diff --git a/docs/ecosystem-pipeline.md b/docs/ecosystem-pipeline.md
index 639c2e1..62f0783 100644
--- a/docs/ecosystem-pipeline.md
+++ b/docs/ecosystem-pipeline.md
@@ -41,6 +41,11 @@ During migration, run in `report` mode so agents get the full drift list without
 stopping at the first failure. After the queues are done, CI should run the same
 pipeline in `gate` mode and block drift.
 
+The E2E stage executes `run-ecosystem-e2e.py`. Listing capabilities with
+`--list` is discovery only and cannot satisfy the gate. Until execution is
+wired, the stage correctly fails instead of reporting a passing E2E run.
+Run pipeline regression tests with `python3 -m unittest discover -s tests -v`.
+
 If a repo already has an active PR, the next agent cycle on that PR should treat
 pipeline compatibility as the first task. Do not expand unrelated feature scope
 until the PR either moves the repo toward the uniform target or explicitly records
diff --git a/scripts/ecosystem-pipeline.sh b/scripts/ecosystem-pipeline.sh
old mode 100755
new mode 100644
index 25f25c5..2ee526e
--- a/scripts/ecosystem-pipeline.sh
+++ b/scripts/ecosystem-pipeline.sh
@@ -38,7 +38,7 @@ run_repo() {
 }
 
 run_e2e() {
-  run_step e2e-scenarios python3 "$ROOT/scripts/run-ecosystem-e2e.py" --list
+  run_step e2e-scenarios python3 "$ROOT/scripts/run-ecosystem-e2e.py"
 }
 
 case "$MODE" in
diff --git a/tests/test_pipeline.py b/tests/test_pipeline.py
new file mode 100644
index 0000000..9a5fe8f
--- /dev/null
+++ b/tests/test_pipeline.py
@@ -0,0 +1,60 @@
+"""Check that pipeline status reflects executed scenarios, not discovery."""
+
+import shutil
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+class PipelineTests(unittest.TestCase):
+    def run_pipeline(self, mode, scenario_exit):
+        with tempfile.TemporaryDirectory() as directory:
+            scripts = Path(directory) / "scripts"
+            scripts.mkdir()
+            pipeline = scripts / "ecosystem-pipeline.sh"
+            shutil.copyfile(ROOT / "scripts/ecosystem-pipeline.sh", pipeline)
+            # Discovery can succeed even when scenario execution fails.
+            (scripts / "run-ecosystem-e2e.py").write_text(
+                "import sys\n"
+                "if '--list' in sys.argv:\n"
+                "    print('scenario discovered')\n"
+                "    sys.exit(0)\n"
+                "print('scenario executed')\n"
+                f"sys.exit({scenario_exit})\n"
+            )
+            for checker in (
+                "check-ecosystem-binaries.py",
+                "check-architecture-uniformity.py",
+                "check-ecosystem-uniformity.py",
+                "run-ecosystem-verification.py",
+            ):
+                (scripts / checker).write_text("print('fixture check passed')\n")
+            return subprocess.run(
+                ["bash", str(pipeline), mode], capture_output=True, text=True
+            )
+
+    def test_failed_execution_cannot_pass_e2e_stage(self):
+        result = self.run_pipeline("e2e", 7)
+        self.assertEqual(result.returncode, 1)
+        self.assertIn("scenario executed", result.stdout)
+        self.assertIn("failed: e2e-scenarios (exit 7)", result.stderr)
+        self.assertNotIn("ecosystem pipeline passed", result.stdout)
+
+    def test_gate_propagates_scenario_exit_code(self):
+        result = self.run_pipeline("gate", 7)
+        self.assertEqual(result.returncode, 7)
+        self.assertIn("scenario executed", result.stdout)
+
+    def test_success_requires_execution(self):
+        result = self.run_pipeline("e2e", 0)
+        self.assertEqual(result.returncode, 0)
+        self.assertIn("scenario executed", result.stdout)
+        self.assertIn("ecosystem pipeline passed", result.stdout)
+
+
+if __name__ == "__main__":
+    unittest.main()