diff --git a/packages/opencode/src/tool/task.ts b/packages/opencode/src/tool/task.ts
index df912caefa..2d57720e9e 100644
--- a/packages/opencode/src/tool/task.ts
+++ b/packages/opencode/src/tool/task.ts
@@ -7,7 +7,6 @@ import { SessionID, MessageID } from "../session/schema"
 import { MessageV2 } from "../session/message-v2"
 import { Agent } from "../agent/agent"
 import { SessionPrompt } from "../session/prompt"
-import { iife } from "@/util/iife"
 import { Config } from "../config/config"
 import { Permission } from "@/permission"
 
@@ -68,7 +67,7 @@ export const TaskTool = Tool.defineEffect(
         )
       }
 
-      const next = yield* agent.get(params.subagent_type).pipe(Effect.catch(() => Effect.succeed(undefined)))
+      const next = yield* agent.get(params.subagent_type)
       if (!next) {
         return yield* Effect.fail(new Error(`Unknown agent type: ${params.subagent_type} is not a valid agent type`))
       }
@@ -76,14 +75,17 @@ export const TaskTool = Tool.defineEffect(
       const hasTask = next.permission.some((rule) => rule.permission === "task")
       const hasTodo = next.permission.some((rule) => rule.permission === "todowrite")
 
-      const session = yield* Effect.promise(() =>
-        iife(async () => {
-          if (params.task_id) {
-            const found = await Session.get(SessionID.make(params.task_id)).catch(() => {})
-            if (found) return found
-          }
-
-          return Session.create({
+      const taskID = params.task_id
+      const session = taskID
+        ? yield* Effect.promise(() => {
+            const id = SessionID.make(taskID)
+            return Session.get(id).catch(() => undefined)
+          })
+        : undefined
+      const nextSession =
+        session ??
+        (yield* Effect.promise(() =>
+          Session.create({
             parentID: ctx.sessionID,
             title: params.description + ` (@${next.name} subagent)`,
             permission: [
@@ -111,9 +113,8 @@ export const TaskTool = Tool.defineEffect(
                 permission: item,
               })) ?? []),
             ],
-          })
-        }),
-      )
+          }),
+        ))
 
       const msg = yield* Effect.sync(() => MessageV2.get({ sessionID: ctx.sessionID, messageID: ctx.messageID }))
       if (msg.info.role !== "assistant") return yield* Effect.fail(new Error("Not an assistant message"))
@@ -126,7 +127,7 @@ export const TaskTool = Tool.defineEffect(
       ctx.metadata({
         title: params.description,
         metadata: {
-          sessionId: session.id,
+          sessionId: nextSession.id,
           model,
         },
       })
@@ -134,54 +135,51 @@ export const TaskTool = Tool.defineEffect(
       const messageID = MessageID.ascending()
 
       function cancel() {
-        SessionPrompt.cancel(session.id)
+        SessionPrompt.cancel(nextSession.id)
       }
       return yield* Effect.acquireUseRelease(
         Effect.sync(() => {
           ctx.abort.addEventListener("abort", cancel)
         }),
-        () => Effect.promise(() => SessionPrompt.resolvePromptParts(params.prompt)),
+        () =>
+          Effect.gen(function* () {
+            const parts = yield* Effect.promise(() => SessionPrompt.resolvePromptParts(params.prompt))
+            const result = yield* Effect.promise(() =>
+              SessionPrompt.prompt({
+                messageID,
+                sessionID: nextSession.id,
+                model: {
+                  modelID: model.modelID,
+                  providerID: model.providerID,
+                },
+                agent: next.name,
+                tools: {
+                  ...(hasTodo ? {} : { todowrite: false }),
+                  ...(hasTask ? {} : { task: false }),
+                  ...Object.fromEntries((cfg.experimental?.primary_tools ?? []).map((item) => [item, false])),
+                },
+                parts,
+              }),
+            )
+            return {
+              title: params.description,
+              metadata: {
+                sessionId: nextSession.id,
+                model,
+              },
+              output: [
+                `task_id: ${nextSession.id} (for resuming to continue this task if needed)`,
+                "",
+                "<task_result>",
+                result.parts.findLast((item) => item.type === "text")?.text ?? "",
+                "</task_result>",
+              ].join("\n"),
+            }
+          }),
         () =>
           Effect.sync(() => {
             ctx.abort.removeEventListener("abort", cancel)
           }),
-      ).pipe(
-        Effect.flatMap((parts) =>
-          Effect.promise(() =>
-            SessionPrompt.prompt({
-              messageID,
-              sessionID: session.id,
-              model: {
-                modelID: model.modelID,
-                providerID: model.providerID,
-              },
-              agent: next.name,
-              tools: {
-                ...(hasTodo ? {} : { todowrite: false }),
-                ...(hasTask ? {} : { task: false }),
-                ...Object.fromEntries((cfg.experimental?.primary_tools ?? []).map((item) => [item, false])),
-              },
-              parts,
-            }),
-          ),
-        ),
-        Effect.map((result) => {
-          const text = result.parts.findLast((item) => item.type === "text")?.text ?? ""
-          return {
-            title: params.description,
-            metadata: {
-              sessionId: session.id,
-              model,
-            },
-            output: [
-              `task_id: ${session.id} (for resuming to continue this task if needed)`,
-              "",
-              "<task_result>",
-              text,
-              "</task_result>",
-            ].join("\n"),
-          }
-        }),
       )
     })
 
diff --git a/packages/opencode/test/session/prompt-effect.test.ts b/packages/opencode/test/session/prompt-effect.test.ts
index 0c1da8a4a1..d2c6373e6f 100644
--- a/packages/opencode/test/session/prompt-effect.test.ts
+++ b/packages/opencode/test/session/prompt-effect.test.ts
@@ -1,5 +1,5 @@
 import { NodeFileSystem } from "@effect/platform-node"
-import { expect, spyOn } from "bun:test"
+import { expect } from "bun:test"
 import { Cause, Effect, Exit, Fiber, Layer } from "effect"
 import path from "path"
 import z from "zod"
@@ -13,7 +13,6 @@ import { MCP } from "../../src/mcp"
 import { Permission } from "../../src/permission"
 import { Plugin } from "../../src/plugin"
 import { Provider as ProviderSvc } from "../../src/provider/provider"
-import type { Provider } from "../../src/provider/provider"
 import { ModelID, ProviderID } from "../../src/provider/schema"
 import { Question } from "../../src/question"
 import { Todo } from "../../src/session/todo"
@@ -626,7 +625,7 @@ it.live(
   "cancel finalizes subtask tool state",
   () =>
     provideTmpdirInstance(
-      (dir) =>
+      () =>
         Effect.gen(function* () {
           const ready = defer<void>()
           const aborted = defer<void>()
@@ -642,6 +641,13 @@ it.live(
               command: z.string().optional(),
             }),
             execute: async (_args, ctx) => {
+              ctx.metadata({
+                title: "inspect bug",
+                metadata: {
+                  sessionId: SessionID.make("task"),
+                  model: ref,
+                },
+              })
               ready.resolve()
               ctx.abort.addEventListener("abort", () => aborted.resolve(), { once: true })
               await new Promise<void>(() => {})
@@ -674,11 +680,19 @@ it.live(
           expect(taskMsg?.info.role).toBe("assistant")
           if (!taskMsg || taskMsg.info.role !== "assistant") return
 
-          const tool = toolPart(taskMsg.parts)
-          expect(tool?.type).toBe("tool")
+          const tool = errorTool(taskMsg.parts)
           if (!tool) return
 
-          expect(tool.state.status).not.toBe("running")
+          expect(tool.state.error).toBe("Cancelled")
+          expect(tool.state.input).toEqual({
+            description: "inspect bug",
+            prompt: "look into the cache key path",
+            subagent_type: "general",
+          })
+          expect(tool.state.metadata).toEqual({
+            sessionId: SessionID.make("task"),
+            model: ref,
+          })
           expect(taskMsg.info.time.completed).toBeDefined()
           expect(taskMsg.info.finish).toBeDefined()
         }),