feat: Add OpenCode (opencode.ai) client configurator (#608)

* feat: Add OpenCode (opencode.ai) client configurator

Add support for the OpenCode CLI client with automatic configuration.

- Create OpenCodeConfigurator implementing IClientConfigurator
- Configure via ~/.config/opencode/opencode.json (XDG standard path)
- Use McpConfigurationHelper for atomic file writes and directory creation
- Support both new config creation and merging with existing config

Co-Authored-By: akshay-kiddopia <akshay@kiddopia.com>
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: Address code review feedback for OpenCodeConfigurator

- Add TryLoadConfig() helper to consolidate file read/parse logic
- Handle JsonException separately (log warning, return empty object to overwrite)
- Wrap Configure() in try/catch to prevent crashes, set McpStatus.Error on failure
- Respect XDG_CONFIG_HOME environment variable per XDG Base Directory spec

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: akshay-kiddopia <akshay@kiddopia.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs

@@ -0,0 +1,156 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using MCPForUnity.Editor.Helpers;
+using MCPForUnity.Editor.Models;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace MCPForUnity.Editor.Clients.Configurators
+{
+    /// <summary>
+    /// Configurator for OpenCode (opencode.ai) - a Go-based terminal AI coding assistant.
+    /// OpenCode uses ~/.config/opencode/opencode.json with a custom "mcp" format.
+    /// </summary>
+    public class OpenCodeConfigurator : McpClientConfiguratorBase
+    {
+        private const string ServerName = "unityMCP";
+        private const string SchemaUrl = "https://opencode.ai/config.json";
+
+        public OpenCodeConfigurator() : base(new McpClient
+        {
+            name = "OpenCode",
+            windowsConfigPath = BuildConfigPath(),
+            macConfigPath = BuildConfigPath(),
+            linuxConfigPath = BuildConfigPath()
+        })
+        { }
+
+        private static string BuildConfigPath()
+        {
+            string xdgConfigHome = Environment.GetEnvironmentVariable("XDG_CONFIG_HOME");
+            string configBase = !string.IsNullOrEmpty(xdgConfigHome)
+                ? xdgConfigHome
+                : Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".config");
+            return Path.Combine(configBase, "opencode", "opencode.json");
+        }
+
+        public override string GetConfigPath() => CurrentOsPath();
+
+        /// <summary>
+        /// Attempts to load and parse the config file.
+        /// Returns null if file doesn't exist.
+        /// Returns empty JObject if file exists but contains malformed JSON (logs warning).
+        /// Throws on I/O errors (permission denied, etc.).
+        /// </summary>
+        private JObject TryLoadConfig(string path)
+        {
+            if (!File.Exists(path))
+                return null;
+
+            string content = File.ReadAllText(path);
+            try
+            {
+                return JsonConvert.DeserializeObject<JObject>(content) ?? new JObject();
+            }
+            catch (JsonException)
+            {
+                // Malformed JSON - return empty object so caller can overwrite with valid config
+                UnityEngine.Debug.LogWarning($"[OpenCodeConfigurator] Malformed JSON in {path}, will overwrite with valid config");
+                return new JObject();
+            }
+        }
+
+        public override McpStatus CheckStatus(bool attemptAutoRewrite = true)
+        {
+            try
+            {
+                string path = GetConfigPath();
+                var config = TryLoadConfig(path);
+
+                if (config == null)
+                {
+                    client.SetStatus(McpStatus.NotConfigured);
+                    return client.status;
+                }
+
+                var unityMcp = config["mcp"]?[ServerName] as JObject;
+
+                if (unityMcp == null)
+                {
+                    client.SetStatus(McpStatus.NotConfigured);
+                    return client.status;
+                }
+
+                string configuredUrl = unityMcp["url"]?.ToString();
+                string expectedUrl = HttpEndpointUtility.GetMcpRpcUrl();
+
+                if (UrlsEqual(configuredUrl, expectedUrl))
+                {
+                    client.SetStatus(McpStatus.Configured);
+                }
+                else if (attemptAutoRewrite)
+                {
+                    Configure();
+                }
+                else
+                {
+                    client.SetStatus(McpStatus.IncorrectPath);
+                }
+            }
+            catch (Exception ex)
+            {
+                client.SetStatus(McpStatus.Error, ex.Message);
+            }
+
+            return client.status;
+        }
+
+        public override void Configure()
+        {
+            try
+            {
+                string path = GetConfigPath();
+                McpConfigurationHelper.EnsureConfigDirectoryExists(path);
+
+                var config = TryLoadConfig(path) ?? new JObject { ["$schema"] = SchemaUrl };
+
+                var mcpSection = config["mcp"] as JObject ?? new JObject();
+                config["mcp"] = mcpSection;
+
+                mcpSection[ServerName] = BuildServerEntry();
+
+                McpConfigurationHelper.WriteAtomicFile(path, JsonConvert.SerializeObject(config, Formatting.Indented));
+                client.SetStatus(McpStatus.Configured);
+            }
+            catch (Exception ex)
+            {
+                client.SetStatus(McpStatus.Error, ex.Message);
+            }
+        }
+
+        public override string GetManualSnippet()
+        {
+            var snippet = new JObject
+            {
+                ["mcp"] = new JObject { [ServerName] = BuildServerEntry() }
+            };
+            return JsonConvert.SerializeObject(snippet, Formatting.Indented);
+        }
+
+        public override IList<string> GetInstallationSteps() => new List<string>
+        {
+            "Install OpenCode (https://opencode.ai)",
+            "Click Configure to add Unity MCP to ~/.config/opencode/opencode.json",
+            "Restart OpenCode",
+            "The Unity MCP server should be detected automatically"
+        };
+
+        private static JObject BuildServerEntry() => new JObject
+        {
+            ["type"] = "remote",
+            ["url"] = HttpEndpointUtility.GetMcpRpcUrl(),
+            ["enabled"] = true
+        };
+    }
+}

MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 489f99ffb7e6743e88e3203552c8b37b