diff --git a/.config/dotnet-tools.json b/.config/dotnet-tools.json
index 3ef1073..f520528 100644
--- a/.config/dotnet-tools.json
+++ b/.config/dotnet-tools.json
@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "fantomas": {
-      "version": "5.1.3",
+      "version": "6.2.1",
       "commands": [
         "fantomas"
       ]
diff --git a/.gitignore b/.gitignore
index 7096b38..f21d1c6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -442,4 +442,7 @@ $RECYCLE.BIN/
 !.vscode/extensions.json
 
 *.fs.js
-*.mjs
\ No newline at end of file
+*.mjs
+
+# Direnv
+.envrc
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..1939523
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,64 @@
+{
+  "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1693611461,
+        "narHash": "sha256-aPODl8vAgGQ0ZYFIRisxYG5MOGSkIczvu2Cd8Gb9+1Y=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "7f53fdb7bdc5bb237da7fefef12d099e4fd611ca",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1695318763,
+        "narHash": "sha256-FHVPDRP2AfvsxAdc+AsgFJevMz5VBmnZglFUMlxBkcY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e12483116b3b51a185a33a272bf351e357ba9a99",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "dir": "lib",
+        "lastModified": 1693471703,
+        "narHash": "sha256-0l03ZBL8P1P6z8MaSDS/MvuU8E75rVxe5eE1N6gxeTo=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "3e52e76b70d5508f3cec70b882a29199f4d1ee85",
+        "type": "github"
+      },
+      "original": {
+        "dir": "lib",
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..eab72fa
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,25 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+  };
+  outputs = { self, nixpkgs, flake-parts }@inputs:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      perSystem = { system, pkgs, ... }: {
+        # Basically "patches" the `pkgs` input to `perSystem`
+        _module.args.pkgs = import inputs.nixpkgs {
+          inherit system;
+          config.allowUnfreePredicate = pkg: builtins.elem (nixpkgs.lib.getName pkg) [ "mongodb" "mongodb-compass" ];
+        };
+        formatter = pkgs.nixfmt;
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs;
+            [ dotnet-sdk ];
+          shellHook = ''
+            dotnet tool restore
+          '';
+        };
+      };
+      systems = [ "x86_64-linux" "x86_64-darwin" "aarch64-darwin" ];
+    };
+}
diff --git a/src/Mondocks.Net/Mondocks.Net.fsproj b/src/Mondocks.Net/Mondocks.Net.fsproj
index cf1b194..4411a51 100644
--- a/src/Mondocks.Net/Mondocks.Net.fsproj
+++ b/src/Mondocks.Net/Mondocks.Net.fsproj
@@ -19,4 +19,4 @@
   <ItemGroup>
     <ProjectReference Include="..\Mondocks\Mondocks.fsproj" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/Mondocks.Net/Types.fs b/src/Mondocks.Net/Types.fs
index 6f4b732..b2849aa 100644
--- a/src/Mondocks.Net/Types.fs
+++ b/src/Mondocks.Net/Types.fs
@@ -1,15 +1,22 @@
 namespace Mondocks.Types
 
+open MongoDB.Bson
 open MongoDB.Bson.Serialization.Attributes
 
 [<BsonIgnoreExtraElements>]
 type Cursor<'T> = { firstBatch: seq<'T>; ns: string }
 
+[<BsonIgnoreExtraElements>]
 type FindResult<'T> = { cursor: Cursor<'T>; ok: float }
 
 [<BsonIgnoreExtraElements>]
 type InsertResult = { n: int; ok: float }
 
+[<BsonIgnoreExtraElements>]
+type UpdateResult = { n: int; nModified: int; ok: float }
+
+[<BsonIgnoreExtraElements>]
+type DeleteResult = { n: int; ok: float }
 
 [<BsonIgnoreExtraElements>]
 type CreateIndexResult =
diff --git a/src/Mondocks/Database.fs b/src/Mondocks/Database.fs
index 5ac0c5e..3af047d 100644
--- a/src/Mondocks/Database.fs
+++ b/src/Mondocks/Database.fs
@@ -68,7 +68,7 @@ type IndexBuilder(name: string, serialize: SerializerFn) =
           wildcardProjection = None }
 
     member inline this.Run(state: Index<'PartialFilterExpression, 'StorageEngine, 'Weights, 'WildcardProjection>) =
-        this.Serialize { state with name = this.Name }
+        { state with name = this.Name }
 
     [<CustomOperation("key")>]
     member inline __.Key