feat(asset-gen): register MiniMax as a 2D image provider

Add MiniMaxImageAdapter (IImageProviderAdapter) for the synchronous
/v1/image_generation endpoint: text->image and image->image (subject_reference)
with a URL or inline base64 data URI. Register minimax in the image provider
chain, catalog (image-01 default, image-01-live), secure-key provider list,
settings panel, CLI/server tool descriptions, and the manual-verification doc.

Author: octo-patch

MCPForUnity/Editor/Security/SecureKeyStore/SecureKeyStoreConstants.cs

@@ -9,7 +9,7 @@ internal static class SecureKeyStoreConstants
         /// <summary>Known asset-generation provider ids (lowercase).</summary>
         internal static readonly string[] ProviderIds =
         {
-            "tripo", "meshy", "sketchfab", "fal", "openrouter"
+            "tripo", "meshy", "sketchfab", "fal", "openrouter", "minimax", "minimax"
         };
     }
 }

MCPForUnity/Editor/Services/AssetGen/AssetGenModelCatalog.cs

@@ -53,6 +53,10 @@ public static class AssetGenModelCatalog
             // Image — openrouter
             new ModelEntry { Id = OpenRouterAdapter.DefaultModel, Label = "Gemini 2.5 Flash Image", Provider = "openrouter", Kind = "image", UseCase = "General image" },
 
+            // Image — minimax (MiniMaxImageAdapter.DefaultModel is first => the default)
+            new ModelEntry { Id = MiniMaxImageAdapter.DefaultModel, Label = "MiniMax image-01", Provider = "minimax", Kind = "image", UseCase = "General image" },
+            new ModelEntry { Id = "image-01-live", Label = "MiniMax image-01-live", Provider = "minimax", Kind = "image", UseCase = "Live image" },
+
             // 3D — tripo / meshy (defaults reference the adapter constants)
             new ModelEntry { Id = TripoAdapter.ModelVersion, Label = "Tripo v3.1", Provider = "tripo", Kind = "model", UseCase = "Text / image -> 3D" },
             new ModelEntry { Id = "P1-20260311", Label = "Tripo P1 (premium)", Provider = "tripo", Kind = "model", UseCase = "Premium 3D" },

MCPForUnity/Editor/Services/AssetGen/Providers/AssetGenProviders.cs

@@ -33,6 +33,8 @@ public static IImageProviderAdapter Image(string id)
                     return new FalAdapter();
                 case "openrouter":
                     return new OpenRouterAdapter();
+                case "minimax":
+                    return new MiniMaxImageAdapter();
                 default:
                     throw new NotSupportedException($"Unknown image provider '{id}'.");
             }
@@ -69,6 +71,7 @@ public static IReadOnlyList<ProviderInfo> List()
                 new ProviderInfo { Id = "sketchfab", Kind = "marketplace", Configured = IsConfigured("sketchfab"), Capabilities = new[] { "search", "import" } },
                 new ProviderInfo { Id = "fal", Kind = "image", Configured = IsConfigured("fal"), Capabilities = new[] { "text", "image" } },
                 new ProviderInfo { Id = "openrouter", Kind = "image", Configured = IsConfigured("openrouter"), Capabilities = new[] { "text", "image" } },
+                new ProviderInfo { Id = "minimax", Kind = "image", Configured = IsConfigured("minimax"), Capabilities = new[] { "text", "image" } },
                 // fal appears twice by design — once per kind (image + audio) — sharing the single "fal" key.
                 new ProviderInfo { Id = "fal", Kind = "audio", Configured = IsConfigured("fal"), Capabilities = new[] { "text", "music", "sfx" } },
             };

MCPForUnity/Editor/Services/AssetGen/Providers/MiniMaxImageAdapter.cs

@@ -0,0 +1,152 @@
+using System;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using MCPForUnity.Editor.Security;
+using MCPForUnity.Editor.Services.AssetGen.Http;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace MCPForUnity.Editor.Services.AssetGen.Providers
+{
+    /// <summary>
+    /// MiniMax 2D image provider via the synchronous <c>/v1/image_generation</c> endpoint. Text→image
+    /// submits a prompt; image→image attaches a <c>subject_reference</c> (a hosted URL or an inline
+    /// base64 data URI for a local image_path). The image is returned inline (base64) or as a URL the
+    /// job manager downloads, so all work happens in <see cref="SubmitAsync"/> and
+    /// <see cref="PollAsync"/> returns the captured result immediately. One adapter instance handles a
+    /// single job (the job manager captures it for submit+poll).
+    /// </summary>
+    public sealed class MiniMaxImageAdapter : IImageProviderAdapter
+    {
+        private const string Endpoint = "https://api.minimax.io/v1/image_generation";
+        private const string Host = "api.minimax.io";
+        // internal so the model catalog references it directly (single source of truth, drift-guarded).
+        internal const string DefaultModel = "image-01";
+
+        public string Id => "minimax";
+
+        private byte[] _inlineData;
+        private string _downloadUrl;
+        private string _error;
+
+        public async Task<string> SubmitAsync(ImageGenRequest req, string apiKey, IHttpTransport http, CancellationToken ct)
+        {
+            if (req == null) throw new ArgumentNullException(nameof(req));
+            if (http == null) throw new ArgumentNullException(nameof(http));
+
+            string model = string.IsNullOrEmpty(req.Model) ? DefaultModel : req.Model;
+
+            var body = new JObject
+            {
+                ["model"] = model,
+                ["prompt"] = req.Prompt ?? string.Empty
+            };
+
+            // image→image: attach the reference image as a subject_reference entry. image_file accepts
+            // a hosted URL or an inline base64 data URI (for a local image_path). Plain text→image
+            // sends prompt only.
+            bool image = string.Equals(req.Mode, "image", StringComparison.OrdinalIgnoreCase)
+                         && (!string.IsNullOrEmpty(req.ImageUrl) || !string.IsNullOrEmpty(req.ImagePath));
+            if (image)
+            {
+                string imageRef = !string.IsNullOrEmpty(req.ImageUrl) ? req.ImageUrl : LocalImage.ToDataUri(req.ImagePath);
+                body["subject_reference"] = new JArray(
+                    new JObject { ["type"] = "character", ["image_file"] = imageRef });
+            }
+
+            // Forward explicit output dimensions for text→image only; the provider accepts a
+            // {width,height} pair. (image→image derives size from the subject reference.)
+            if (!image && req.Width > 0 && req.Height > 0)
+            {
+                body["width"] = req.Width;
+                body["height"] = req.Height;
+            }
+
+            ProviderHttp.RequireHost(Endpoint, Host, apiKey, "minimax submit");
+
+            var spec = new HttpRequestSpec
+            {
+                Method = "POST",
+                Url = Endpoint,
+                ContentType = "application/json",
+                Body = Encoding.UTF8.GetBytes(body.ToString(Formatting.None))
+            };
+            spec.Headers["Authorization"] = "Bearer " + apiKey;
+
+            HttpResult res = await http.SendAsync(spec, ct);
+            JObject json = ParseOk(res, apiKey);
+
+            // Prefer a URL result (default response_format=url); fall back to inline base64.
+            string url = ExtractImageUrl(json);
+            if (!string.IsNullOrEmpty(url))
+            {
+                _downloadUrl = url;
+            }
+            else
+            {
+                string b64 = ExtractImageBase64(json);
+                if (!string.IsNullOrEmpty(b64))
+                {
+                    try { _inlineData = Convert.FromBase64String(b64); }
+                    catch { _error = "MiniMax returned an image payload that was not valid base64."; }
+                }
+                else
+                {
+                    _error = "MiniMax returned no image. The selected model may not support image output.";
+                }
+            }
+            return "ready";
+        }
+
+        public Task<ProviderPollResult> PollAsync(string providerJobId, string apiKey, IHttpTransport http, CancellationToken ct)
+        {
+            var result = new ProviderPollResult { Progress = 1f };
+            if (!string.IsNullOrEmpty(_error) || (_inlineData == null && string.IsNullOrEmpty(_downloadUrl)))
+            {
+                result.State = ProviderPollState.Failed;
+                result.Error = _error ?? "MiniMax produced no image.";
+            }
+            else
+            {
+                result.State = ProviderPollState.Succeeded;
+                result.InlineData = _inlineData;
+                result.DownloadUrl = _downloadUrl;
+            }
+            return Task.FromResult(result);
+        }
+
+        private static string ExtractImageUrl(JObject json)
+            => (json["data"]?["image_urls"] as JArray)?[0]?.ToString();
+
+        private static string ExtractImageBase64(JObject json)
+            => (json["data"]?["image_base64"] as JArray)?[0]?.ToString();
+
+        private static JObject ParseOk(HttpResult res, string apiKey)
+        {
+            string text = ProviderHttp.BodyText(res);
+
+            JObject json = null;
+            if (!string.IsNullOrEmpty(text))
+            {
+                try { json = JObject.Parse(text); } catch { /* non-JSON */ }
+            }
+
+            bool ok = res?.Ok == true;
+            // MiniMax signals failure with a non-zero base_resp.status_code even on HTTP 200.
+            int status = json?["base_resp"]?["status_code"]?.Type == JTokenType.Integer
+                ? (int)json["base_resp"]["status_code"]
+                : 0;
+            if (!ok || status != 0)
+            {
+                string detail = json?["base_resp"]?["status_msg"]?.ToString()
+                                ?? json?["error"]?["message"]?.ToString()
+                                ?? json?["error"]?.ToString()
+                                ?? ProviderHttp.Truncate(text);
+                throw new Exception(SecretRedactor.Scrub(
+                    $"MiniMax request failed (status={res?.Status}, base_resp.status_code={status}): {detail}", apiKey));
+            }
+            return json ?? new JObject();
+        }
+    }
+}

MCPForUnity/Editor/Services/AssetGen/Providers/MiniMaxImageAdapter.cs.meta

@@ -34,6 +34,7 @@ private static readonly (string Id, string Label)[] ImageProviders =
         {
             ("fal", "fal"),
             ("openrouter", "OpenRouter"),
+            ("minimax", "MiniMax"),
         };
 
         // UI Elements

MCPForUnity/Editor/Windows/Components/AssetGen/McpAssetGenSection.cs

@@ -146,7 +146,7 @@ def import_model_file(source_path, name, output_folder, target_size, animation_t
 
 
 @asset_gen.command("generate-image")
-@click.option("--provider", default=None, help="Provider id (fal, openrouter).")
+@click.option("--provider", default=None, help="Provider id (fal, openrouter, minimax).")
 @click.option("--mode", default=None, help="Generation mode: text or image.")
 @click.option("--prompt", default=None, help="Text prompt for text->image.")
 @click.option("--image-path", default=None, help="Source image path for image->image.")

Server/src/cli/commands/asset_gen.py

@@ -19,7 +19,7 @@
 @mcp_for_unity_tool(
     group="asset_gen",
     description=(
-        "Generate 2D images with AI providers (fal.ai, OpenRouter) and import them as "
+        "Generate 2D images with AI providers (fal.ai, OpenRouter, MiniMax) and import them as "
         "textures/sprites into the Unity project. Bring-your-own-key: provider keys live "
         "in the editor's secure store and never cross the bridge.\n\n"
         "ACTIONS:\n"
@@ -42,7 +42,7 @@ async def generate_image(
     action: Annotated[Literal["generate", "remove_background", "status", "cancel", "list_providers"],
                       "Action to perform."],
 
-    provider: Annotated[str, "Provider id (fal, openrouter)."] | None = None,
+    provider: Annotated[str, "Provider id (fal, openrouter, minimax)."] | None = None,
     mode: Annotated[str, "Generation mode: text or image."] | None = None,
     prompt: Annotated[str, "Text prompt for text->image."] | None = None,
     image_path: Annotated[str, "Path to a source image for image->image mode."] | None = None,

Server/src/services/tools/generate_image.py

@@ -25,6 +25,7 @@ public void SetUp()
             AssetGenJobManager.ResetForTests();
             Environment.SetEnvironmentVariable("MCPFORUNITY_FAL_API_KEY", null);
             Environment.SetEnvironmentVariable("MCPFORUNITY_OPENROUTER_API_KEY", null);
+            Environment.SetEnvironmentVariable("MCPFORUNITY_MINIMAX_API_KEY", null);
             _dir = Path.Combine(Path.GetTempPath(), "mcp_imghandler_" + Guid.NewGuid().ToString("N"));
             _store = new EncryptedFileKeyStore(_dir);
             SecureKeyStore.OverrideForTests(_store);
@@ -73,6 +74,20 @@ public void Generate_WithKey_ReturnsPendingJobId()
             Assert.IsFalse(string.IsNullOrEmpty((string)gen["data"]["job_id"]));
         }
 
+        [Test]
+        public void Generate_MiniMax_WithKey_ReturnsPendingJobId()
+        {
+            _store.Set("minimax", "mmkey");
+            AssetGenJobManager.TransportOverrideForTests = new FakeHttpTransport
+            {
+                Handler = spec => new HttpResult { Status = 200, IsSuccess = true,
+                    Text = "{\"data\":{\"image_urls\":[\"https://cdn.minimax.io/img/x.png\"]},\"base_resp\":{\"status_code\":0}}" }
+            };
+            JObject gen = Call(new JObject { ["action"] = "generate", ["provider"] = "minimax", ["mode"] = "text", ["prompt"] = "a cat" });
+            Assert.AreEqual("pending", (string)gen["_mcp_status"]);
+            Assert.IsFalse(string.IsNullOrEmpty((string)gen["data"]["job_id"]));
+        }
+
         [Test]
         public void Generate_NoKey_ReturnsError()
         {
@@ -136,6 +151,7 @@ public void ListProviders_ImageOnly()
             string s = resp.ToString();
             StringAssert.Contains("fal", s);
             StringAssert.Contains("openrouter", s);
+            StringAssert.Contains("minimax", s);
             StringAssert.DoesNotContain("tripo", s); // model providers excluded
         }