diff --git a/ocr-service/engines/kraken.py b/ocr-service/engines/kraken.py
index a8c09f12..8deae3ef 100644
--- a/ocr-service/engines/kraken.py
+++ b/ocr-service/engines/kraken.py
@@ -104,7 +104,9 @@ def extract_region_text(image, x: float, y: float, w: float, h: float) -> str:
     if cw == 0 or ch == 0:
         return ""
 
-    # Single synthetic baseline at vertical midpoint, spanning full crop width
+    # Single synthetic baseline at vertical midpoint, spanning full crop width.
+    # Kraken's bounds check is >= (not >), so all coordinates must be < image
+    # dimension — use cw-1 / ch-1 to stay strictly inside.
     mid_y = ch // 2
     synthetic_seg = Segmentation(
         type="baselines",
@@ -114,8 +116,8 @@ def extract_region_text(image, x: float, y: float, w: float, h: float) -> str:
         lines=[
             BaselineLine(
                 id="line0",
-                baseline=[(0, mid_y), (cw, mid_y)],
-                boundary=[(0, 0), (cw, 0), (cw, ch), (0, ch)],
+                baseline=[(0, mid_y), (cw - 1, mid_y)],
+                boundary=[(0, 0), (cw - 1, 0), (cw - 1, ch - 1), (0, ch - 1)],
             )
         ],
         regions={},