diff --git a/.evergreen/resync-specs.sh b/.evergreen/resync-specs.sh
index 7271e8d46..ac6944972 100755
--- a/.evergreen/resync-specs.sh
+++ b/.evergreen/resync-specs.sh
@@ -137,6 +137,9 @@ do
     srv|SRV|initial-dns-seedlist-discovery|srv_seedlist)
       cpjson initial-dns-seedlist-discovery/tests/ srv_seedlist
       ;;
+    read-write-concern|read_write_concern)
+      cpjson read-write-concern/tests/operation read_write_concern/operation
+      ;;
     retryable-reads|retryable_reads)
       cpjson retryable-reads/tests/ retryable_reads
       ;;
diff --git a/test/read_write_concern/operation/default-write-concern-2.6.json b/test/read_write_concern/operation/default-write-concern-2.6.json
index c623298cd..0d8f9c98a 100644
--- a/test/read_write_concern/operation/default-write-concern-2.6.json
+++ b/test/read_write_concern/operation/default-write-concern-2.6.json
@@ -1,53 +1,93 @@
 {
-  "data": [
-    {
-      "_id": 1,
-      "x": 11
-    },
-    {
-      "_id": 2,
-      "x": 22
-    }
-  ],
-  "collection_name": "default_write_concern_coll",
-  "database_name": "default_write_concern_db",
-  "runOn": [
+  "description": "default-write-concern-2.6",
+  "schemaVersion": "1.0",
+  "runOnRequirements": [
     {
       "minServerVersion": "2.6"
     }
   ],
+  "createEntities": [
+    {
+      "client": {
+        "id": "client0",
+        "observeEvents": [
+          "commandStartedEvent"
+        ]
+      }
+    },
+    {
+      "database": {
+        "id": "database0",
+        "client": "client0",
+        "databaseName": "default-write-concern-tests",
+        "databaseOptions": {
+          "writeConcern": {}
+        }
+      }
+    },
+    {
+      "collection": {
+        "id": "collection0",
+        "database": "database0",
+        "collectionName": "coll",
+        "collectionOptions": {
+          "writeConcern": {}
+        }
+      }
+    }
+  ],
+  "initialData": [
+    {
+      "collectionName": "coll",
+      "databaseName": "default-write-concern-tests",
+      "documents": [
+        {
+          "_id": 1,
+          "x": 11
+        },
+        {
+          "_id": 2,
+          "x": 22
+        }
+      ]
+    }
+  ],
   "tests": [
     {
       "description": "DeleteOne omits default write concern",
       "operations": [
         {
           "name": "deleteOne",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {}
           },
-          "result": {
+          "expectResult": {
             "deletedCount": 1
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "delete": "default_write_concern_coll",
-              "deletes": [
-                {
-                  "q": {},
-                  "limit": 1
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "delete": "coll",
+                  "deletes": [
+                    {
+                      "q": {},
+                      "limit": 1
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
                 }
-              ],
-              "writeConcern": null
+              }
             }
-          }
+          ]
         }
       ]
     },
@@ -56,32 +96,36 @@
       "operations": [
         {
           "name": "deleteMany",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {}
           },
-          "result": {
+          "expectResult": {
             "deletedCount": 2
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "delete": "default_write_concern_coll",
-              "deletes": [
-                {
-                  "q": {},
-                  "limit": 0
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "delete": "coll",
+                  "deletes": [
+                    {
+                      "q": {},
+                      "limit": 0
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
                 }
-              ],
-              "writeConcern": null
+              }
             }
-          }
+          ]
         }
       ]
     },
@@ -90,30 +134,24 @@
       "operations": [
         {
           "name": "bulkWrite",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "ordered": true,
             "requests": [
               {
-                "name": "deleteMany",
-                "arguments": {
+                "deleteMany": {
                   "filter": {}
                 }
               },
               {
-                "name": "insertOne",
-                "arguments": {
+                "insertOne": {
                   "document": {
                     "_id": 1
                   }
                 }
               },
               {
-                "name": "updateOne",
-                "arguments": {
+                "updateOne": {
                   "filter": {
                     "_id": 1
                   },
@@ -125,16 +163,14 @@
                 }
               },
               {
-                "name": "insertOne",
-                "arguments": {
+                "insertOne": {
                   "document": {
                     "_id": 2
                   }
                 }
               },
               {
-                "name": "replaceOne",
-                "arguments": {
+                "replaceOne": {
                   "filter": {
                     "_id": 1
                   },
@@ -144,16 +180,14 @@
                 }
               },
               {
-                "name": "insertOne",
-                "arguments": {
+                "insertOne": {
                   "document": {
                     "_id": 3
                   }
                 }
               },
               {
-                "name": "updateMany",
-                "arguments": {
+                "updateMany": {
                   "filter": {
                     "_id": 1
                   },
@@ -165,8 +199,7 @@
                 }
               },
               {
-                "name": "deleteOne",
-                "arguments": {
+                "deleteOne": {
                   "filter": {
                     "_id": 3
                   }
@@ -176,10 +209,177 @@
           }
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "default_write_concern_coll",
-          "data": [
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "delete": "coll",
+                  "deletes": [
+                    {
+                      "q": {},
+                      "limit": 0
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "insert": "coll",
+                  "documents": [
+                    {
+                      "_id": 1
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 1
+                      },
+                      "u": {
+                        "$set": {
+                          "x": 1
+                        }
+                      },
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      },
+                      "multi": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "insert": "coll",
+                  "documents": [
+                    {
+                      "_id": 2
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 1
+                      },
+                      "u": {
+                        "x": 2
+                      },
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      },
+                      "multi": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "insert": "coll",
+                  "documents": [
+                    {
+                      "_id": 3
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 1
+                      },
+                      "u": {
+                        "$set": {
+                          "x": 3
+                        }
+                      },
+                      "multi": true,
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "delete": "coll",
+                  "deletes": [
+                    {
+                      "q": {
+                        "_id": 3
+                      },
+                      "limit": 1
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            }
+          ]
+        }
+      ],
+      "outcome": [
+        {
+          "collectionName": "coll",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 1,
               "x": 3
@@ -189,136 +389,6 @@
             }
           ]
         }
-      },
-      "expectations": [
-        {
-          "command_started_event": {
-            "command": {
-              "delete": "default_write_concern_coll",
-              "deletes": [
-                {
-                  "q": {},
-                  "limit": 0
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "insert": "default_write_concern_coll",
-              "documents": [
-                {
-                  "_id": 1
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 1
-                  },
-                  "u": {
-                    "$set": {
-                      "x": 1
-                    }
-                  }
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "insert": "default_write_concern_coll",
-              "documents": [
-                {
-                  "_id": 2
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 1
-                  },
-                  "u": {
-                    "x": 2
-                  }
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "insert": "default_write_concern_coll",
-              "documents": [
-                {
-                  "_id": 3
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 1
-                  },
-                  "u": {
-                    "$set": {
-                      "x": 3
-                    }
-                  },
-                  "multi": true
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "delete": "default_write_concern_coll",
-              "deletes": [
-                {
-                  "q": {
-                    "_id": 3
-                  },
-                  "limit": 1
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        }
       ]
     },
     {
@@ -326,10 +396,7 @@
       "operations": [
         {
           "name": "insertOne",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "document": {
               "_id": 3
@@ -338,10 +405,7 @@
         },
         {
           "name": "insertMany",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "documents": [
               {
@@ -354,10 +418,51 @@
           }
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "default_write_concern_coll",
-          "data": [
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "insert": "coll",
+                  "documents": [
+                    {
+                      "_id": 3
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "insert": "coll",
+                  "documents": [
+                    {
+                      "_id": 4
+                    },
+                    {
+                      "_id": 5
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            }
+          ]
+        }
+      ],
+      "outcome": [
+        {
+          "collectionName": "coll",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 1,
               "x": 11
@@ -377,37 +482,6 @@
             }
           ]
         }
-      },
-      "expectations": [
-        {
-          "command_started_event": {
-            "command": {
-              "insert": "default_write_concern_coll",
-              "documents": [
-                {
-                  "_id": 3
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "insert": "default_write_concern_coll",
-              "documents": [
-                {
-                  "_id": 4
-                },
-                {
-                  "_id": 5
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        }
       ]
     },
     {
@@ -415,10 +489,7 @@
       "operations": [
         {
           "name": "updateOne",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 1
@@ -432,10 +503,7 @@
         },
         {
           "name": "updateMany",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 2
@@ -449,10 +517,7 @@
         },
         {
           "name": "replaceOne",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 2
@@ -463,10 +528,98 @@
           }
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "default_write_concern_coll",
-          "data": [
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 1
+                      },
+                      "u": {
+                        "$set": {
+                          "x": 1
+                        }
+                      },
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      },
+                      "multi": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 2
+                      },
+                      "u": {
+                        "$set": {
+                          "x": 2
+                        }
+                      },
+                      "multi": true,
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "update": "coll",
+                  "updates": [
+                    {
+                      "q": {
+                        "_id": 2
+                      },
+                      "u": {
+                        "x": 3
+                      },
+                      "upsert": {
+                        "$$unsetOrMatches": false
+                      },
+                      "multi": {
+                        "$$unsetOrMatches": false
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            }
+          ]
+        }
+      ],
+      "outcome": [
+        {
+          "collectionName": "coll",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 1,
               "x": 1
@@ -477,67 +630,6 @@
             }
           ]
         }
-      },
-      "expectations": [
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 1
-                  },
-                  "u": {
-                    "$set": {
-                      "x": 1
-                    }
-                  }
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 2
-                  },
-                  "u": {
-                    "$set": {
-                      "x": 2
-                    }
-                  },
-                  "multi": true
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "update": "default_write_concern_coll",
-              "updates": [
-                {
-                  "q": {
-                    "_id": 2
-                  },
-                  "u": {
-                    "x": 3
-                  }
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        }
       ]
     }
   ]
diff --git a/test/read_write_concern/operation/default-write-concern-3.2.json b/test/read_write_concern/operation/default-write-concern-3.2.json
index 04dd231f0..166a18491 100644
--- a/test/read_write_concern/operation/default-write-concern-3.2.json
+++ b/test/read_write_concern/operation/default-write-concern-3.2.json
@@ -1,31 +1,64 @@
 {
-  "data": [
-    {
-      "_id": 1,
-      "x": 11
-    },
-    {
-      "_id": 2,
-      "x": 22
-    }
-  ],
-  "collection_name": "default_write_concern_coll",
-  "database_name": "default_write_concern_db",
-  "runOn": [
+  "description": "default-write-concern-3.2",
+  "schemaVersion": "1.0",
+  "runOnRequirements": [
     {
       "minServerVersion": "3.2"
     }
   ],
+  "createEntities": [
+    {
+      "client": {
+        "id": "client0",
+        "observeEvents": [
+          "commandStartedEvent"
+        ]
+      }
+    },
+    {
+      "database": {
+        "id": "database0",
+        "client": "client0",
+        "databaseName": "default-write-concern-tests",
+        "databaseOptions": {
+          "writeConcern": {}
+        }
+      }
+    },
+    {
+      "collection": {
+        "id": "collection0",
+        "database": "database0",
+        "collectionName": "coll",
+        "collectionOptions": {
+          "writeConcern": {}
+        }
+      }
+    }
+  ],
+  "initialData": [
+    {
+      "collectionName": "coll",
+      "databaseName": "default-write-concern-tests",
+      "documents": [
+        {
+          "_id": 1,
+          "x": 11
+        },
+        {
+          "_id": 2,
+          "x": 22
+        }
+      ]
+    }
+  ],
   "tests": [
     {
       "description": "findAndModify operations omit default write concern",
       "operations": [
         {
           "name": "findOneAndUpdate",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 1
@@ -39,10 +72,7 @@
         },
         {
           "name": "findOneAndReplace",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 2
@@ -54,10 +84,7 @@
         },
         {
           "name": "findOneAndDelete",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "filter": {
               "_id": 2
@@ -65,60 +92,72 @@
           }
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "default_write_concern_coll",
-          "data": [
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "findAndModify": "coll",
+                  "query": {
+                    "_id": 1
+                  },
+                  "update": {
+                    "$set": {
+                      "x": 1
+                    }
+                  },
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "findAndModify": "coll",
+                  "query": {
+                    "_id": 2
+                  },
+                  "update": {
+                    "x": 2
+                  },
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "findAndModify": "coll",
+                  "query": {
+                    "_id": 2
+                  },
+                  "remove": true,
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            }
+          ]
+        }
+      ],
+      "outcome": [
+        {
+          "collectionName": "coll",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 1,
               "x": 1
             }
           ]
         }
-      },
-      "expectations": [
-        {
-          "command_started_event": {
-            "command": {
-              "findAndModify": "default_write_concern_coll",
-              "query": {
-                "_id": 1
-              },
-              "update": {
-                "$set": {
-                  "x": 1
-                }
-              },
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "findAndModify": "default_write_concern_coll",
-              "query": {
-                "_id": 2
-              },
-              "update": {
-                "x": 2
-              },
-              "writeConcern": null
-            }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "findAndModify": "default_write_concern_coll",
-              "query": {
-                "_id": 2
-              },
-              "remove": true,
-              "writeConcern": null
-            }
-          }
-        }
       ]
     }
   ]
diff --git a/test/read_write_concern/operation/default-write-concern-3.4.json b/test/read_write_concern/operation/default-write-concern-3.4.json
index 6519f6f08..e18cdfc0c 100644
--- a/test/read_write_concern/operation/default-write-concern-3.4.json
+++ b/test/read_write_concern/operation/default-write-concern-3.4.json
@@ -1,30 +1,68 @@
 {
-  "data": [
-    {
-      "_id": 1,
-      "x": 11
-    },
-    {
-      "_id": 2,
-      "x": 22
-    }
-  ],
-  "collection_name": "default_write_concern_coll",
-  "database_name": "default_write_concern_db",
-  "runOn": [
+  "description": "default-write-concern-3.4",
+  "schemaVersion": "1.4",
+  "runOnRequirements": [
     {
       "minServerVersion": "3.4"
     }
   ],
+  "createEntities": [
+    {
+      "client": {
+        "id": "client0",
+        "observeEvents": [
+          "commandStartedEvent"
+        ]
+      }
+    },
+    {
+      "database": {
+        "id": "database0",
+        "client": "client0",
+        "databaseName": "default-write-concern-tests",
+        "databaseOptions": {
+          "writeConcern": {}
+        }
+      }
+    },
+    {
+      "collection": {
+        "id": "collection0",
+        "database": "database0",
+        "collectionName": "coll",
+        "collectionOptions": {
+          "writeConcern": {}
+        }
+      }
+    }
+  ],
+  "initialData": [
+    {
+      "collectionName": "coll",
+      "databaseName": "default-write-concern-tests",
+      "documents": [
+        {
+          "_id": 1,
+          "x": 11
+        },
+        {
+          "_id": 2,
+          "x": 22
+        }
+      ]
+    }
+  ],
   "tests": [
     {
       "description": "Aggregate with $out omits default write concern",
+      "runOnRequirements": [
+        {
+          "serverless": "forbid"
+        }
+      ],
       "operations": [
         {
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "name": "aggregate",
           "arguments": {
             "pipeline": [
@@ -42,77 +80,89 @@
           }
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "other_collection_name",
-          "data": [
+      "expectEvents": [
+        {
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "aggregate": "coll",
+                  "pipeline": [
+                    {
+                      "$match": {
+                        "_id": {
+                          "$gt": 1
+                        }
+                      }
+                    },
+                    {
+                      "$out": "other_collection_name"
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
+            }
+          ]
+        }
+      ],
+      "outcome": [
+        {
+          "collectionName": "other_collection_name",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 2,
               "x": 22
             }
           ]
         }
-      },
-      "expectations": [
-        {
-          "command_started_event": {
-            "command": {
-              "aggregate": "default_write_concern_coll",
-              "pipeline": [
-                {
-                  "$match": {
-                    "_id": {
-                      "$gt": 1
-                    }
-                  }
-                },
-                {
-                  "$out": "other_collection_name"
-                }
-              ],
-              "writeConcern": null
-            }
-          }
-        }
       ]
     },
     {
       "description": "RunCommand with a write command omits default write concern (runCommand should never inherit write concern)",
       "operations": [
         {
-          "object": "database",
-          "databaseOptions": {
-            "writeConcern": {}
-          },
+          "object": "database0",
           "name": "runCommand",
-          "command_name": "delete",
           "arguments": {
             "command": {
-              "delete": "default_write_concern_coll",
+              "delete": "coll",
               "deletes": [
                 {
                   "q": {},
                   "limit": 1
                 }
               ]
-            }
+            },
+            "commandName": "delete"
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "delete": "default_write_concern_coll",
-              "deletes": [
-                {
-                  "q": {},
-                  "limit": 1
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "delete": "coll",
+                  "deletes": [
+                    {
+                      "q": {},
+                      "limit": 1
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
+                  }
                 }
-              ],
-              "writeConcern": null
+              }
             }
-          }
+          ]
         }
       ]
     },
@@ -120,10 +170,7 @@
       "description": "CreateIndex and dropIndex omits default write concern",
       "operations": [
         {
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "name": "createIndex",
           "arguments": {
             "keys": {
@@ -132,53 +179,61 @@
           }
         },
         {
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "name": "dropIndex",
           "arguments": {
             "name": "x_1"
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "createIndexes": "default_write_concern_coll",
-              "indexes": [
-                {
-                  "name": "x_1",
-                  "key": {
-                    "x": 1
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "createIndexes": "coll",
+                  "indexes": [
+                    {
+                      "name": "x_1",
+                      "key": {
+                        "x": 1
+                      }
+                    }
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
                   }
                 }
-              ],
-              "writeConcern": null
+              }
+            },
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "dropIndexes": "coll",
+                  "index": "x_1",
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
             }
-          }
-        },
-        {
-          "command_started_event": {
-            "command": {
-              "dropIndexes": "default_write_concern_coll",
-              "index": "x_1",
-              "writeConcern": null
-            }
-          }
+          ]
         }
       ]
     },
     {
       "description": "MapReduce omits default write concern",
+      "runOnRequirements": [
+        {
+          "serverless": "forbid"
+        }
+      ],
       "operations": [
         {
           "name": "mapReduce",
-          "object": "collection",
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "arguments": {
             "map": {
               "$code": "function inc() { return emit(0, this.x + 1) }"
@@ -192,23 +247,30 @@
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "mapReduce": "default_write_concern_coll",
-              "map": {
-                "$code": "function inc() { return emit(0, this.x + 1) }"
-              },
-              "reduce": {
-                "$code": "function sum(key, values) { return values.reduce((acc, x) => acc + x); }"
-              },
-              "out": {
-                "inline": 1
-              },
-              "writeConcern": null
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "mapReduce": "coll",
+                  "map": {
+                    "$code": "function inc() { return emit(0, this.x + 1) }"
+                  },
+                  "reduce": {
+                    "$code": "function sum(key, values) { return values.reduce((acc, x) => acc + x); }"
+                  },
+                  "out": {
+                    "inline": 1
+                  },
+                  "writeConcern": {
+                    "$$exists": false
+                  }
+                }
+              }
             }
-          }
+          ]
         }
       ]
     }
diff --git a/test/read_write_concern/operation/default-write-concern-4.2.json b/test/read_write_concern/operation/default-write-concern-4.2.json
index fef192d1a..e8bb78d91 100644
--- a/test/read_write_concern/operation/default-write-concern-4.2.json
+++ b/test/read_write_concern/operation/default-write-concern-4.2.json
@@ -1,33 +1,63 @@
 {
-  "data": [
-    {
-      "_id": 1,
-      "x": 11
-    },
-    {
-      "_id": 2,
-      "x": 22
-    }
-  ],
-  "collection_name": "default_write_concern_coll",
-  "database_name": "default_write_concern_db",
-  "runOn": [
+  "description": "default-write-concern-4.2",
+  "schemaVersion": "1.0",
+  "runOnRequirements": [
     {
       "minServerVersion": "4.2"
     }
   ],
+  "createEntities": [
+    {
+      "client": {
+        "id": "client0",
+        "observeEvents": [
+          "commandStartedEvent"
+        ]
+      }
+    },
+    {
+      "database": {
+        "id": "database0",
+        "client": "client0",
+        "databaseName": "default-write-concern-tests",
+        "databaseOptions": {
+          "writeConcern": {}
+        }
+      }
+    },
+    {
+      "collection": {
+        "id": "collection0",
+        "database": "database0",
+        "collectionName": "coll",
+        "collectionOptions": {
+          "writeConcern": {}
+        }
+      }
+    }
+  ],
+  "initialData": [
+    {
+      "collectionName": "coll",
+      "databaseName": "default-write-concern-tests",
+      "documents": [
+        {
+          "_id": 1,
+          "x": 11
+        },
+        {
+          "_id": 2,
+          "x": 22
+        }
+      ]
+    }
+  ],
   "tests": [
     {
       "description": "Aggregate with $merge omits default write concern",
       "operations": [
         {
-          "object": "collection",
-          "databaseOptions": {
-            "writeConcern": {}
-          },
-          "collectionOptions": {
-            "writeConcern": {}
-          },
+          "object": "collection0",
           "name": "aggregate",
           "arguments": {
             "pipeline": [
@@ -47,41 +77,49 @@
           }
         }
       ],
-      "expectations": [
+      "expectEvents": [
         {
-          "command_started_event": {
-            "command": {
-              "aggregate": "default_write_concern_coll",
-              "pipeline": [
-                {
-                  "$match": {
-                    "_id": {
-                      "$gt": 1
+          "client": "client0",
+          "events": [
+            {
+              "commandStartedEvent": {
+                "command": {
+                  "aggregate": "coll",
+                  "pipeline": [
+                    {
+                      "$match": {
+                        "_id": {
+                          "$gt": 1
+                        }
+                      }
+                    },
+                    {
+                      "$merge": {
+                        "into": "other_collection_name"
+                      }
                     }
-                  }
-                },
-                {
-                  "$merge": {
-                    "into": "other_collection_name"
+                  ],
+                  "writeConcern": {
+                    "$$exists": false
                   }
                 }
-              ],
-              "writeConcern": null
+              }
             }
-          }
+          ]
         }
       ],
-      "outcome": {
-        "collection": {
-          "name": "other_collection_name",
-          "data": [
+      "outcome": [
+        {
+          "collectionName": "other_collection_name",
+          "databaseName": "default-write-concern-tests",
+          "documents": [
             {
               "_id": 2,
               "x": 22
             }
           ]
         }
-      }
+      ]
     }
   ]
 }
diff --git a/test/test_read_write_concern_spec.py b/test/test_read_write_concern_spec.py
index 34aa1f754..3e37e8f9a 100644
--- a/test/test_read_write_concern_spec.py
+++ b/test/test_read_write_concern_spec.py
@@ -23,14 +23,13 @@ import warnings
 sys.path[0:0] = [""]
 
 from test import IntegrationTest, client_context, unittest
+from test.unified_format import generate_test_classes
 from test.utils import (
     EventListener,
-    SpecTestCreator,
     disable_replication,
     enable_replication,
     rs_or_single_client,
 )
-from test.utils_spec_runner import SpecRunner
 
 from pymongo import DESCENDING
 from pymongo.errors import (
@@ -321,25 +320,15 @@ def create_tests():
 create_tests()
 
 
-class TestOperation(SpecRunner):
-    # Location of JSON test specifications.
-    TEST_PATH = os.path.join(_TEST_PATH, "operation")
-
-    def get_outcome_coll_name(self, outcome, collection):
-        """Spec says outcome has an optional 'collection.name'."""
-        return outcome["collection"].get("name", collection.name)
-
-
-def create_operation_test(scenario_def, test, name):
-    @client_context.require_test_commands
-    def run_scenario(self):
-        self.run_scenario(scenario_def, test)
-
-    return run_scenario
-
-
-test_creator = SpecTestCreator(create_operation_test, TestOperation, TestOperation.TEST_PATH)
-test_creator.create_tests()
+# Generate unified tests.
+# PyMongo does not support MapReduce.
+globals().update(
+    generate_test_classes(
+        os.path.join(_TEST_PATH, "operation"),
+        module=__name__,
+        expected_failures=["MapReduce .*"],
+    )
+)
 
 
 if __name__ == "__main__":
diff --git a/test/test_retryable_reads_unified.py b/test/test_retryable_reads_unified.py
index d33abd596..3f8740cf4 100644
--- a/test/test_retryable_reads_unified.py
+++ b/test/test_retryable_reads_unified.py
@@ -27,7 +27,7 @@ from test.unified_format import generate_test_classes
 TEST_PATH = Path(__file__).parent / "retryable_reads/unified"
 
 # Generate unified tests.
-# PyMongo does not supportMapReduce, ListDatabaseObjects or ListCollectionObjects.
+# PyMongo does not support MapReduce, ListDatabaseObjects or ListCollectionObjects.
 globals().update(
     generate_test_classes(
         TEST_PATH,