diff --git a/.opencode/agents/ca-subtask-loop.md b/.opencode/agents/ca-subtask-loop.md
index 0c862f3ce..68d347aa7 100644
--- a/.opencode/agents/ca-subtask-loop.md
+++ b/.opencode/agents/ca-subtask-loop.md
@@ -109,6 +109,38 @@ Loop FOREVER:
     Pass: working directory, ref summary, subtask description,
           spec context, issue details, attempt_log (if attempt > 1)
 
+  # Step 1.5: Meaningful Change Verification
+  # Before running expensive quality gates, verify the implementer
+  # actually produced functional code changes — not just comments,
+  # whitespace, or empty diffs.
+  diff_output = run `git diff --stat` in working directory
+  full_diff = run `git diff` in working directory
+
+  reject_attempt = false
+  if diff_output is empty:
+    reject_attempt = true  # No changes at all
+  else:
+    # Analyze the diff content for meaningful changes
+    functional_lines = count lines in full_diff that:
+      - Are additions (start with "+") or deletions (start with "-")
+      - Are NOT comment-only lines (e.g., lines where the only content
+        after +/- is a Python comment starting with #)
+      - Are NOT whitespace-only changes
+      - Are NOT empty lines
+      - Are NOT import-only additions with no corresponding usage
+    if functional_lines < 3:
+      reject_attempt = true  # Trivially small or comment-only change
+
+  if reject_attempt:
+    Record in attempt_log:
+      "Attempt <N> rejected: implementer produced no meaningful code
+       changes (empty diff, comment-only, or fewer than 3 functional
+       lines). Skipping quality gates and escalating."
+    # Reset the working directory to avoid polluting the next attempt
+    run `git checkout -- .` in working directory
+    # Continue to next attempt (escalation) WITHOUT running quality gates
+    continue
+
   # Step 2: Write / Review ALL Tests IN PARALLEL
   # Launch ALL test writers simultaneously — do not serialize.
   invoke ALL of the following IN PARALLEL: