diff --git a/apps/web/src/components/chat/AssistantCitationChip.tsx b/apps/web/src/components/chat/AssistantCitationChip.tsx
index ccfd746666a4..9b1469c9b00d 100644
--- a/apps/web/src/components/chat/AssistantCitationChip.tsx
+++ b/apps/web/src/components/chat/AssistantCitationChip.tsx
@@ -22,6 +22,7 @@ import {
 import { Tooltip, TooltipPopup, TooltipTrigger } from "../ui/tooltip";
 import { Popover, PopoverPopup, PopoverTrigger } from "../ui/popover";
 import { AssistantCitationCommentEditor } from "./AssistantCitationCommentEditor";
+import { resolveAssistantCitationCommentDismissal } from "./assistantCitationCommentDismissal";
 import { observeAssistantCitationCommentSource } from "./AssistantCitationSource";
 import { composerFloatingLayerProps } from "./composerEventScope";
 
@@ -48,10 +49,25 @@ export function AssistantCitationChip({
 }) {
   const navigate = useNavigate();
   const commentInputRef = useRef<HTMLTextAreaElement>(null);
+  const draftCommentRef = useRef<string | null>(null);
   const commentOpen = commentEditor?.open ?? false;
   const sourceAnchor = commentEditor?.sourceAnchor;
+  useEffect(() => {
+    if (!commentOpen) draftCommentRef.current = null;
+  }, [commentOpen]);
+  const settleDraftOnClose = (reason: string): boolean => {
+    const dismissal = resolveAssistantCitationCommentDismissal({
+      reason,
+      draft: draftCommentRef.current,
+      savedComment: citation.comment,
+    });
+    if (dismissal.kind === "commit") return commentEditor?.onSave(dismissal.comment) ?? true;
+    return dismissal.kind !== "keep-open";
+  };
   const onSourceUnavailable = useEffectEvent(() => {
-    if (sourceAnchor) commentEditor?.onOpenChange(false);
+    if (!sourceAnchor) return;
+    settleDraftOnClose("none");
+    commentEditor?.onOpenChange(false);
   });
   useEffect(() => {
     if (!commentOpen) return;
@@ -129,7 +145,16 @@ export function AssistantCitationChip({
         </Tooltip>
       )}
       {commentEditor ? (
-        <Popover open={commentEditor.open} onOpenChange={commentEditor.onOpenChange}>
+        <Popover
+          open={commentEditor.open}
+          onOpenChange={(open, eventDetails) => {
+            if (!open && !settleDraftOnClose(eventDetails.reason)) {
+              eventDetails.cancel();
+              return;
+            }
+            commentEditor.onOpenChange(open);
+          }}
+        >
           <PopoverTrigger
             aria-label={citation.comment ? "Edit citation comment" : "Add comment to citation"}
             className={CITATION_ACTION_BUTTON_CLASS_NAME}
@@ -155,6 +180,9 @@ export function AssistantCitationChip({
                 key={serializeAssistantCitation(citation)}
                 citation={citation}
                 inputRef={commentInputRef}
+                onDraftChange={(comment) => {
+                  draftCommentRef.current = comment;
+                }}
                 onSubmit={(comment) => {
                   if (!commentEditor.onSave(comment)) return false;
                   commentEditor.onOpenChange(false);
diff --git a/apps/web/src/components/chat/AssistantCitationCommentEditor.tsx b/apps/web/src/components/chat/AssistantCitationCommentEditor.tsx
index 4dc422210de0..d9fd60645618 100644
--- a/apps/web/src/components/chat/AssistantCitationCommentEditor.tsx
+++ b/apps/web/src/components/chat/AssistantCitationCommentEditor.tsx
@@ -9,12 +9,14 @@ export function AssistantCitationCommentEditor({
   onSubmit,
   onSubmitAndSend,
   onCancel,
+  onDraftChange,
 }: {
   citation: AssistantCitation;
   inputRef?: Ref<HTMLTextAreaElement>;
   onSubmit: (comment: string) => boolean;
   onSubmitAndSend?: (comment: string) => boolean;
   onCancel: () => void;
+  onDraftChange?: (comment: string) => void;
 }) {
   const [comment, setComment] = useState(citation.comment ?? "");
   const commentTooLong = comment.length > ASSISTANT_CITATION_MAX_COMMENT_LENGTH;
@@ -51,7 +53,10 @@ export function AssistantCitationCommentEditor({
         rows={2}
         className="field-sizing-content block max-h-40 min-h-16 w-full resize-none bg-transparent px-1 py-1.5 text-base outline-none placeholder:text-muted-foreground sm:text-sm"
         value={comment}
-        onChange={(event) => setComment(event.currentTarget.value)}
+        onChange={(event) => {
+          setComment(event.currentTarget.value);
+          onDraftChange?.(event.currentTarget.value);
+        }}
         onKeyDown={(event) => {
           if (
             event.key === "Enter" &&
diff --git a/apps/web/src/components/chat/assistantCitationCommentDismissal.test.ts b/apps/web/src/components/chat/assistantCitationCommentDismissal.test.ts
new file mode 100644
index 000000000000..1f21677a5a82
--- /dev/null
+++ b/apps/web/src/components/chat/assistantCitationCommentDismissal.test.ts
@@ -0,0 +1,80 @@
+import { ASSISTANT_CITATION_MAX_COMMENT_LENGTH } from "@t3tools/contracts";
+import { describe, expect, it } from "vite-plus/test";
+
+import { resolveAssistantCitationCommentDismissal } from "./assistantCitationCommentDismissal";
+
+describe("resolveAssistantCitationCommentDismissal", () => {
+  it("commits typed text when the popover is dismissed by clicking away", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "outside-press",
+        draft: "needs a retry",
+        savedComment: undefined,
+      }),
+    ).toEqual({ kind: "commit", comment: "needs a retry" });
+  });
+
+  it("commits an edited comment when focus leaves the popover", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "focus-out",
+        draft: "second thought",
+        savedComment: "first thought",
+      }),
+    ).toEqual({ kind: "commit", comment: "second thought" });
+  });
+
+  it("closes without saving when nothing changed", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "outside-press",
+        draft: null,
+        savedComment: "kept",
+      }),
+    ).toEqual({ kind: "close" });
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "outside-press",
+        draft: "  kept ",
+        savedComment: "kept",
+      }),
+    ).toEqual({ kind: "close" });
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "outside-press",
+        draft: "kept",
+        savedComment: " kept ",
+      }),
+    ).toEqual({ kind: "close" });
+  });
+
+  it("clears a comment when the draft was emptied", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "trigger-press",
+        draft: "",
+        savedComment: "old",
+      }),
+    ).toEqual({ kind: "commit", comment: "" });
+  });
+
+  it("keeps Escape as an explicit discard", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "escape-key",
+        draft: "unsaved",
+        savedComment: undefined,
+      }),
+    ).toEqual({ kind: "close" });
+  });
+
+  it("keeps the popover open instead of dropping an over-length draft", () => {
+    expect(
+      resolveAssistantCitationCommentDismissal({
+        reason: "outside-press",
+        draft: "x".repeat(ASSISTANT_CITATION_MAX_COMMENT_LENGTH + 1),
+        savedComment: undefined,
+      }),
+    ).toEqual({ kind: "keep-open" });
+  });
+});
diff --git a/apps/web/src/components/chat/assistantCitationCommentDismissal.ts b/apps/web/src/components/chat/assistantCitationCommentDismissal.ts
new file mode 100644
index 000000000000..a6fe2ca3bcb6
--- /dev/null
+++ b/apps/web/src/components/chat/assistantCitationCommentDismissal.ts
@@ -0,0 +1,21 @@
+import { ASSISTANT_CITATION_MAX_COMMENT_LENGTH } from "@t3tools/contracts";
+
+export type AssistantCitationCommentDismissal =
+  | { kind: "commit"; comment: string }
+  | { kind: "close" }
+  | { kind: "keep-open" };
+
+export function resolveAssistantCitationCommentDismissal({
+  reason,
+  draft,
+  savedComment,
+}: {
+  reason: string;
+  draft: string | null;
+  savedComment: string | undefined;
+}): AssistantCitationCommentDismissal {
+  if (reason === "escape-key" || draft === null) return { kind: "close" };
+  if (draft.trim() === (savedComment ?? "").trim()) return { kind: "close" };
+  if (draft.length > ASSISTANT_CITATION_MAX_COMMENT_LENGTH) return { kind: "keep-open" };
+  return { kind: "commit", comment: draft };
+}