fix: improve xai cache hit rate (#35970)

packages/opencode/package.json

@@ -73,7 +73,7 @@
     "@ai-sdk/provider": "3.0.8",
     "@ai-sdk/togetherai": "2.0.41",
     "@ai-sdk/vercel": "2.0.39",
-    "@ai-sdk/xai": "3.0.82",
+    "@ai-sdk/xai": "3.0.102",
     "@aws-sdk/credential-providers": "3.1057.0",
     "@clack/prompts": "1.0.0-alpha.1",
     "@effect/opentelemetry": "catalog:",

packages/opencode/src/provider/transform.ts

@@ -1127,7 +1127,12 @@ export function options(input: {
     }
   }
 
-  if (input.model.providerID === "openai" || input.providerOptions?.setCacheKey) {
+  if (
+    input.providerOptions?.setCacheKey !== false &&
+    (input.model.providerID === "openai" ||
+      input.model.api.npm === "@ai-sdk/xai" ||
+      input.providerOptions?.setCacheKey)
+  ) {
     result["promptCacheKey"] = input.sessionID
   }
 

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

@@ -73,7 +73,7 @@ describe("ProviderTransform.options - setCacheKey", () => {
     expect(result.promptCacheKey).toBeUndefined()
   })
 
-  test("should set promptCacheKey for openai provider regardless of setCacheKey", () => {
+  test("should set promptCacheKey for openai provider by default", () => {
     const openaiModel = {
       ...mockModel,
       providerID: "openai",
@@ -87,6 +87,56 @@ describe("ProviderTransform.options - setCacheKey", () => {
     expect(result.promptCacheKey).toBe(sessionID)
   })
 
+  test("should not set promptCacheKey for openai when explicitly disabled", () => {
+    const openaiModel = {
+      ...mockModel,
+      providerID: "openai",
+      api: {
+        id: "gpt-4",
+        url: "https://api.openai.com",
+        npm: "@ai-sdk/openai",
+      },
+    }
+    const result = ProviderTransform.options({
+      model: openaiModel,
+      sessionID,
+      providerOptions: { setCacheKey: false },
+    })
+    expect(result.promptCacheKey).toBeUndefined()
+  })
+
+  test("should set promptCacheKey for the xAI SDK by default regardless of provider ID", () => {
+    const xaiModel = {
+      ...mockModel,
+      providerID: "custom-xai",
+      api: {
+        id: "grok-4",
+        url: "https://api.x.ai",
+        npm: "@ai-sdk/xai",
+      },
+    }
+    const result = ProviderTransform.options({ model: xaiModel, sessionID, providerOptions: {} })
+    expect(result.promptCacheKey).toBe(sessionID)
+  })
+
+  test("should not set promptCacheKey for the xAI SDK when explicitly disabled", () => {
+    const xaiModel = {
+      ...mockModel,
+      providerID: "xai",
+      api: {
+        id: "grok-4",
+        url: "https://api.x.ai",
+        npm: "@ai-sdk/xai",
+      },
+    }
+    const result = ProviderTransform.options({
+      model: xaiModel,
+      sessionID,
+      providerOptions: { setCacheKey: false },
+    })
+    expect(result.promptCacheKey).toBeUndefined()
+  })
+
   test("should set store=false for openai provider", () => {
     const openaiModel = {
       ...mockModel,