitingFirstStreamChunk", () => {
 		// we should not be in a "starting" state.
 		expect(selectIsAwaitingFirstStreamChunk(store.getSnapshot())).toBe(false);
 	});
+
+	it("returns true after optimistic send: clearStreamState + setChatStatus('running') + upsertDurableMessage", () => {
+		const store = createChatStore();
+		// Simulate a completed previous turn: assistant replied,
+		// then server transitioned to "pending".
+		store.upsertDurableMessage(makeMessage(1, "user", "first question"));
+		store.upsertDurableMessage(makeMessage(2, "assistant", "first answer"));
+		store.setChatStatus("pending");
+
+		// Verify baseline: not awaiting during pending.
+		expect(selectIsAwaitingFirstStreamChunk(store.getSnapshot())).toBe(false);
+
+		// Simulate handleSend after POST returns (non-queued).
+		// This is the exact sequence from AgentChatPage.tsx.
+		store.clearStreamState();
+		store.setChatStatus("running");
+		store.upsertDurableMessage(makeMessage(3, "user", "follow-up"));
+
+		// "Thinking..." should appear immediately.
+		expect(selectIsAwaitingFirstStreamChunk(store.getSnapshot())).toBe(true);
+	});
 });