fix(opencode): enable adaptive reasoning for opus 4.7+ (#29769)

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

@@ -3223,6 +3223,12 @@ describe("ProviderTransform.variants", () => {
         efforts: ["low", "medium", "high", "xhigh", "max"],
         expectedHigh: { thinking: { type: "adaptive", display: "summarized" }, effort: "high" },
       },
+      {
+        name: "opus 4.8",
+        apiIds: ["claude-opus-4-8", "claude-opus-4.8"],
+        efforts: ["low", "medium", "high", "xhigh", "max"],
+        expectedHigh: { thinking: { type: "adaptive", display: "summarized" }, effort: "high" },
+      },
     ]) {
       for (const apiId of testCase.apiIds) {
         test(`${testCase.name} ${apiId} returns supported reasoning efforts`, () => {
@@ -3341,6 +3347,28 @@ describe("ProviderTransform.variants", () => {
       })
     })
 
+    test("anthropic opus 4.8 returns adaptive reasoning options with xhigh", () => {
+      const result = ProviderTransform.variants(
+        createMockModel({
+          id: "bedrock/anthropic-claude-opus-4.8",
+          providerID: "bedrock",
+          api: {
+            id: "anthropic.claude-opus-4.8",
+            url: "https://bedrock.amazonaws.com",
+            npm: "@ai-sdk/amazon-bedrock",
+          },
+        }),
+      )
+      expect(Object.keys(result)).toEqual(["low", "medium", "high", "xhigh", "max"])
+      expect(result.high).toEqual({
+        reasoningConfig: {
+          type: "adaptive",
+          maxReasoningEffort: "high",
+          display: "summarized",
+        },
+      })
+    })
+
     test("returns WIDELY_SUPPORTED_EFFORTS with reasoningConfig", () => {
       const model = createMockModel({
         id: "bedrock/llama-4",