fix(opencode): attribute task child agent on creation (#30786)

packages/opencode/src/tool/task.ts

@@ -128,6 +128,7 @@ export const TaskTool = Tool.define(
         (yield* sessions.create({
           parentID: ctx.sessionID,
           title: params.description + ` (@${next.name} subagent)`,
+          agent: next.name,
           permission: [
             ...deriveSubagentSessionPermission({
               parentSessionPermission: parent.permission ?? [],

packages/opencode/test/tool/task.test.ts

@@ -412,6 +412,7 @@ describe("tool.task", () => {
 
         const child = yield* sessions.get(result.metadata.sessionId)
         expect(child.parentID).toBe(chat.id)
+        expect(child.agent).toBe("reviewer")
         expect(child.permission).toEqual([
           {
             permission: "todowrite",