diff --git a/apps/server/src/mcp/OrchestratorMcpService.test.ts b/apps/server/src/mcp/OrchestratorMcpService.test.ts
index 5f5cae7563621..7bf7d2efe2c82 100644
--- a/apps/server/src/mcp/OrchestratorMcpService.test.ts
+++ b/apps/server/src/mcp/OrchestratorMcpService.test.ts
@@ -30,14 +30,17 @@ import {
 import { checkpointWorkspace } from "@t3tools/provider-testing/replayWorkspace";
 import * as DateTime from "effect/DateTime";
 import * as Deferred from "effect/Deferred";
+import * as Duration from "effect/Duration";
 import * as Effect from "effect/Effect";
 import * as Fiber from "effect/Fiber";
 import * as Layer from "effect/Layer";
+import * as Option from "effect/Option";
 import * as Queue from "effect/Queue";
 import * as Ref from "effect/Ref";
 import * as Result from "effect/Result";
 import * as Schema from "effect/Schema";
 import * as Stream from "effect/Stream";
+import * as TestClock from "effect/testing/TestClock";
 
 import { CodexProviderCapabilitiesV2 } from "../orchestration-v2/Adapters/CodexAdapterV2.ts";
 import * as CommandReceiptStore from "../orchestration-v2/CommandReceiptStore.ts";
@@ -1274,6 +1277,7 @@ describe("OrchestratorMcpService provider resolution", () => {
     "child run completion",
     "child question",
     "child approval",
+    "Node fetch's 300 s idle timeout",
   ] as const)("a task wait still returns on %s", (wake) =>
     Effect.gen(function* () {
       const events = yield* Queue.unbounded<OrchestrationV2StoredEvent>();
@@ -1379,6 +1383,24 @@ describe("OrchestratorMcpService provider resolution", () => {
           .delegateTask(scope, { task: "Review the change.", mode: "wait" })
           .pipe(Effect.forkChild);
         yield* Deferred.await(subscribed);
+        if (wake === "Node fetch's 300 s idle timeout") {
+          // Nothing is written during the wait, so undici drops the call at 300 s, before any handle.
+          const beforeClientTimeout = yield* Fiber.join(waiting).pipe(
+            Effect.timeoutOption(Duration.seconds(299)),
+            Effect.forkChild,
+          );
+          yield* TestClock.adjust(Duration.seconds(299));
+          const result = yield* Fiber.join(beforeClientTimeout);
+          assert.isTrue(
+            Option.isSome(result),
+            "a wait without timeoutMs was still silent at 299 s, so a Node MCP client loses the taskId",
+          );
+          if (Option.isSome(result)) {
+            assert.equal(result.value.taskId, taskId);
+            assert.isTrue(result.value.waitTimedOut);
+          }
+          return;
+        }
         ready = true;
         if (wake === "parent completion") {
           yield* Queue.offer(events, {
diff --git a/apps/server/src/mcp/OrchestratorMcpService.ts b/apps/server/src/mcp/OrchestratorMcpService.ts
index 71cf0efeda10a..b74619e7b28f4 100644
--- a/apps/server/src/mcp/OrchestratorMcpService.ts
+++ b/apps/server/src/mcp/OrchestratorMcpService.ts
@@ -131,6 +131,8 @@ import * as PeerForwarding from "../peer/PeerForwarding.ts";
 import * as RemoteDelegation from "../peer/RemoteDelegation.ts";
 
 const DEFAULT_WAIT_TIMEOUT_MS = 10 * 60 * 1_000;
+// Nothing is written while a task wait blocks, and Node fetch drops a silent call at 300 s.
+const DEFAULT_TASK_WAIT_TIMEOUT_MS = 4 * 60 * 1_000;
 const MAX_WAIT_TIMEOUT_MS = 60 * 60 * 1_000;
 const TASK_WAKE_EVENTS = [
   { thread: "parent", eventType: "subagent.updated" },
@@ -1698,7 +1700,7 @@ const make = Effect.gen(function* () {
   ): Effect.fn.Return<OrchestratorMcpDelegateTaskResult, OrchestratorMcpFailure> {
     const timeoutMs = Math.min(
       MAX_WAIT_TIMEOUT_MS,
-      Math.max(1, requestedTimeoutMs ?? DEFAULT_WAIT_TIMEOUT_MS),
+      Math.max(1, requestedTimeoutMs ?? DEFAULT_TASK_WAIT_TIMEOUT_MS),
     );
     const upgradeWake = threadManagement
       .dispatch({
diff --git a/apps/server/src/provider/agentContextBudget.json b/apps/server/src/provider/agentContextBudget.json
index 486c4314927ad..8ff4546b354a4 100644
--- a/apps/server/src/provider/agentContextBudget.json
+++ b/apps/server/src/provider/agentContextBudget.json
@@ -1,5 +1,5 @@
 {
   "claudeSystemAppendBytes": 5597,
   "codexAdditionalContextBytes": 7327,
-  "mcpToolListJsonBytes": 48131
+  "mcpToolListJsonBytes": 48130
 }
diff --git a/packages/contracts/src/orchestratorMcp.ts b/packages/contracts/src/orchestratorMcp.ts
index 91f56d7b763f8..a036620022d19 100644
--- a/packages/contracts/src/orchestratorMcp.ts
+++ b/packages/contracts/src/orchestratorMcp.ts
@@ -184,7 +184,7 @@ export const OrchestratorMcpDelegateTaskInput = Schema.Struct({
     }),
   ),
   timeoutMs: Schema.optional(Schema.Finite).annotate({
-    description: "Mode 'wait' only. Default 10 min. A timeout does not cancel the child.",
+    description: "Mode 'wait' only. Default 4 min. A timeout does not cancel the child.",
   }),
   clientRequestId: Schema.optional(OrchestratorMcpClientRequestId),
   runtimeMode: Schema.optional(