diff --git a/src/util/ijson.ts b/src/util/ijson.ts
index ec846b3f1..3e9fd1d9b 100644
--- a/src/util/ijson.ts
+++ b/src/util/ijson.ts
@@ -22,8 +22,10 @@ function formatPath(path: PathType): string {
             } else {
                 pathStr += "[" + JSON.stringify(pathPart) + "]";
             }
-        } else {
+        } else if (typeof pathPart === "number") {
             pathStr += "[" + pathPart + "]";
+        } else {
+            pathStr += ".*";
         }
     }
     return pathStr;
@@ -82,6 +84,18 @@ function combineFn_arrayAppend(oldVal: any, newVal: any, opts: SetPathOpts): any
     return oldVal;
 }
 
+function checkPath(path: PathType): boolean {
+    if (!isArray(path)) {
+        return false;
+    }
+    for (let pathPart of path) {
+        if (typeof pathPart !== "string" && typeof pathPart !== "number") {
+            return false;
+        }
+    }
+    return true;
+}
+
 function setPath(obj: any, path: PathType, value: any, opts: SetPathOpts) {
     if (opts == null) {
         opts = {};
@@ -89,6 +103,12 @@ function setPath(obj: any, path: PathType, value: any, opts: SetPathOpts) {
     if (opts.remove && value != null) {
         throw new Error("Cannot set value and remove at the same time");
     }
+    if (path == null) {
+        path = [];
+    }
+    if (!checkPath(path)) {
+        throw new Error("Invalid path: " + formatPath(path));
+    }
     return setPathInternal(obj, path, value, opts);
 }
 
@@ -194,5 +214,42 @@ function setPathInternal(obj: any, path: PathType, value: any, opts: SetPathOpts
     }
 }
 
+function getCommandPath(command: object): PathType {
+    if (command["path"] == null) {
+        return [];
+    }
+    return command["path"];
+}
+
+function applyCommand(data: any, command: any): any {
+    if (command == null) {
+        throw new Error("Invalid command (null)");
+    }
+    if (!isObject(command)) {
+        throw new Error("Invalid command (not an object): " + command);
+    }
+    const commandType = command.type;
+    if (commandType == null) {
+        throw new Error("Invalid command (no type): " + command);
+    }
+    const path = getCommandPath(command);
+    if (!checkPath(path)) {
+        throw new Error("Invalid command path: " + formatPath(path));
+    }
+    switch (commandType) {
+        case "set":
+            return setPath(data, path, command.value, null);
+
+        case "del":
+            return setPath(data, path, null, { remove: true });
+
+        case "append":
+            return setPath(data, path, command.value, { combinefn: combineFn_arrayAppend });
+
+        default:
+            throw new Error("Invalid command type: " + commandType);
+    }
+}
+
 export type { PathType, SetPathOpts };
-export { getPath, setPath, combineFn_arrayAppend };
+export { getPath, setPath, applyCommand, combineFn_arrayAppend };
diff --git a/waveshell/pkg/ijson/ijson.go b/waveshell/pkg/ijson/ijson.go
index 84812b7d9..bda7345b2 100644
--- a/waveshell/pkg/ijson/ijson.go
+++ b/waveshell/pkg/ijson/ijson.go
@@ -22,44 +22,10 @@ const (
 	AppendCommandStr = "append"
 )
 
-var _ = CommandType(SetCommand{})
-var _ = CommandType(DelCommand{})
-var _ = CommandType(AppendCommand{})
-
-type CommandType interface {
-	GetCommandType() string
-}
-
-type SetCommand struct {
-	Type string `json:"type"` // "set"
-	Path []any  `json:"path"` // each path entry must be either a string or int
-	Data any    `json:"data"` // data must be a valid JSON structure
-}
-
-func (c SetCommand) GetCommandType() string {
-	return SetCommandStr
-}
-
-// removes values from the state
-type DelCommand struct {
-	Type string `json:"type"` // "del"
-	Path []any  `json:"path"`
-}
-
-func (c DelCommand) GetCommandType() string {
-	return DelCommandStr
-}
-
-// appends to an array
-type AppendCommand struct {
-	Type string `json:"type"` // "append"
-	Path []any  `json:"path"`
-	Data any    `json:"data"`
-}
-
-func (c AppendCommand) GetCommandType() string {
-	return AppendCommandStr
-}
+// instead of defining structs for commands, we just define a command shape
+// set: type, path, value
+// del: type, path
+// arrayappend: type, path, value
 
 type PathError struct {
 	Err string
@@ -498,15 +464,50 @@ func DeepEqual(v1 any, v2 any) bool {
 	}
 }
 
-func ApplyCommand(data any, command CommandType, budget int) (any, error) {
-	switch command := command.(type) {
-	case SetCommand:
-		return SetPath(data, command.Path, command.Data, &SetPathOpts{Budget: budget})
-	case DelCommand:
-		return SetPath(data, command.Path, nil, &SetPathOpts{Remove: true, Budget: budget})
-	case AppendCommand:
-		return SetPath(data, command.Path, command.Data, &SetPathOpts{CombineFn: CombineFn_ArrayAppend, Budget: budget})
+func getCommandType(command map[string]any) string {
+	typeVal, ok := command["type"]
+	if !ok {
+		return ""
+	}
+	typeStr, ok := typeVal.(string)
+	if !ok {
+		return ""
+	}
+	return typeStr
+}
+
+func getCommandPath(command map[string]any) []any {
+	pathVal, ok := command["path"]
+	if !ok {
+		return nil
+	}
+	path, ok := pathVal.([]any)
+	if !ok {
+		return nil
+	}
+	return path
+}
+
+func ApplyCommand(data any, command any, budget int) (any, error) {
+	mapVal, ok := command.(map[string]any)
+	if !ok {
+		return nil, fmt.Errorf("ApplyCommand: expected map, but got %T", command)
+	}
+	commandType := getCommandType(mapVal)
+	if commandType == "" {
+		return nil, fmt.Errorf("ApplyCommand: missing type field")
+	}
+	switch commandType {
+	case SetCommandStr:
+		path := getCommandPath(mapVal)
+		return SetPath(data, path, mapVal["data"], &SetPathOpts{Budget: budget})
+	case DelCommandStr:
+		path := getCommandPath(mapVal)
+		return SetPath(data, path, nil, &SetPathOpts{Remove: true, Budget: budget})
+	case AppendCommandStr:
+		path := getCommandPath(mapVal)
+		return SetPath(data, path, mapVal["data"], &SetPathOpts{CombineFn: CombineFn_ArrayAppend, Budget: budget})
 	default:
-		return nil, fmt.Errorf("unknown command type %T", command)
+		return nil, fmt.Errorf("ApplyCommand: unknown command type %q", commandType)
 	}
 }