diff --git a/packages/opencode/src/provider/transform.ts b/packages/opencode/src/provider/transform.ts
index 0ebd8bbf59..284fb0fcad 100644
--- a/packages/opencode/src/provider/transform.ts
+++ b/packages/opencode/src/provider/transform.ts
@@ -587,6 +587,12 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
     case "@ai-sdk/google-vertex/anthropic":
       // https://v5.ai-sdk.dev/providers/ai-sdk-providers/google-vertex#anthropic-provider
 
+      if (model.providerID === "github-copilot") {
+        if (model.api.id.includes("opus-4.7")) {
+          return Object.fromEntries(["medium"].map((effort) => [effort, { reasoningEffort: effort }]))
+        }
+      }
+
       if (adaptiveEfforts) {
         return Object.fromEntries(
           adaptiveEfforts.map((effort) => [