diff --git a/packages/opencode/src/tool/edit.ts b/packages/opencode/src/tool/edit.ts
index d3883b53..1b31b0aa 100644
--- a/packages/opencode/src/tool/edit.ts
+++ b/packages/opencode/src/tool/edit.ts
@@ -188,7 +188,10 @@ export const LineTrimmedReplacer: Replacer = function* (content, find) {
 
       let matchEndIndex = matchStartIndex
       for (let k = 0; k < searchLines.length; k++) {
-        matchEndIndex += originalLines[i + k].length + 1
+        matchEndIndex += originalLines[i + k].length
+        if (k < searchLines.length - 1) {
+          matchEndIndex += 1 // Add newline character except for the last line
+        }
       }
 
       yield content.substring(matchStartIndex, matchEndIndex)