diff --git a/AGENTS.md b/AGENTS.md
index 1f0eb082d..88c68684f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -41,6 +41,10 @@
 - Codex reasoning summaries can echo trailing empty HTML comments from model instructions. Keep
   that provider-specific cleanup in `src/ReasoningText.ts` across live deltas and history replay;
   do not filter assistant text, raw reasoning, or HTML globally in the client renderer.
+- App-server `warning` and `configWarning` notifications are structured ACP session info updates:
+  put `{ message, source }` under `_meta.codex.warning`. Never emit them as agent message text;
+  Lody persists that metadata as an `agent_warning` system notice, and text chunks would pollute
+  assistant history, generated titles, and replayed prompts.
 - Account rate-limit windows are dynamic. Read the full `account/rateLimits/read` snapshot when a
   session opens, merge sparse `account/rateLimits/updated` values into that snapshot, and preserve
   each window's `windowDurationMins` in the ACP extension. Never infer 5-hour/7-day meaning from
diff --git a/src/CodexEventHandler.ts b/src/CodexEventHandler.ts
index 6034fa6bd..43f8ae8db 100644
--- a/src/CodexEventHandler.ts
+++ b/src/CodexEventHandler.ts
@@ -437,11 +437,21 @@ export class CodexEventHandler {
 
     private async createConfigWarningEvent(event: ConfigWarningNotification): Promise<UpdateSessionEvent> {
         const detailsText = event.details ? `\n\n${event.details}` : "";
-        return createAgentTextMessageChunk(`Config warning: ${event.summary}${detailsText}\n\n`);
+        return this.createCodexSessionInfoUpdate({
+            warning: {
+                message: `${event.summary}${detailsText}`,
+                source: "configWarning",
+            },
+        });
     }
 
     private createWarningEvent(event: WarningNotification): UpdateSessionEvent {
-        return createAgentTextMessageChunk(`Warning: ${event.message}\n\n`);
+        return this.createCodexSessionInfoUpdate({
+            warning: {
+                message: event.message,
+                source: "warning",
+            },
+        });
     }
 
     private createModelReroutedEvent(event: ModelReroutedNotification): UpdateSessionEvent {
diff --git a/src/__tests__/CodexACPAgent/data/warning-events.json b/src/__tests__/CodexACPAgent/data/warning-events.json
new file mode 100644
index 000000000..766f0b9e1
--- /dev/null
+++ b/src/__tests__/CodexACPAgent/data/warning-events.json
@@ -0,0 +1,38 @@
+{
+  "method": "sessionUpdate",
+  "args": [
+    {
+      "sessionId": "test-session-id",
+      "update": {
+        "sessionUpdate": "session_info_update",
+        "_meta": {
+          "codex": {
+            "warning": {
+              "message": "Falling back from WebSockets to HTTPS transport. unexpected status 401",
+              "source": "warning"
+            }
+          }
+        }
+      }
+    }
+  ]
+}
+{
+  "method": "sessionUpdate",
+  "args": [
+    {
+      "sessionId": "test-session-id",
+      "update": {
+        "sessionUpdate": "session_info_update",
+        "_meta": {
+          "codex": {
+            "warning": {
+              "message": "Project configuration could not be loaded\n\nUsing the default configuration instead.",
+              "source": "configWarning"
+            }
+          }
+        }
+      }
+    }
+  ]
+}
\ No newline at end of file
diff --git a/src/__tests__/CodexACPAgent/warning-events.test.ts b/src/__tests__/CodexACPAgent/warning-events.test.ts
new file mode 100644
index 000000000..9fc89188d
--- /dev/null
+++ b/src/__tests__/CodexACPAgent/warning-events.test.ts
@@ -0,0 +1,48 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { ServerNotification } from "../../app-server";
+import {
+    createCodexMockTestFixture,
+    createTestSessionState,
+    setupPromptAndSendNotifications,
+    type CodexMockTestFixture,
+} from "../acp-test-utils";
+
+describe("CodexEventHandler - warning events", () => {
+    let mockFixture: CodexMockTestFixture;
+    const sessionId = "test-session-id";
+
+    beforeEach(() => {
+        mockFixture = createCodexMockTestFixture();
+        vi.clearAllMocks();
+    });
+
+    it("sends runtime and configuration warnings as structured session metadata", async () => {
+        const notifications: ServerNotification[] = [
+            {
+                method: "warning",
+                params: {
+                    threadId: sessionId,
+                    message: "Falling back from WebSockets to HTTPS transport. unexpected status 401",
+                },
+            },
+            {
+                method: "configWarning",
+                params: {
+                    summary: "Project configuration could not be loaded",
+                    details: "Using the default configuration instead.",
+                },
+            },
+        ];
+
+        await setupPromptAndSendNotifications(
+            mockFixture,
+            sessionId,
+            createTestSessionState({ sessionId }),
+            notifications,
+        );
+
+        await expect(mockFixture.getAcpConnectionDump([])).toMatchFileSnapshot(
+            "data/warning-events.json",
+        );
+    });
+});