diff --git a/datasette/telemetry_testing.py b/datasette/telemetry_testing.py
index 65a945b1..d9e953f1 100644
--- a/datasette/telemetry_testing.py
+++ b/datasette/telemetry_testing.py
@@ -385,6 +385,11 @@ def assert_package_never_imports_sdk(*module_names):
     rather than by grepping, so a lazy `import opentelemetry.sdk` inside a
     function body cannot slip past. A plugin should depend on
     `opentelemetry-api` only, exactly as Datasette core does.
+
+    Run the test that calls this early in your suite: on macOS/CPython 3.13
+    a process that has accumulated many threads can crash (SIGBUS) in
+    subprocess's fork+exec - Datasette's own conftest front-loads its
+    equivalent tests by name for exactly this reason.
     """
     imports = "; ".join(f"import {name}" for name in module_names)
     code = (
diff --git a/tests/conftest.py b/tests/conftest.py
index d3bbab1b..d886c5fe 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -185,6 +185,7 @@ def pytest_collection_modifyitems(config, items):
     # (SIGSEGV/SIGBUS inside _execute_child). Reproduces with any subprocess
     # call placed there, on an unmodified tree - running it first avoids it.
     move_to_front(items, "test_datasette_package_never_imports_the_sdk")
+    move_to_front(items, "test_kit_module_itself_never_imports_the_sdk")
     move_to_front(items, "test_no_provider_takes_the_fast_path")
 
 
diff --git a/tests/test_telemetry_testing_kit.py b/tests/test_telemetry_testing_kit.py
index cac55c19..d2123f7c 100644
--- a/tests/test_telemetry_testing_kit.py
+++ b/tests/test_telemetry_testing_kit.py
@@ -133,8 +133,16 @@ def test_linked_root_span_kwargs_with_no_current_span(otel_spans):
 
 
 def test_kit_module_itself_never_imports_the_sdk():
-    # The kit imports the SDK lazily, so a plugin importing it at module
-    # level does not violate the api-only dependency rule.
+    """
+    The kit imports the SDK lazily, so a plugin importing it at module
+    level does not violate the api-only dependency rule.
+
+    conftest.py's pytest_collection_modifyitems() moves this test to the
+    front of the run by name - if you rename it, rename it there too. Like
+    every subprocess-spawning test in this suite, running it late crashes
+    the interpreter on macOS/CPython 3.13 (SIGBUS in fork+exec once the
+    process holds enough threads) - see the comment there.
+    """
     assert_package_never_imports_sdk("datasette.telemetry_testing")