security(docs): hide runtime provider failures from users

tests/test_docs_context.py

@@ -151,6 +151,42 @@ class DocsContextTests(unittest.TestCase):
             "values": ["*.example.invalid"],
         })
 
+    def test_runtime_provider_failure_is_diagnostic_only(self) -> None:
+        def failing_provider(_context):
+            raise RuntimeError("sensitive provider detail")
+
+        registry = PlatformRegistry()
+        registry.register(ModuleManifest(
+            id="private-module",
+            name="Private module",
+            version="1.0.0",
+            documentation_providers=(failing_provider,),
+        ))
+        principal = FakePrincipal({"docs:documentation:read"})
+
+        user_layers = _classify_documentation(
+            registry,
+            principal,
+            settings=None,
+            session=None,
+            documentation_type="user",
+            locale="en",
+        )
+        admin_layers = _classify_documentation(
+            registry,
+            principal,
+            settings=None,
+            session=None,
+            documentation_type="admin",
+            locale="en",
+        )
+
+        self.assertFalse(any(user_layers.values()))
+        self.assertEqual(
+            [topic["id"] for topic in admin_layers["evidence"]],
+            ["private-module.runtime-documentation-unavailable"],
+        )
+
     def test_docs_default_to_user_and_admin_projection_requires_admin_authority(self) -> None:
         query_default = signature(docs_context).parameters["documentation_type"].default
         self.assertEqual(query_default.default, "user")
@@ -184,6 +220,7 @@ class DocsContextTests(unittest.TestCase):
         self.assertNotIn("scope_count", payload["actor"])
         self.assertEqual(payload["layers"]["configured"]["permissions"], [])
         self.assertEqual(payload["layers"]["available"]["routes"], [])
+        self.assertEqual(payload["layers"]["evidence"]["sources"], [])
 
     def test_topic_anchor_is_stable(self) -> None:
         self.assertEqual(