diff --git a/scripts/history_engine.py b/scripts/history_engine.py
index e9bd71d7..01204dfb 100644
--- a/scripts/history_engine.py
+++ b/scripts/history_engine.py
@@ -151,7 +151,12 @@ def collect_metrics(workspace: str, scan_result: Dict[str, Any]) -> Dict[str, An
     try:
         from circular_engine import detect_circular
         circ = detect_circular(workspace)
-        metrics["circular_deps_count"] = circ.get("cycle_count", 0)
+        # Bug: detect_circular() returns "total_cycles", never "cycle_count" —
+        # this always silently fell back to the 0 default regardless of how
+        # many cycles were actually found (found via real-codebase validation:
+        # circular_deps_count read 0 while the circular_deps list right below
+        # had 5 entries populated from the same detect_circular() call).
+        metrics["circular_deps_count"] = circ.get("total_cycles", 0)
         metrics["circular_deps"] = []
         cycles = circ.get("cycles", circ.get("chains", {}))
         if isinstance(cycles, dict):
diff --git a/scripts/impact_engine.py b/scripts/impact_engine.py
index 5538cb87..cafa7647 100755
--- a/scripts/impact_engine.py
+++ b/scripts/impact_engine.py
@@ -296,8 +296,19 @@ def analyze_impact(
         test_patterns = [
             f"{base}.test.ts", f"{base}.test.js", f"{base}.spec.ts", f"{base}.spec.js",
             f"{base}.test.tsx", f"{base}.spec.tsx",
-            f.replace(".rs", "_test.rs").replace(".py", "_test.py"),
         ]
+        # Rust/Python "_test" suffix convention — only applicable to files of
+        # that extension. Bug: str.replace() is a no-op when the extension
+        # doesn't match (e.g. a .ts file has no ".rs"/".py" substring), so the
+        # "pattern" silently degenerated into the original filename `f` itself
+        # — which trivially exists on disk, causing EVERY affected file to be
+        # misclassified as its own test file (found via real-codebase
+        # validation: impact --name signInWithGoogle listed calculator_widget.ts,
+        # errors.ts, sidepanel.ts as "tests", none of which are test files).
+        if f.endswith(".rs"):
+            test_patterns.append(f[:-3] + "_test.rs")
+        elif f.endswith(".py"):
+            test_patterns.append(f[:-3] + "_test.py")
         for tf in test_patterns:
             full_path = os.path.join(workspace, tf)
             if os.path.exists(full_path):