diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index bcb115edf41..83c34cfed1a 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -1024,9 +1024,20 @@ export namespace Provider {
         })
       }
 
+      // Special case: Azure Cognitive Services with Anthropic models uses @ai-sdk/anthropic
+      const isAzureClaude = model.providerID === "azure-cognitive-services" && model.api.id.includes("claude")
+      if (isAzureClaude) {
+        const resourceName = Env.get("AZURE_COGNITIVE_SERVICES_RESOURCE_NAME")
+        if (resourceName) options["baseURL"] = `https://${resourceName}.services.ai.azure.com/anthropic/v1/`
+      }
+
       // Special case: google-vertex-anthropic uses a subpath import
       const bundledKey =
-        model.providerID === "google-vertex-anthropic" ? "@ai-sdk/google-vertex/anthropic" : model.api.npm
+        model.providerID === "google-vertex-anthropic"
+          ? "@ai-sdk/google-vertex/anthropic"
+          : isAzureClaude
+            ? "@ai-sdk/anthropic"
+            : model.api.npm
       const bundledFn = BUNDLED_PROVIDERS[bundledKey]
       if (bundledFn) {
         log.info("using bundled provider", { providerID: model.providerID, pkg: bundledKey })
@@ -1092,10 +1103,13 @@ export namespace Provider {
     const provider = s.providers[model.providerID]
     const sdk = await getSDK(model)
 
+    // Skip custom model loader for Azure Cognitive Services with Claude models
+    // since they use @ai-sdk/anthropic which uses sdk.languageModel()
+    const isAzureClaude = model.providerID === "azure-cognitive-services" && model.api.id.includes("claude")
+    const loader = isAzureClaude ? undefined : s.modelLoaders[model.providerID]
+
     try {
-      const language = s.modelLoaders[model.providerID]
-        ? await s.modelLoaders[model.providerID](sdk, model.api.id, provider.options)
-        : sdk.languageModel(model.api.id)
+      const language = loader ? await loader(sdk, model.api.id, provider.options) : sdk.languageModel(model.api.id)
       s.models.set(key, language)
       return language
     } catch (e) {
diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index b803bd66ce1..285a9a6e613 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -45,7 +45,8 @@ export namespace ProviderTransform {
   ): ModelMessage[] {
     // Anthropic rejects messages with empty content - filter out empty string messages
     // and remove empty text/reasoning parts from array content
-    if (model.api.npm === "@ai-sdk/anthropic") {
+    const isAzureClaude = model.providerID === "azure-cognitive-services" && model.api.id.includes("claude")
+    if (model.api.npm === "@ai-sdk/anthropic" || isAzureClaude) {
       msgs = msgs
         .map((msg) => {
           if (typeof msg.content === "string") {
@@ -325,6 +326,15 @@ export namespace ProviderTransform {
     const id = model.id.toLowerCase()
     if (id.includes("deepseek") || id.includes("minimax") || id.includes("glm") || id.includes("mistral")) return {}
 
+    // Azure Cognitive Services with Claude models uses Anthropic thinking config
+    const isAzureClaude = model.providerID === "azure-cognitive-services" && model.api.id.includes("claude")
+    if (isAzureClaude) {
+      return {
+        high: { thinking: { type: "enabled", budgetTokens: 16000 } },
+        max: { thinking: { type: "enabled", budgetTokens: 31999 } },
+      }
+    }
+
     // see: https://docs.x.ai/docs/guides/reasoning#control-how-hard-the-model-thinks
     if (id.includes("grok") && id.includes("grok-3-mini")) {
       if (model.api.npm === "@openrouter/ai-sdk-provider") {
@@ -610,6 +620,12 @@ export namespace ProviderTransform {
   }
 
   export function providerOptions(model: Provider.Model, options: { [x: string]: any }) {
+    // Azure Cognitive Services with Claude models uses Anthropic provider options
+    const isAzureClaude = model.providerID === "azure-cognitive-services" && model.api.id.includes("claude")
+    if (isAzureClaude) {
+      return { anthropic: options }
+    }
+
     const key = sdkKey(model.api.npm) ?? model.providerID
     return { [key]: options }
   }
diff --git a/packages/opencode/src/session/llm.ts b/packages/opencode/src/session/llm.ts
index 1029b45ea0d..02e7e394f91 100644
--- a/packages/opencode/src/session/llm.ts
+++ b/packages/opencode/src/session/llm.ts
@@ -131,14 +131,13 @@ export namespace LLM {
       },
     )
 
+    // Azure Cognitive Services with Claude models uses Anthropic SDK
+    const isAzureClaude = input.model.providerID === "azure-cognitive-services" && input.model.api.id.includes("claude")
+    const npm = isAzureClaude ? "@ai-sdk/anthropic" : input.model.api.npm
+
     const maxOutputTokens = isCodex
       ? undefined
-      : ProviderTransform.maxOutputTokens(
-          input.model.api.npm,
-          params.options,
-          input.model.limit.output,
-          OUTPUT_TOKEN_MAX,
-        )
+      : ProviderTransform.maxOutputTokens(npm, params.options, input.model.limit.output, OUTPUT_TOKEN_MAX)
 
     const tools = await resolveTools(input)