diff --git a/tests/canonical/conftest.py b/tests/canonical/conftest.py
index f9c612dc1..539ed0389 100644
--- a/tests/canonical/conftest.py
+++ b/tests/canonical/conftest.py
@@ -1,9 +1,9 @@
 """Pytest fixtures for the canonical acceptance harness.
 
 L0-a slice of #1170 — provides scenario discovery + per-scenario
-fixture loading. The actual ``ouroboros_auto`` invocation lands
-in a follow-up sub-PR; this PR ships the discovery contract,
-fixture-shape validation, and the runner skeleton.
+fixture loading. The live ``ouroboros_auto`` invocation is available
+through the explicit ``OUROBOROS_RUN_CANONICAL=1`` opt-in path; the
+default CI path remains hermetic and validates fixture shape.
 
 Per-scenario fixture is parametrized via ``pytest_generate_tests`` so
 adding a new ``tests/canonical/<slug>/`` directory automatically
diff --git a/tests/canonical/test_canonical.py b/tests/canonical/test_canonical.py
index d23766fc2..adaab536d 100644
--- a/tests/canonical/test_canonical.py
+++ b/tests/canonical/test_canonical.py
@@ -22,6 +22,8 @@
 
 import pytest
 
+from ouroboros.core.types import Result
+
 from .conftest import CanonicalScenario
 
 
@@ -244,9 +246,9 @@ async def test_scenario_live_run_or_skip(
 
     result = await _invoke_ouroboros_auto(scenario, workdir)
 
-    assert result.is_ok(), (
+    assert result.is_ok, (
         f"{scenario.slug}: ouroboros_auto returned MCP error: "
-        f"{result.unwrap_err() if not result.is_ok() else 'unknown'}"
+        f"{result.error if result.is_err else 'unknown'}"
     )
 
     tool_result = result.unwrap()
@@ -279,16 +281,6 @@ async def test_live_run_opt_in_invokes_auto_handler(
 
     calls: list[tuple[str, Path]] = []
 
-    class _Ok:
-        def is_ok(self) -> bool:
-            return True
-
-        def unwrap(self) -> object:
-            return _ToolResult()
-
-        def unwrap_err(self) -> str:
-            return "unexpected"
-
     class _ToolResult:
         is_error = False
         content: list[object] = []
@@ -298,9 +290,9 @@ class _ToolResult:
             "product_status": "verified_complete",
         }
 
-    async def fake_invoke(selected: CanonicalScenario, workdir: Path) -> _Ok:
+    async def fake_invoke(selected: CanonicalScenario, workdir: Path) -> Result[object, str]:
         calls.append((selected.slug, workdir))
-        return _Ok()
+        return Result.ok(_ToolResult())
 
     monkeypatch.setattr(
         "tests.canonical.test_canonical._invoke_ouroboros_auto",