fix(opencode): limit Bedrock change to variant summaries

packages/opencode/src/provider/transform.ts

@@ -1069,6 +1069,9 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
               type: "enabled",
               maxReasoningEffort: effort,
             },
+            ...(model.api.id.includes("openai.gpt-5")
+              ? { additionalModelRequestFields: { reasoning: { summary: "auto" } } }
+              : {}),
           },
         ]),
       )
@@ -1743,7 +1746,12 @@ function reasoningEffort(model: Provider.Model, effort: string) {
           },
         }
       if (model.api.id.includes("anthropic")) return
-      return { reasoningConfig: { type: "enabled", maxReasoningEffort: effort } }
+      return {
+        reasoningConfig: { type: "enabled", maxReasoningEffort: effort },
+        ...(model.api.id.includes("openai.gpt-5")
+          ? { additionalModelRequestFields: { reasoning: { summary: "auto" } } }
+          : {}),
+      }
     case "@ai-sdk/gateway":
       if (model.id.includes("anthropic")) return { thinking: { type: "adaptive", display: "summarized" }, effort }
       if (model.id.includes("google")) return { thinkingConfig: { includeThoughts: true, thinkingLevel: effort } }

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

@@ -3515,6 +3515,14 @@ describe("ProviderTransform.reasoningVariants", () => {
     ["ai-gateway-provider", { reasoningEffort: "high" }],
     ["merge-gateway-ai-sdk-provider", { reasoningEffort: "high" }],
     ["@ai-sdk/amazon-bedrock", { reasoningConfig: { type: "enabled", maxReasoningEffort: "high" } }],
+    [
+      "@ai-sdk/amazon-bedrock",
+      {
+        reasoningConfig: { type: "enabled", maxReasoningEffort: "high" },
+        additionalModelRequestFields: { reasoning: { summary: "auto" } },
+      },
+      "global.openai.gpt-5.6-luna",
+    ],
   ])("converts effort for %s", (npm, expected, ...args) => {
     const id = args[0] as string | undefined
     expect(ProviderTransform.reasoningVariants(model([{ type: "effort", values: ["high"] }]), target(npm, id))).toEqual(
@@ -3522,6 +3530,14 @@ describe("ProviderTransform.reasoningVariants", () => {
     )
   })
 
+  test("requests summaries for Bedrock GPT-5 fallback variants", () => {
+    const variants = ProviderTransform.variants(target("@ai-sdk/amazon-bedrock", "global.openai.gpt-5.6-luna"))
+    expect(variants.high).toEqual({
+      reasoningConfig: { type: "enabled", maxReasoningEffort: "high" },
+      additionalModelRequestFields: { reasoning: { summary: "auto" } },
+    })
+  })
+
   test("combines effort with extended thinking for Claude Opus 4.5", () => {
     expect(
       ProviderTransform.reasoningVariants(