diff --git a/packages/opencode/src/tool/task.ts b/packages/opencode/src/tool/task.ts
index d127fba38..8f27f570b 100644
--- a/packages/opencode/src/tool/task.ts
+++ b/packages/opencode/src/tool/task.ts
@@ -7,6 +7,7 @@ import { MessageV2 } from "../session/message-v2"
 import { Identifier } from "../id/id"
 import { Agent } from "../agent/agent"
 import { SessionPrompt } from "../session/prompt"
+import { defer } from "@/util/defer"
 
 export const TaskTool = Tool.define("task", async () => {
   const agents = await Agent.list().then((x) => x.filter((a) => a.mode !== "primary"))
@@ -61,9 +62,11 @@ export const TaskTool = Tool.define("task", async () => {
         providerID: msg.info.providerID,
       }
 
-      ctx.abort.addEventListener("abort", () => {
+      function cancel() {
         SessionPrompt.cancel(session.id)
-      })
+      }
+      ctx.abort.addEventListener("abort", cancel)
+      using _ = defer(() => ctx.abort.removeEventListener("abort", cancel))
       const promptParts = await SessionPrompt.resolvePromptParts(params.prompt)
       const result = await SessionPrompt.prompt({
         messageID,