refactor: use Tommy TOML library directly for config file manipulation (#328)

Before discovering the Tommy library I tried to parse TOML files directly. Some of the methods lingered from that time, which were messing up configuration on Windows.

Now we use Tommy more, it should work. Also consolidated some code with fresh eyes

Closes #311

Author: msanatan

MCPForUnity/Editor/Helpers/CodexConfigHelper.cs

@@ -2,10 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Text;
-using System.Text.RegularExpressions;
 using MCPForUnity.External.Tommy;
-using Newtonsoft.Json;
 
 namespace MCPForUnity.Editor.Helpers
 {
@@ -42,108 +39,107 @@ public static bool IsCodexConfigured(string pythonDir)
 
         public static string BuildCodexServerBlock(string uvPath, string serverSrc)
         {
-            string argsArray = FormatTomlStringArray(new[] { "run", "--directory", serverSrc, "server.py" });
-            return $"[mcp_servers.unityMCP]{Environment.NewLine}" +
-                   $"command = \"{EscapeTomlString(uvPath)}\"{Environment.NewLine}" +
-                   $"args = {argsArray}";
+            var table = new TomlTable();
+            var mcpServers = new TomlTable();
+
+            mcpServers["unityMCP"] = CreateUnityMcpTable(uvPath, serverSrc);
+            table["mcp_servers"] = mcpServers;
+
+            using var writer = new StringWriter();
+            table.WriteTo(writer);
+            return writer.ToString();
         }
 
-        public static string UpsertCodexServerBlock(string existingToml, string newBlock)
+        public static string UpsertCodexServerBlock(string existingToml, string uvPath, string serverSrc)
         {
-            if (string.IsNullOrWhiteSpace(existingToml))
+            // Parse existing TOML or create new root table
+            var root = TryParseToml(existingToml) ?? new TomlTable();
+
+            // Ensure mcp_servers table exists
+            if (!root.TryGetNode("mcp_servers", out var mcpServersNode) || !(mcpServersNode is TomlTable))
             {
-                return newBlock.TrimEnd() + Environment.NewLine;
+                root["mcp_servers"] = new TomlTable();
             }
+            var mcpServers = root["mcp_servers"] as TomlTable;
 
-            StringBuilder sb = new StringBuilder();
-            using StringReader reader = new StringReader(existingToml);
-            string line;
-            bool inTarget = false;
-            bool replaced = false;
-            while ((line = reader.ReadLine()) != null)
-            {
-                string trimmed = line.Trim();
-                bool isSection = trimmed.StartsWith("[") && trimmed.EndsWith("]") && !trimmed.StartsWith("[[");
-                if (isSection)
-                {
-                    bool isTarget = string.Equals(trimmed, "[mcp_servers.unityMCP]", StringComparison.OrdinalIgnoreCase);
-                    if (isTarget)
-                    {
-                        if (!replaced)
-                        {
-                            if (sb.Length > 0 && sb[^1] != '\n') sb.AppendLine();
-                            sb.AppendLine(newBlock.TrimEnd());
-                            replaced = true;
-                        }
-                        inTarget = true;
-                        continue;
-                    }
+            // Create or update unityMCP table
+            mcpServers["unityMCP"] = CreateUnityMcpTable(uvPath, serverSrc);
 
-                    if (inTarget)
-                    {
-                        inTarget = false;
-                    }
-                }
+            // Serialize back to TOML
+            using var writer = new StringWriter();
+            root.WriteTo(writer);
+            return writer.ToString();
+        }
 
-                if (inTarget)
-                {
-                    continue;
-                }
+        public static bool TryParseCodexServer(string toml, out string command, out string[] args)
+        {
+            command = null;
+            args = null;
 
-                sb.AppendLine(line);
+            var root = TryParseToml(toml);
+            if (root == null) return false;
+
+            if (!TryGetTable(root, "mcp_servers", out var servers)
+                && !TryGetTable(root, "mcpServers", out servers))
+            {
+                return false;
             }
 
-            if (!replaced)
+            if (!TryGetTable(servers, "unityMCP", out var unity))
             {
-                if (sb.Length > 0 && sb[^1] != '\n') sb.AppendLine();
-                sb.AppendLine(newBlock.TrimEnd());
+                return false;
             }
 
-            return sb.ToString().TrimEnd() + Environment.NewLine;
+            command = GetTomlString(unity, "command");
+            args = GetTomlStringArray(unity, "args");
+
+            return !string.IsNullOrEmpty(command) && args != null;
         }
 
-        public static bool TryParseCodexServer(string toml, out string command, out string[] args)
+        /// <summary>
+        /// Safely parses TOML string, returning null on failure
+        /// </summary>
+        private static TomlTable TryParseToml(string toml)
         {
-            command = null;
-            args = null;
-            if (string.IsNullOrWhiteSpace(toml)) return false;
+            if (string.IsNullOrWhiteSpace(toml)) return null;
 
             try
             {
                 using var reader = new StringReader(toml);
-                TomlTable root = TOML.Parse(reader);
-                if (root == null) return false;
-
-                if (!TryGetTable(root, "mcp_servers", out var servers)
-                    && !TryGetTable(root, "mcpServers", out servers))
-                {
-                    return false;
-                }
-
-                if (!TryGetTable(servers, "unityMCP", out var unity))
-                {
-                    return false;
-                }
-
-                command = GetTomlString(unity, "command");
-                args = GetTomlStringArray(unity, "args");
-
-                return !string.IsNullOrEmpty(command) && args != null;
+                return TOML.Parse(reader);
             }
             catch (TomlParseException)
             {
-                return false;
+                return null;
             }
             catch (TomlSyntaxException)
             {
-                return false;
+                return null;
             }
             catch (FormatException)
             {
-                return false;
+                return null;
             }
         }
 
+        /// <summary>
+        /// Creates a TomlTable for the unityMCP server configuration
+        /// </summary>
+        private static TomlTable CreateUnityMcpTable(string uvPath, string serverSrc)
+        {
+            var unityMCP = new TomlTable();
+            unityMCP["command"] = new TomlString { Value = uvPath };
+
+            var argsArray = new TomlArray();
+            argsArray.Add(new TomlString { Value = "run" });
+            argsArray.Add(new TomlString { Value = "--directory" });
+            argsArray.Add(new TomlString { Value = serverSrc });
+            argsArray.Add(new TomlString { Value = "server.py" });
+            unityMCP["args"] = argsArray;
+
+            return unityMCP;
+        }
+
         private static bool TryGetTable(TomlTable parent, string key, out TomlTable table)
         {
             table = null;
@@ -211,33 +207,5 @@ private static string[] GetTomlStringArray(TomlTable table, string key)
 
             return null;
         }
-
-        private static string FormatTomlStringArray(IEnumerable<string> values)
-        {
-            if (values == null) return "[]";
-            StringBuilder sb = new StringBuilder();
-            sb.Append('[');
-            bool first = true;
-            foreach (string value in values)
-            {
-                if (!first)
-                {
-                    sb.Append(", ");
-                }
-                sb.Append('"').Append(EscapeTomlString(value ?? string.Empty)).Append('"');
-                first = false;
-            }
-            sb.Append(']');
-            return sb.ToString();
-        }
-
-        private static string EscapeTomlString(string value)
-        {
-            if (string.IsNullOrEmpty(value)) return string.Empty;
-            return value
-                .Replace("\\", "\\\\")
-                .Replace("\"", "\\\"");
-        }
-
     }
 }

MCPForUnity/Editor/Helpers/McpConfigurationHelper.cs

@@ -205,8 +205,7 @@ public static string ConfigureCodexClient(string pythonDir, string configPath, M
                 return "Configured successfully";
             }
 
-            string codexBlock = CodexConfigHelper.BuildCodexServerBlock(uvPath, serverSrc);
-            string updatedToml = CodexConfigHelper.UpsertCodexServerBlock(existingToml, codexBlock);
+            string updatedToml = CodexConfigHelper.UpsertCodexServerBlock(existingToml, uvPath, serverSrc);
 
             McpConfigFileHelper.WriteAtomicFile(configPath, updatedToml);