fix(provider): select Azure DeepSeek adapter

packages/core/src/plugin/provider/azure.ts

@@ -2,7 +2,17 @@ import { Effect } from "effect"
 import { define } from "../internal"
 import { ProviderV2 } from "../../provider"
 
-function selectLanguage(sdk: any, modelID: string, useChat: boolean) {
+function selectLanguage(
+  sdk: any,
+  model: { id: string; name: string; family?: string; api: { id: string } },
+  useChat: boolean,
+) {
+  const modelID = model.api.id
+  if (
+    sdk.deepseek &&
+    [modelID, model.id, model.name, model.family].some((value) => value?.toLowerCase().includes("deepseek"))
+  )
+    return sdk.deepseek(modelID)
   if (useChat && sdk.chat) return sdk.chat(modelID)
   if (sdk.responses) return sdk.responses(modelID)
   if (sdk.messages) return sdk.messages(modelID)
@@ -49,7 +59,7 @@ export const AzurePlugin = define({
     yield* ctx.aisdk.language(
       Effect.fn(function* (evt) {
         if (evt.model.providerID !== ProviderV2.ID.azure) return
-        evt.language = selectLanguage(evt.sdk, evt.model.api.id, Boolean(evt.options.useCompletionUrls))
+        evt.language = selectLanguage(evt.sdk, evt.model, Boolean(evt.options.useCompletionUrls))
       }),
     )
   }),
@@ -75,7 +85,7 @@ export const AzureCognitiveServicesPlugin = define({
     yield* ctx.aisdk.language(
       Effect.fn(function* (evt) {
         if (evt.model.providerID !== ProviderV2.ID.make("azure-cognitive-services")) return
-        evt.language = selectLanguage(evt.sdk, evt.model.api.id, Boolean(evt.options.useCompletionUrls))
+        evt.language = selectLanguage(evt.sdk, evt.model, Boolean(evt.options.useCompletionUrls))
       }),
     )
   }),

packages/core/test/plugin/provider-azure.test.ts

@@ -52,6 +52,7 @@ function fakeSelectorSdk(calls: string[]) {
     return { modelId: id, provider: method, specificationVersion: "v3" } as unknown as LanguageModelV3
   }
   return {
+    deepseek: make("deepseek"),
     responses: make("responses"),
     messages: make("messages"),
     chat: make("chat"),
@@ -197,6 +198,23 @@ describe("AzurePlugin", () => {
     }),
   )
 
+  it.effect("selects DeepSeek for named deployments", () =>
+    Effect.gen(function* () {
+      const aisdk = yield* AISDK.Service
+      const calls: string[] = []
+      yield* addPlugin()
+      yield* aisdk.runLanguage({
+        model: ModelV2.Info.make({
+          ...ModelV2.Info.empty(ProviderV2.ID.azure, ModelV2.ID.make("deepseek-v4-pro")),
+          api: { id: ModelV2.ID.make("production-deployment"), type: "aisdk", package: "test-provider" },
+        }),
+        sdk: fakeSelectorSdk(calls),
+        options: { useCompletionUrls: true },
+      })
+      expect(calls).toEqual(["deepseek:production-deployment"])
+    }),
+  )
+
   it.effect("selects chat from per-call useCompletionUrls", () =>
     Effect.gen(function* () {
       const plugin = yield* PluginV2.Service

packages/opencode/src/provider/provider.ts

@@ -151,7 +151,12 @@ type CustomDep = {
   get: (key: string) => Effect.Effect<string | undefined>
 }
 
-function selectAzureLanguageModel(sdk: any, modelID: string, useChat: boolean) {
+function selectAzureLanguageModel(sdk: any, modelID: string, useChat: boolean, model?: Model) {
+  if (
+    sdk.deepseek &&
+    [modelID, model?.id, model?.name, model?.family].some((value) => value?.toLowerCase().includes("deepseek"))
+  )
+    return sdk.deepseek(modelID)
   if (useChat && sdk.chat) return sdk.chat(modelID)
   if (sdk.responses) return sdk.responses(modelID)
   if (sdk.messages) return sdk.messages(modelID)
@@ -261,8 +266,8 @@ function custom(dep: CustomDep): Record<string, CustomLoader> {
 
       return {
         autoload: false,
-        async getModel(sdk: any, modelID: string, options?: Record<string, any>) {
-          return selectAzureLanguageModel(sdk, modelID, Boolean(options?.["useCompletionUrls"]))
+        async getModel(sdk: any, modelID: string, options?: Record<string, any>, model?: Model) {
+          return selectAzureLanguageModel(sdk, modelID, Boolean(options?.["useCompletionUrls"]), model)
         },
         options: {
           resourceName: resource,
@@ -281,8 +286,8 @@ function custom(dep: CustomDep): Record<string, CustomLoader> {
       const resourceName = yield* dep.get("AZURE_COGNITIVE_SERVICES_RESOURCE_NAME")
       return {
         autoload: false,
-        async getModel(sdk: any, modelID: string, options?: Record<string, any>) {
-          return selectAzureLanguageModel(sdk, modelID, Boolean(options?.["useCompletionUrls"]))
+        async getModel(sdk: any, modelID: string, options?: Record<string, any>, model?: Model) {
+          return selectAzureLanguageModel(sdk, modelID, Boolean(options?.["useCompletionUrls"]), model)
         },
         options: {
           baseURL: resourceName

packages/opencode/test/provider/provider.test.ts

@@ -809,6 +809,35 @@ it.instance("getSmallModel skips inferred models for Azure Cognitive Services",
   }),
 )
 
+it.instance(
+  "Azure uses the DeepSeek adapter for DeepSeek models",
+  Effect.gen(function* () {
+    yield* set("AZURE_API_KEY", "test-key")
+    const provider = yield* Provider.Service
+    const deepseek = yield* provider.getModel(ProviderV2.ID.azure, ModelV2.ID.make("deepseek-v4-pro"))
+    const chat = yield* provider.getModel(ProviderV2.ID.azure, ModelV2.ID.make("gpt-4o"))
+    const deepseekLanguage = yield* provider.getLanguage(deepseek)
+    const chatLanguage = yield* provider.getLanguage(chat)
+    expect((deepseekLanguage as { provider: string }).provider).toBe("azure.deepseek")
+    expect((deepseekLanguage as { modelId: string }).modelId).toBe("production-deployment")
+    expect((chatLanguage as { provider: string }).provider).toBe("azure.chat")
+  }),
+  {
+    config: {
+      provider: {
+        azure: {
+          npm: "@ai-sdk/azure",
+          options: { apiKey: "test-key", baseURL: "https://test.openai.azure.com/openai" },
+          models: {
+            "deepseek-v4-pro": { id: "production-deployment", options: { useCompletionUrls: true } },
+            "gpt-4o": { options: { useCompletionUrls: true } },
+          },
+        },
+      },
+    },
+  },
+)
+
 it.instance(
   "getSmallModel respects config small_model override",
   Effect.gen(function* () {