diff --git a/src/agents/pi-embedded-block-chunker.ts b/src/agents/pi-embedded-block-chunker.ts
index 0416380beb0..d3b5638a087 100644
--- a/src/agents/pi-embedded-block-chunker.ts
+++ b/src/agents/pi-embedded-block-chunker.ts
@@ -24,6 +24,26 @@ type ParagraphBreak = {
   length: number;
 };
 
+function findSafeSentenceBreakIndex(
+  text: string,
+  fenceSpans: FenceSpan[],
+  minChars: number,
+): number {
+  const matches = text.matchAll(/[.!?](?=\s|$)/g);
+  let sentenceIdx = -1;
+  for (const match of matches) {
+    const at = match.index ?? -1;
+    if (at < minChars) {
+      continue;
+    }
+    const candidate = at + 1;
+    if (isSafeFenceBreak(fenceSpans, candidate)) {
+      sentenceIdx = candidate;
+    }
+  }
+  return sentenceIdx >= minChars ? sentenceIdx : -1;
+}
+
 export class EmbeddedBlockChunker {
   #buffer = "";
   readonly #chunking: BlockReplyChunking;
@@ -211,19 +231,8 @@ export class EmbeddedBlockChunker {
     }
 
     if (preference !== "newline") {
-      const matches = buffer.matchAll(/[.!?](?=\s|$)/g);
-      let sentenceIdx = -1;
-      for (const match of matches) {
-        const at = match.index ?? -1;
-        if (at < minChars) {
-          continue;
-        }
-        const candidate = at + 1;
-        if (isSafeFenceBreak(fenceSpans, candidate)) {
-          sentenceIdx = candidate;
-        }
-      }
-      if (sentenceIdx >= minChars) {
+      const sentenceIdx = findSafeSentenceBreakIndex(buffer, fenceSpans, minChars);
+      if (sentenceIdx !== -1) {
         return { index: sentenceIdx };
       }
     }
@@ -271,19 +280,8 @@ export class EmbeddedBlockChunker {
     }
 
     if (preference !== "newline") {
-      const matches = window.matchAll(/[.!?](?=\s|$)/g);
-      let sentenceIdx = -1;
-      for (const match of matches) {
-        const at = match.index ?? -1;
-        if (at < minChars) {
-          continue;
-        }
-        const candidate = at + 1;
-        if (isSafeFenceBreak(fenceSpans, candidate)) {
-          sentenceIdx = candidate;
-        }
-      }
-      if (sentenceIdx >= minChars) {
+      const sentenceIdx = findSafeSentenceBreakIndex(window, fenceSpans, minChars);
+      if (sentenceIdx !== -1) {
         return { index: sentenceIdx };
       }
     }