diff --git a/packages/opencode/src/session/processor.ts b/packages/opencode/src/session/processor.ts
index aac893075f00..4a6bb95b2f44 100644
--- a/packages/opencode/src/session/processor.ts
+++ b/packages/opencode/src/session/processor.ts
@@ -661,11 +661,12 @@ export const layer = Layer.effect(
         }
         ctx.reasoningMap = {}
 
-        yield* Effect.forEach(
-          Object.values(ctx.toolcalls),
-          (call) => Deferred.await(call.done).pipe(Effect.timeout("250 millis"), Effect.ignore),
-          { concurrency: "unbounded" },
-        )
+        if (!aborted) {
+          yield* Effect.forEach(Object.values(ctx.toolcalls), (call) => Deferred.await(call.done), {
+            concurrency: "unbounded",
+            discard: true,
+          })
+        }
 
         for (const toolCallID of Object.keys(ctx.toolcalls)) {
           const match = yield* readToolCall(toolCallID)
diff --git a/packages/opencode/test/session/processor-effect.test.ts b/packages/opencode/test/session/processor-effect.test.ts
index 78c7e4c64228..e58a6b7eaf86 100644
--- a/packages/opencode/test/session/processor-effect.test.ts
+++ b/packages/opencode/test/session/processor-effect.test.ts
@@ -1,6 +1,6 @@
 import { NodeFileSystem } from "@effect/platform-node"
 import { expect } from "bun:test"
-import { Cause, Effect, Exit, Fiber, Layer } from "effect"
+import { Cause, Effect, Exit, Fiber, Layer, Stream } from "effect"
 import path from "path"
 import type { Agent } from "../../src/agent/agent"
 import { Agent as AgentSvc } from "../../src/agent/agent"
@@ -195,6 +195,70 @@ const env = Layer.mergeAll(
 
 const it = testEffect(env)
 
+const lateToolLlm = Layer.succeed(
+  LLM.Service,
+  LLM.Service.of({
+    stream: () =>
+      Stream.make(
+        { type: "start" } satisfies LLM.Event,
+        { type: "start-step", request: {}, warnings: [] } satisfies LLM.Event,
+        { type: "tool-input-start", id: "call-1", toolName: "slow" } satisfies LLM.Event,
+        { type: "tool-call", toolCallId: "call-1", toolName: "slow", input: {} } satisfies LLM.Event,
+        {
+          type: "finish-step",
+          finishReason: "tool-calls",
+          rawFinishReason: "tool_calls",
+          response: { id: "res", modelId: "test-model", timestamp: new Date() },
+          providerMetadata: undefined,
+          usage: {
+            inputTokens: 1,
+            outputTokens: 1,
+            totalTokens: 2,
+            inputTokenDetails: {
+              noCacheTokens: undefined,
+              cacheReadTokens: undefined,
+              cacheWriteTokens: undefined,
+            },
+            outputTokenDetails: {
+              textTokens: undefined,
+              reasoningTokens: undefined,
+            },
+          },
+        } satisfies LLM.Event,
+        {
+          type: "finish",
+          finishReason: "tool-calls",
+          rawFinishReason: "tool_calls",
+          totalUsage: {
+            inputTokens: 1,
+            outputTokens: 1,
+            totalTokens: 2,
+            inputTokenDetails: {
+              noCacheTokens: undefined,
+              cacheReadTokens: undefined,
+              cacheWriteTokens: undefined,
+            },
+            outputTokenDetails: {
+              textTokens: undefined,
+              reasoningTokens: undefined,
+            },
+          },
+        } satisfies LLM.Event,
+      ),
+  }),
+)
+const lateToolEnv = Layer.mergeAll(
+  TestLLMServer.layer,
+  SessionProcessor.layer.pipe(
+    Layer.provide(lateToolLlm),
+    Layer.provide(summary),
+    Layer.provide(Image.defaultLayer),
+    Layer.provide(RuntimeFlags.layer({ experimentalEventSystem: true })),
+    Layer.provideMerge(deps),
+  ),
+)
+const itLateTool = testEffect(lateToolEnv)
+
 const boot = Effect.fn("test.boot")(function* () {
   const processors = yield* SessionProcessor.Service
   const session = yield* Session.Service
@@ -253,6 +317,64 @@ it.live("session.processor effect tests capture llm input cleanly", () =>
   ),
 )
 
+itLateTool.live("session.processor waits for late tool results before cleanup", () =>
+  provideTmpdirServer(
+    ({ dir }) =>
+      Effect.gen(function* () {
+        const { processors, session, provider } = yield* boot()
+
+        const chat = yield* session.create({})
+        const parent = yield* user(chat.id, "run tool")
+        const msg = yield* assistant(chat.id, parent.id, path.resolve(dir))
+        const mdl = yield* provider.getModel(ref.providerID, ref.modelID)
+        const handle = yield* processors.create({
+          assistantMessage: msg,
+          sessionID: chat.id,
+          model: mdl,
+        })
+
+        const run = yield* handle
+          .process({
+            user: {
+              id: parent.id,
+              sessionID: chat.id,
+              role: "user",
+              time: parent.time,
+              agent: parent.agent,
+              model: { providerID: ref.providerID, modelID: ref.modelID },
+            } satisfies MessageV2.User,
+            sessionID: chat.id,
+            model: mdl,
+            agent: agent(),
+            system: [],
+            messages: [{ role: "user", content: "run tool" }],
+            tools: {},
+          })
+          .pipe(Effect.forkChild)
+
+        yield* waitFor(
+          Effect.sync(() =>
+            MessageV2.parts(msg.id).find(
+              (part): part is MessageV2.ToolPart => part.type === "tool" && part.state.status === "running",
+            ),
+          ),
+          "timed out waiting for running tool",
+        )
+        yield* Effect.sleep("350 millis")
+        yield* handle.completeToolCall("call-1", { title: "slow", metadata: {}, output: "done" })
+
+        const exit = yield* Fiber.await(run).pipe(Effect.timeout("1 second"))
+        const tool = MessageV2.parts(msg.id).find((part): part is MessageV2.ToolPart => part.type === "tool")
+
+        expect(Exit.isSuccess(exit)).toBe(true)
+        expect(tool?.state.status).toBe("completed")
+        if (tool?.state.status !== "completed") return
+        expect(tool.state.output).toBe("done")
+      }),
+    { git: true, config: (url) => providerCfg(url) },
+  ),
+)
+
 it.live("session.processor effect tests preserve text start time", () =>
   provideTmpdirServer(
     ({ dir, llm }) =>