diff --git a/Makefile b/Makefile
index e336fbb..39cb6ab 100644
--- a/Makefile
+++ b/Makefile
@@ -28,7 +28,7 @@ serve:
 	uvicorn web.api:app --host 0.0.0.0 --port 8000
 
 test:
-	pytest tests/
+	python3.11 -m pytest tests/
 	cd $(FRONTEND_DIR) && npm run test
 
 deploy: build-frontend
diff --git a/tests/test_kin_103_worktrees.py b/tests/test_kin_103_worktrees.py
index ed0f0d5..0af8d4d 100644
--- a/tests/test_kin_103_worktrees.py
+++ b/tests/test_kin_103_worktrees.py
@@ -120,7 +120,7 @@ class TestCreateWorktree:
 
     @patch("subprocess.run")
     def test_create_worktree_sanitizes_step_name(self, mock_run, tmp_path):
-        """Слэши и пробелы в step_name заменяются на _ в branch name."""
+        """Слэши и пробелы в step_name заменяются на _ в branch name (decision #596)."""
         from core.worktree import create_worktree
         mock_run.return_value = _ok_run()
 
diff --git a/tests/test_kin_109_regression.py b/tests/test_kin_109_regression.py
new file mode 100644
index 0000000..519ab4b
--- /dev/null
+++ b/tests/test_kin_109_regression.py
@@ -0,0 +1,75 @@
+"""Regression tests for KIN-109:
+Auto-test должен использовать python3.11 вместо python3 (ссылается на 3.14).
+
+Root cause: Makefile test target used bare `pytest tests/` which resolves to the
+system pytest (Python 3.14). Tests written for Python 3.11 could fail under 3.14.
+
+Fix: Makefile test target changed to `python3.11 -m pytest tests/`.
+
+Coverage:
+(1) Makefile test target uses python3.11, not bare pytest
+(2) _detect_test_command still returns 'make test' for projects with Makefile
+"""
+
+import re
+from pathlib import Path
+
+
+# ---------------------------------------------------------------------------
+# (1) Makefile — test target uses python3.11 -m pytest
+# ---------------------------------------------------------------------------
+
+class TestMakefileTestTarget:
+    def test_makefile_test_uses_python311(self):
+        """Makefile test target must use python3.11 -m pytest, not bare pytest."""
+        makefile = Path(__file__).parent.parent / "Makefile"
+        assert makefile.is_file(), "Makefile must exist in project root"
+
+        content = makefile.read_text()
+
+        # Find test target block
+        m = re.search(r"^test\s*:.*?\n((?:\t.+\n?)*)", content, re.MULTILINE)
+        assert m is not None, "Makefile must have a 'test:' target"
+
+        test_body = m.group(1)
+        assert "python3.11 -m pytest" in test_body, (
+            f"Makefile test target must use 'python3.11 -m pytest', got:\n{test_body!r}"
+        )
+
+    def test_makefile_test_does_not_use_bare_pytest(self):
+        """Makefile test target must NOT use bare 'pytest' (would pick up Python 3.14)."""
+        makefile = Path(__file__).parent.parent / "Makefile"
+        content = makefile.read_text()
+
+        m = re.search(r"^test\s*:.*?\n((?:\t.+\n?)*)", content, re.MULTILINE)
+        assert m is not None
+        test_body = m.group(1)
+
+        # Bare pytest call (not prefixed by python3.11 -m)
+        bare_pytest = re.search(r"(?<!python3\.11 -m )(?<!\w)pytest\b", test_body)
+        assert bare_pytest is None, (
+            f"Makefile test target must not use bare 'pytest', got:\n{test_body!r}"
+        )
+
+
+# ---------------------------------------------------------------------------
+# (2) _detect_test_command still returns 'make test' for Makefile projects
+# ---------------------------------------------------------------------------
+
+class TestDetectTestCommandUnchanged:
+    def test_detect_returns_make_test_for_makefile(self, tmp_path):
+        """_detect_test_command must return 'make test' when Makefile has test target."""
+        from agents.runner import _detect_test_command
+
+        (tmp_path / "Makefile").write_text("test:\n\tpython3.11 -m pytest\n")
+        assert _detect_test_command(str(tmp_path)) == "make test"
+
+    def test_kin_project_detects_make_test(self):
+        """kin project itself must auto-detect 'make test' (has Makefile with test target)."""
+        from agents.runner import _detect_test_command
+
+        project_root = str(Path(__file__).parent.parent)
+        result = _detect_test_command(project_root)
+        assert result == "make test", (
+            f"kin project should detect 'make test', got {result!r}"
+        )