fix(opencode): preserve variant for delegated tasks (#30630)

packages/opencode/src/tool/task.ts

@@ -172,6 +172,7 @@ export const TaskTool = Tool.define(
         Effect.orDie,
       )
       if (msg.info.role !== "assistant") return yield* Effect.fail(new Error("Not an assistant message"))
+      const variant = msg.info.variant
 
       const model = next.model ?? {
         modelID: msg.info.modelID,
@@ -201,6 +202,7 @@ export const TaskTool = Tool.define(
             modelID: model.modelID,
             providerID: model.providerID,
           },
+          variant: next.model ? undefined : variant,
           agent: next.name,
           tools: {
             ...(next.permission.some((rule) => rule.permission === "todowrite") ? {} : { todowrite: false }),
@@ -221,6 +223,7 @@ export const TaskTool = Tool.define(
           .prompt({
             sessionID: ctx.sessionID,
             agent: currentParent.agent ?? ctx.agent,
+            variant,
             parts: [
               {
                 type: "text",