diff --git a/tests/fixtures/conformance/checkpoint/008_export_checkpoint_json_wrapper_shape.json b/tests/fixtures/conformance/checkpoint/008_export_checkpoint_json_wrapper_shape.json
new file mode 100644
index 0000000..869bc6c
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/008_export_checkpoint_json_wrapper_shape.json
@@ -0,0 +1,38 @@
+{
+  "id": "checkpoint_export_checkpoint_json_wrapper_shape",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "prelude": [
+    "set premise concise replies",
+    "use docker"
+  ],
+  "action": {
+    "fn": "export_checkpoint_json"
+  },
+  "expected": {
+    "payload_json_parseable": true,
+    "payload_object": {
+      "checkpoint_version": 1,
+      "authoritative_state": {
+        "premise": "concise replies",
+        "policies": {
+          "docker": "use"
+        },
+        "version": 2
+      },
+      "pending": null
+    },
+    "has_pending_clarification": false,
+    "state": {
+      "premise": "concise replies",
+      "policies": {
+        "docker": "use"
+      },
+      "version": 2
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/009_import_checkpoint_json_restores_authoritative_state_no_pending.json b/tests/fixtures/conformance/checkpoint/009_import_checkpoint_json_restores_authoritative_state_no_pending.json
new file mode 100644
index 0000000..05e43f1
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/009_import_checkpoint_json_restores_authoritative_state_no_pending.json
@@ -0,0 +1,39 @@
+{
+  "id": "checkpoint_import_checkpoint_json_restores_authoritative_state_no_pending",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "action": {
+    "fn": "import_checkpoint_json",
+    "payload": "{\"authoritative_state\":{\"policies\":{\"pytest\":\"use\"},\"premise\":\"baseline\",\"version\":2},\"checkpoint_version\":1,\"pending\":null}"
+  },
+  "expected": {
+    "has_pending_clarification": false,
+    "state": {
+      "premise": "baseline",
+      "policies": {
+        "pytest": "use"
+      },
+      "version": 2
+    },
+    "followup": {
+      "input": "yes",
+      "decision": {
+        "kind": "passthrough",
+        "state": null,
+        "prompt_to_user": null
+      },
+      "state": {
+        "premise": "baseline",
+        "policies": {
+          "pytest": "use"
+        },
+        "version": 2
+      },
+      "has_pending_clarification": false
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/010_checkpoint_json_round_trip_state_and_pending_parity.json b/tests/fixtures/conformance/checkpoint/010_checkpoint_json_round_trip_state_and_pending_parity.json
new file mode 100644
index 0000000..43b9809
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/010_checkpoint_json_round_trip_state_and_pending_parity.json
@@ -0,0 +1,37 @@
+{
+  "id": "checkpoint_checkpoint_json_round_trip_state_and_pending_parity",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "prelude": [
+    "use kubectl instead of docker"
+  ],
+  "action": {
+    "fn": "checkpoint_json_round_trip"
+  },
+  "expected": {
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    },
+    "has_pending_clarification": true,
+    "followup": {
+      "input": "maybe",
+      "decision": {
+        "kind": "clarify",
+        "state": null,
+        "prompt_to_user": "Did you mean to use \"kubectl\" instead?"
+      },
+      "state": {
+        "premise": null,
+        "policies": {},
+        "version": 2
+      },
+      "has_pending_clarification": true
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/011_pending_clarification_through_checkpoint_json_restore_yes_resolution.json b/tests/fixtures/conformance/checkpoint/011_pending_clarification_through_checkpoint_json_restore_yes_resolution.json
new file mode 100644
index 0000000..15a5f55
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/011_pending_clarification_through_checkpoint_json_restore_yes_resolution.json
@@ -0,0 +1,45 @@
+{
+  "id": "checkpoint_pending_clarification_through_checkpoint_json_restore_yes_resolution",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "prelude": [
+    "use kubectl instead of docker"
+  ],
+  "action": {
+    "fn": "checkpoint_json_round_trip"
+  },
+  "expected": {
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    },
+    "has_pending_clarification": true,
+    "followup": {
+      "input": "yes",
+      "decision": {
+        "kind": "update",
+        "state": {
+          "premise": null,
+          "policies": {
+            "kubectl": "use"
+          },
+          "version": 2
+        },
+        "prompt_to_user": null
+      },
+      "state": {
+        "premise": null,
+        "policies": {
+          "kubectl": "use"
+        },
+        "version": 2
+      },
+      "has_pending_clarification": false
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/012_import_checkpoint_json_malformed_rejected.json b/tests/fixtures/conformance/checkpoint/012_import_checkpoint_json_malformed_rejected.json
new file mode 100644
index 0000000..74a70ac
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/012_import_checkpoint_json_malformed_rejected.json
@@ -0,0 +1,25 @@
+{
+  "id": "checkpoint_import_checkpoint_json_malformed_rejected",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "action": {
+    "fn": "import_checkpoint_json",
+    "payload": "{"
+  },
+  "expected": {
+    "error": {
+      "type": "ValueError",
+      "message_contains": "Invalid JSON payload"
+    },
+    "has_pending_clarification": false,
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/013_import_checkpoint_json_invalid_shape_rejected.json b/tests/fixtures/conformance/checkpoint/013_import_checkpoint_json_invalid_shape_rejected.json
new file mode 100644
index 0000000..8f9c0c9
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/013_import_checkpoint_json_invalid_shape_rejected.json
@@ -0,0 +1,25 @@
+{
+  "id": "checkpoint_import_checkpoint_json_invalid_shape_rejected",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "action": {
+    "fn": "import_checkpoint_json",
+    "payload": "[]"
+  },
+  "expected": {
+    "error": {
+      "type": "ValueError",
+      "message_contains": "Invalid checkpoint payload"
+    },
+    "has_pending_clarification": false,
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/014_import_checkpoint_json_invalid_authoritative_state_rejected.json b/tests/fixtures/conformance/checkpoint/014_import_checkpoint_json_invalid_authoritative_state_rejected.json
new file mode 100644
index 0000000..338504c
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/014_import_checkpoint_json_invalid_authoritative_state_rejected.json
@@ -0,0 +1,25 @@
+{
+  "id": "checkpoint_import_checkpoint_json_invalid_authoritative_state_rejected",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "action": {
+    "fn": "import_checkpoint_json",
+    "payload": "{\"checkpoint_version\":1,\"authoritative_state\":{\"premise\":null,\"policies\":[],\"version\":2},\"pending\":null}"
+  },
+  "expected": {
+    "error": {
+      "type": "ValueError",
+      "message_contains": "Invalid state payload"
+    },
+    "has_pending_clarification": false,
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    }
+  }
+}
diff --git a/tests/fixtures/conformance/checkpoint/015_import_checkpoint_json_invalid_payload_is_all_or_nothing.json b/tests/fixtures/conformance/checkpoint/015_import_checkpoint_json_invalid_payload_is_all_or_nothing.json
new file mode 100644
index 0000000..67a1da4
--- /dev/null
+++ b/tests/fixtures/conformance/checkpoint/015_import_checkpoint_json_invalid_payload_is_all_or_nothing.json
@@ -0,0 +1,42 @@
+{
+  "id": "checkpoint_import_checkpoint_json_invalid_payload_is_all_or_nothing",
+  "kind": "checkpoint",
+  "initial_state": {
+    "premise": null,
+    "policies": {},
+    "version": 2
+  },
+  "prelude": [
+    "use kubectl instead of docker"
+  ],
+  "action": {
+    "fn": "import_checkpoint_json",
+    "payload": "{\"checkpoint_version\":1,\"authoritative_state\":{\"premise\":\"new premise\",\"policies\":{\"pytest\":\"use\"},\"version\":2},\"pending\":{\"kind\":\"replacement\",\"replacement\":{\"kind\":\"use_only\",\"new_item\":\"kubectl\",\"old_item\":\"docker\"},\"prompt_to_user\":\"confirm?\"}}"
+  },
+  "expected": {
+    "error": {
+      "type": "ValueError",
+      "message_contains": "Invalid checkpoint payload"
+    },
+    "has_pending_clarification": true,
+    "state": {
+      "premise": null,
+      "policies": {},
+      "version": 2
+    },
+    "followup": {
+      "input": "maybe",
+      "decision": {
+        "kind": "clarify",
+        "state": null,
+        "prompt_to_user": "Did you mean to use \"kubectl\" instead?"
+      },
+      "state": {
+        "premise": null,
+        "policies": {},
+        "version": 2
+      },
+      "has_pending_clarification": true
+    }
+  }
+}
diff --git a/tests/test_fixtures.py b/tests/test_fixtures.py
index 1b65897..92c2577 100644
--- a/tests/test_fixtures.py
+++ b/tests/test_fixtures.py
@@ -155,6 +155,24 @@ def test_checkpoint_fixtures() -> None:
             else:
                 with pytest.raises(ValueError, match=error["message_contains"]):
                     engine.import_checkpoint(payload)
+        elif fn == "export_checkpoint_json":
+            payload = engine.export_checkpoint_json()
+            if expected.get("payload_json_parseable"):
+                parsed = json.loads(payload)
+                assert parsed == expected["payload_object"], fixture_id
+        elif fn == "import_checkpoint_json":
+            payload = action["payload"]
+            error = expected.get("error")
+            if error is None:
+                engine.import_checkpoint_json(payload)
+            else:
+                with pytest.raises(ValueError, match=error["message_contains"]):
+                    engine.import_checkpoint_json(payload)
+        elif fn == "checkpoint_json_round_trip":
+            payload = engine.export_checkpoint_json()
+            target = create_engine()
+            target.import_checkpoint_json(payload)
+            engine = target
         else:
             raise AssertionError(f"Unknown checkpoint action: {fn}")