feat(providers): add LongCat model provider support (#1317)

* feat(providers): add LongCat model provider support

Add LongCat as an OpenAI-compatible provider with base URL
https://api.longcat.chat/openai and default model LongCat-Flash-Thinking.
Includes provider config, migration, factory routing, example config,
tests, and README entries for all 6 locales.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(providers): address LongCat review feedback

- Add dedicated factory routing test for LongCat provider
- Add longcat to DefaultAPIBase test coverage
- Set default api_base in example config providers section

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* test(providers): add ResolveProviderSelection tests for LongCat

Add two test cases to TestResolveProviderSelection:
- Explicit provider selection with api_base default and proxy wiring
- Fallback inference from model name with api_base default

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.fr.md

@@ -980,6 +980,7 @@ Cette conception permet également le **support multi-agent** avec une sélectio
 | **Cerebras** | `cerebras/` | `https://api.cerebras.ai/v1` | OpenAI | [Obtenir Clé](https://cerebras.ai) |
 | **Volcengine** | `volcengine/` | `https://ark.cn-beijing.volces.com/api/v3` | OpenAI | [Obtenir Clé](https://console.volcengine.com) |
 | **ShengsuanYun** | `shengsuanyun/` | `https://router.shengsuanyun.com/api/v1` | OpenAI | - |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [Obtenir une clé](https://longcat.chat/platform)                 |
 | **Antigravity** | `antigravity/` | Google Cloud | Custom | OAuth uniquement |
 | **GitHub Copilot** | `github-copilot/` | `localhost:4321` | gRPC | - |
 

README.ja.md

@@ -921,6 +921,7 @@ HEARTBEAT_OK 応答         ユーザーが直接結果を受け取る
 | **Cerebras** | `cerebras/` | `https://api.cerebras.ai/v1` | OpenAI | [キーを取得](https://cerebras.ai) |
 | **Volcengine** | `volcengine/` | `https://ark.cn-beijing.volces.com/api/v3` | OpenAI | [キーを取得](https://console.volcengine.com) |
 | **ShengsuanYun** | `shengsuanyun/` | `https://router.shengsuanyun.com/api/v1` | OpenAI | - |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [キーを取得](https://longcat.chat/platform)                      |
 | **Antigravity** | `antigravity/` | Google Cloud | カスタム | OAuthのみ |
 | **GitHub Copilot** | `github-copilot/` | `localhost:4321` | gRPC | - |
 

README.md

@@ -1034,6 +1034,7 @@ This design also enables **multi-agent support** with flexible provider selectio
 | **火山引擎**        | `volcengine/`     | `https://ark.cn-beijing.volces.com/api/v3`          | OpenAI    | [Get Key](https://console.volcengine.com)                        |
 | **神算云**          | `shengsuanyun/`   | `https://router.shengsuanyun.com/api/v1`            | OpenAI    | -                                                                |
 | **Vivgrid**         | `vivgrid/`        | `https://api.vivgrid.com/v1`                        | OpenAI    | [Get Key](https://vivgrid.com)                                   |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [Get Key](https://longcat.chat/platform)                         |
 | **Antigravity**     | `antigravity/`    | Google Cloud                                        | Custom    | OAuth only                                                       |
 | **GitHub Copilot**  | `github-copilot/` | `localhost:4321`                                    | gRPC      | -                                                                |
 
@@ -1504,3 +1505,4 @@ This happens when another instance of the bot is running. Make sure only one `pi
 | **SearXNG**      | Unlimited (self-hosted)  | Privacy-focused metasearch (70+ engines) |
 | **Groq**         | Free tier available      | Fast inference (Llama, Mixtral)       |
 | **Cerebras**     | Free tier available      | Fast inference (Llama, Qwen, etc.)    |
+| **LongCat**      | Up to 5M tokens/day      | Fast inference (free tier)            |

README.pt-br.md

@@ -976,6 +976,7 @@ Este design também possibilita o **suporte multi-agent** com seleção flexíve
 | **Cerebras** | `cerebras/` | `https://api.cerebras.ai/v1` | OpenAI | [Obter Chave](https://cerebras.ai) |
 | **Volcengine** | `volcengine/` | `https://ark.cn-beijing.volces.com/api/v3` | OpenAI | [Obter Chave](https://console.volcengine.com) |
 | **ShengsuanYun** | `shengsuanyun/` | `https://router.shengsuanyun.com/api/v1` | OpenAI | - |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [Obter Chave](https://longcat.chat/platform)                     |
 | **Antigravity** | `antigravity/` | Google Cloud | Custom | Apenas OAuth |
 | **GitHub Copilot** | `github-copilot/` | `localhost:4321` | gRPC | - |
 

README.vi.md

@@ -945,6 +945,7 @@ Thiết kế này cũng cho phép **hỗ trợ đa tác nhân** với lựa ch
 | **Cerebras** | `cerebras/` | `https://api.cerebras.ai/v1` | OpenAI | [Lấy Khóa](https://cerebras.ai) |
 | **Volcengine** | `volcengine/` | `https://ark.cn-beijing.volces.com/api/v3` | OpenAI | [Lấy Khóa](https://console.volcengine.com) |
 | **ShengsuanYun** | `shengsuanyun/` | `https://router.shengsuanyun.com/api/v1` | OpenAI | - |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [Lấy Key](https://longcat.chat/platform)                        |
 | **Antigravity** | `antigravity/` | Google Cloud | Tùy chỉnh | Chỉ OAuth |
 | **GitHub Copilot** | `github-copilot/` | `localhost:4321` | gRPC | - |
 

README.zh.md

@@ -517,6 +517,7 @@ Agent 读取 HEARTBEAT.md
 | **Cerebras**        | `cerebras/`       | `https://api.cerebras.ai/v1`                        | OpenAI    | [获取密钥](https://cerebras.ai)                                   |
 | **火山引擎**        | `volcengine/`     | `https://ark.cn-beijing.volces.com/api/v3`          | OpenAI    | [获取密钥](https://console.volcengine.com)                        |
 | **神算云**          | `shengsuanyun/`   | `https://router.shengsuanyun.com/api/v1`            | OpenAI    | -                                                                 |
+| **LongCat**         | `longcat/`        | `https://api.longcat.chat/openai`                   | OpenAI    | [获取密钥](https://longcat.chat/platform)                        |
 | **Antigravity**     | `antigravity/`    | Google Cloud                                        | 自定义    | 仅 OAuth                                                          |
 | **GitHub Copilot**  | `github-copilot/` | `localhost:4321`                                    | gRPC      | -                                                                 |
 
@@ -879,3 +880,4 @@ Discord: [https://discord.gg/V4sAZ9XWpN](https://discord.gg/V4sAZ9XWpN)
 | **Brave Search** | 2000 次查询/月 | 网络搜索功能 |
 | **Tavily** | 1000 次查询/月 | AI Agent 搜索优化 |
 | **Groq** | 提供免费层级 | 极速推理 (Llama, Mixtral) |
+| **LongCat** | 最多 5M tokens/天 | 推理速度快 (免费额度) |

config/config.example.json

@@ -35,6 +35,11 @@
       "model": "deepseek/deepseek-chat",
       "api_key": "sk-your-deepseek-key"
     },
+    {
+      "model_name": "longcat",
+      "model": "longcat/LongCat-Flash-Thinking",
+      "api_key": "your-longcat-api-key"
+    },
     {
       "model_name": "loadbalanced-gpt4",
       "model": "openai/gpt-5.2",
@@ -274,6 +279,10 @@
     "avian": {
       "api_key": "",
       "api_base": "https://api.avian.io/v1"
+    },
+    "longcat": {
+      "api_key": "",
+      "api_base": "https://api.longcat.chat/openai"
     }
   },
   "tools": {

pkg/config/config.go

@@ -527,6 +527,7 @@ type ProvidersConfig struct {
 	Mistral       ProviderConfig       `json:"mistral"`
 	Avian         ProviderConfig       `json:"avian"`
 	Minimax       ProviderConfig       `json:"minimax"`
+	LongCat       ProviderConfig       `json:"longcat"`
 }
 
 // IsEmpty checks if all provider configs are empty (no API keys or API bases set)
@@ -553,7 +554,8 @@ func (p ProvidersConfig) IsEmpty() bool {
 		p.Qwen.APIKey == "" && p.Qwen.APIBase == "" &&
 		p.Mistral.APIKey == "" && p.Mistral.APIBase == "" &&
 		p.Avian.APIKey == "" && p.Avian.APIBase == "" &&
-		p.Minimax.APIKey == "" && p.Minimax.APIBase == ""
+		p.Minimax.APIKey == "" && p.Minimax.APIBase == "" &&
+		p.LongCat.APIKey == "" && p.LongCat.APIBase == ""
 }
 
 // MarshalJSON implements custom JSON marshaling for ProvidersConfig

pkg/config/defaults.go

@@ -355,6 +355,14 @@ func DefaultConfig() *Config {
 				APIKey:    "",
 			},
 
+			// LongCat - https://longcat.chat/platform
+			{
+				ModelName: "LongCat-Flash-Thinking",
+				Model:     "longcat/LongCat-Flash-Thinking",
+				APIBase:   "https://api.longcat.chat/openai",
+				APIKey:    "",
+			},
+
 			// VLLM (local) - http://localhost:8000
 			{
 				ModelName: "local-model",

pkg/config/migration.go

@@ -407,6 +407,23 @@ func ConvertProvidersToModelList(cfg *Config) []ModelConfig {
 				}, true
 			},
 		},
+		{
+			providerNames: []string{"longcat"},
+			protocol:      "longcat",
+			buildConfig: func(p ProvidersConfig) (ModelConfig, bool) {
+				if p.LongCat.APIKey == "" && p.LongCat.APIBase == "" {
+					return ModelConfig{}, false
+				}
+				return ModelConfig{
+					ModelName:      "longcat",
+					Model:          "longcat/LongCat-Flash-Thinking",
+					APIKey:         p.LongCat.APIKey,
+					APIBase:        p.LongCat.APIBase,
+					Proxy:          p.LongCat.Proxy,
+					RequestTimeout: p.LongCat.RequestTimeout,
+				}, true
+			},
+		},
 	}
 
 	// Process each provider migration

pkg/config/migration_test.go

@@ -162,14 +162,15 @@ func TestConvertProvidersToModelList_AllProviders(t *testing.T) {
 			Qwen:          ProviderConfig{APIKey: "key17"},
 			Mistral:       ProviderConfig{APIKey: "key18"},
 			Avian:         ProviderConfig{APIKey: "key19"},
+			LongCat:       ProviderConfig{APIKey: "key-longcat"},
 		},
 	}
 
 	result := ConvertProvidersToModelList(cfg)
 
-	// All 21 providers should be converted
+	// All 22 providers should be converted
-	if len(result) != 21 {
+	if len(result) != 22 {
-		t.Errorf("len(result) = %d, want 21", len(result))
+		t.Errorf("len(result) = %d, want 22", len(result))
 	}
 }
 

pkg/providers/factory.go

@@ -221,6 +221,15 @@ func resolveProviderSelection(cfg *config.Config) (providerSelection, error) {
 					sel.apiBase = "https://api.minimaxi.com/v1"
 				}
 			}
+		case "longcat":
+			if cfg.Providers.LongCat.APIKey != "" {
+				sel.apiKey = cfg.Providers.LongCat.APIKey
+				sel.apiBase = cfg.Providers.LongCat.APIBase
+				sel.proxy = cfg.Providers.LongCat.Proxy
+				if sel.apiBase == "" {
+					sel.apiBase = "https://api.longcat.chat/openai"
+				}
+			}
 		case "github_copilot", "copilot":
 			sel.providerType = providerTypeGitHubCopilot
 			if cfg.Providers.GitHubCopilot.APIBase != "" {
@@ -352,6 +361,13 @@ func resolveProviderSelection(cfg *config.Config) (providerSelection, error) {
 			if sel.apiBase == "" {
 				sel.apiBase = "https://api.avian.io/v1"
 			}
+		case (strings.Contains(lowerModel, "longcat") || strings.HasPrefix(model, "longcat/")) && cfg.Providers.LongCat.APIKey != "":
+			sel.apiKey = cfg.Providers.LongCat.APIKey
+			sel.apiBase = cfg.Providers.LongCat.APIBase
+			sel.proxy = cfg.Providers.LongCat.Proxy
+			if sel.apiBase == "" {
+				sel.apiBase = "https://api.longcat.chat/openai"
+			}
 		case cfg.Providers.VLLM.APIBase != "":
 			sel.apiKey = cfg.Providers.VLLM.APIKey
 			sel.apiBase = cfg.Providers.VLLM.APIBase

pkg/providers/factory_provider.go

@@ -95,7 +95,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 	case "litellm", "openrouter", "groq", "zhipu", "gemini", "nvidia",
 		"ollama", "moonshot", "shengsuanyun", "deepseek", "cerebras",
 		"vivgrid", "volcengine", "vllm", "qwen", "mistral", "avian",
-		"minimax":
+		"minimax", "longcat":
 		// All other OpenAI-compatible HTTP providers
 		if cfg.APIKey == "" && cfg.APIBase == "" {
 			return nil, "", fmt.Errorf("api_key or api_base is required for HTTP-based protocol %q", protocol)
@@ -215,6 +215,8 @@ func getDefaultAPIBase(protocol string) string {
 		return "https://api.avian.io/v1"
 	case "minimax":
 		return "https://api.minimaxi.com/v1"
+	case "longcat":
+		return "https://api.longcat.chat/openai"
 	default:
 		return ""
 	}

pkg/providers/factory_provider_test.go

@@ -113,6 +113,7 @@ func TestCreateProviderFromConfig_DefaultAPIBase(t *testing.T) {
 		{"vllm", "vllm"},
 		{"deepseek", "deepseek"},
 		{"ollama", "ollama"},
+		{"longcat", "longcat"},
 	}
 
 	for _, tt := range tests {
@@ -162,6 +163,29 @@ func TestCreateProviderFromConfig_LiteLLM(t *testing.T) {
 	}
 }
 
+func TestCreateProviderFromConfig_LongCat(t *testing.T) {
+	cfg := &config.ModelConfig{
+		ModelName: "test-longcat",
+		Model:     "longcat/LongCat-Flash-Thinking",
+		APIKey:    "test-key",
+		APIBase:   "https://api.longcat.chat/openai",
+	}
+
+	provider, modelID, err := CreateProviderFromConfig(cfg)
+	if err != nil {
+		t.Fatalf("CreateProviderFromConfig() error = %v", err)
+	}
+	if provider == nil {
+		t.Fatal("CreateProviderFromConfig() returned nil provider")
+	}
+	if modelID != "LongCat-Flash-Thinking" {
+		t.Errorf("modelID = %q, want %q", modelID, "LongCat-Flash-Thinking")
+	}
+	if _, ok := provider.(*HTTPProvider); !ok {
+		t.Fatalf("expected *HTTPProvider, got %T", provider)
+	}
+}
+
 func TestCreateProviderFromConfig_Anthropic(t *testing.T) {
 	cfg := &config.ModelConfig{
 		ModelName: "test-anthropic",

pkg/providers/factory_test.go

@@ -178,6 +178,26 @@ func TestResolveProviderSelection(t *testing.T) {
 			wantAPIBase: "https://api.moonshot.cn/v1",
 			wantProxy:   "http://127.0.0.1:7890",
 		},
+		{
+			name: "explicit longcat provider uses defaults",
+			setup: func(cfg *config.Config) {
+				cfg.Agents.Defaults.Provider = "longcat"
+				cfg.Providers.LongCat.APIKey = "longcat-key"
+				cfg.Providers.LongCat.Proxy = "http://127.0.0.1:7890"
+			},
+			wantType:    providerTypeHTTPCompat,
+			wantAPIBase: "https://api.longcat.chat/openai",
+			wantProxy:   "http://127.0.0.1:7890",
+		},
+		{
+			name: "longcat model fallback uses longcat base default",
+			setup: func(cfg *config.Config) {
+				cfg.Agents.Defaults.Model = "longcat/LongCat-Flash-Thinking"
+				cfg.Providers.LongCat.APIKey = "longcat-key"
+			},
+			wantType:    providerTypeHTTPCompat,
+			wantAPIBase: "https://api.longcat.chat/openai",
+		},
 		{
 			name: "missing keys returns model config error",
 			setup: func(cfg *config.Config) {