diff --git a/src/auto-reply/chunk.test.ts b/src/auto-reply/chunk.test.ts
index 4bd5dc4b65b2..33731b8fca27 100644
--- a/src/auto-reply/chunk.test.ts
+++ b/src/auto-reply/chunk.test.ts
@@ -6,6 +6,7 @@ import * as fences from "../../packages/markdown-core/src/fences.js";
 import { hasBalancedFences } from "../test-utils/chunk-test-helpers.js";
 import {
   chunkByNewline,
+  chunkByParagraph,
   chunkMarkdownText,
   chunkMarkdownTextWithMode,
   chunkText,
@@ -230,6 +231,37 @@ describe("chunkText", () => {
   ]);
 });
 
+describe("chunkByParagraph Unicode line/paragraph separators", () => {
+  it.each([
+    {
+      name: "treats lone U+2029 as a standalone paragraph boundary",
+      text: "paragraph one\u2029paragraph two starts here",
+      normalized: "paragraph one\n\nparagraph two starts here",
+      limit: 39,
+      expected: ["paragraph one", "paragraph two starts here"],
+    },
+    {
+      name: "treats lone U+2028 as a line break within one paragraph",
+      text: "paragraph one line\u2028still same paragraph",
+      normalized: "paragraph one line\nstill same paragraph",
+      limit: 50,
+      expected: ["paragraph one line\nstill same paragraph"],
+    },
+    {
+      name: "treats consecutive U+2028 and U+2029 as a paragraph boundary",
+      text: "paragraph one line\u2028\u2029paragraph two starts here",
+      normalized: "paragraph one line\n\nparagraph two starts here",
+      limit: 40,
+      expected: ["paragraph one line", "paragraph two starts here"],
+    },
+  ] as const)("$name", ({ text, normalized, limit, expected }) => {
+    const chunks = chunkByParagraph(text, limit);
+
+    expect(chunks).toEqual(expected);
+    expect(chunks).toEqual(chunkByParagraph(normalized, limit));
+  });
+});
+
 describe("resolveTextChunkLimit", () => {
   it.each([
     ...(["whatsapp", "telegram", "slack", "signal", "imessage", "discord"] as const).map(
diff --git a/src/auto-reply/chunk.ts b/src/auto-reply/chunk.ts
index 2b365765cc21..157d9d8872d1 100644
--- a/src/auto-reply/chunk.ts
+++ b/src/auto-reply/chunk.ts
@@ -207,8 +207,10 @@ export function chunkByParagraph(
   }
   const splitLongParagraphs = opts?.splitLongParagraphs !== false;
 
-  // Normalize to \n so blank line detection is consistent.
-  const normalized = text.replace(/\r\n?/g, "\n");
+  // U+2029 PARAGRAPH SEPARATOR maps to a blank-line boundary; U+2028 LINE
+  // SEPARATOR and CR/CRLF map to a single newline.
+  // Normalize in two steps so consecutive U+2028\u2029 also produces a blank line.
+  const normalized = text.replace(/\u2029/g, "\n\n").replace(/\r\n?|\u2028/g, "\n");
 
   // Fast-path: if there are no blank-line paragraph separators, do not split.
   // (We *do not* early-return based on `limit` — newline mode is about paragraph