Make agent validation self-correcting

src/lai_automation/prompt.py

@@ -71,3 +71,17 @@ Generated SQL, if relevant:
 
 Run focused tests while working. Leave the repository with the fix and regression test applied.
 """
+
+
+def build_retry_task(exception: Exception) -> str:
+    failure = redact(str(exception))[-6_000:]
+
+    return f"""The previous implementation failed isolated validation.
+
+Correct the existing changes using this test output:
+
+{failure}
+
+Keep the regression test meaningful. Do not remove or weaken tests, safety checks,
+authentication, authorization, SQL validation, or tenant isolation. Do not commit or push.
+"""