From 625d8f2afe93bac77715225b3574a5e8cf7fb045 Mon Sep 17 00:00:00 2001
From: Dayuan Jiang <34411969+DayuanJiang@users.noreply.github.com>
Date: Mon, 5 Jan 2026 23:09:09 +0900
Subject: [PATCH] fix: use OpenAI provider for Doubao multimodal models (#519)

DeepSeek provider was not properly formatting image content for Doubao's
API. Now uses OpenAI provider for Doubao models (multimodal support),
while keeping DeepSeek provider for DeepSeek/Kimi models on the platform.
---
 app/api/validate-model/route.ts | 27 ++++++++++++++++++++-------
 lib/ai-providers.ts             | 23 ++++++++++++++++++-----
 2 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/app/api/validate-model/route.ts b/app/api/validate-model/route.ts
index 2185ae8..b00e734 100644
--- a/app/api/validate-model/route.ts
+++ b/app/api/validate-model/route.ts
@@ -251,13 +251,26 @@ export async function POST(req: Request) {
             }
 
             case "doubao": {
-                // ByteDance Doubao uses DeepSeek-compatible API
-                const doubao = createDeepSeek({
-                    apiKey,
-                    baseURL:
-                        baseUrl || "https://ark.cn-beijing.volces.com/api/v3",
-                })
-                model = doubao(modelId)
+                // ByteDance Doubao: use DeepSeek for DeepSeek/Kimi models, OpenAI for others
+                const doubaoBaseUrl =
+                    baseUrl || "https://ark.cn-beijing.volces.com/api/v3"
+                const lowerModelId = modelId.toLowerCase()
+                if (
+                    lowerModelId.includes("deepseek") ||
+                    lowerModelId.includes("kimi")
+                ) {
+                    const doubao = createDeepSeek({
+                        apiKey,
+                        baseURL: doubaoBaseUrl,
+                    })
+                    model = doubao(modelId)
+                } else {
+                    const doubao = createOpenAI({
+                        apiKey,
+                        baseURL: doubaoBaseUrl,
+                    })
+                    model = doubao.chat(modelId)
+                }
                 break
             }
 
diff --git a/lib/ai-providers.ts b/lib/ai-providers.ts
index 9f30db2..c4c8574 100644
--- a/lib/ai-providers.ts
+++ b/lib/ai-providers.ts
@@ -871,11 +871,24 @@ export function getAIModel(overrides?: ClientOverrides): ModelConfig {
                 overrides?.baseUrl ||
                 process.env.DOUBAO_BASE_URL ||
                 "https://ark.cn-beijing.volces.com/api/v3"
-            const doubaoProvider = createDeepSeek({
-                apiKey,
-                baseURL,
-            })
-            model = doubaoProvider(modelId)
+            const lowerModelId = modelId.toLowerCase()
+            // Use DeepSeek provider for DeepSeek/Kimi models, OpenAI for others (multimodal support)
+            if (
+                lowerModelId.includes("deepseek") ||
+                lowerModelId.includes("kimi")
+            ) {
+                const doubaoProvider = createDeepSeek({
+                    apiKey,
+                    baseURL,
+                })
+                model = doubaoProvider(modelId)
+            } else {
+                const doubaoProvider = createOpenAI({
+                    apiKey,
+                    baseURL,
+                })
+                model = doubaoProvider.chat(modelId)
+            }
             break
         }