diff --git a/server/__tests__/awaiting-subagent-guard.test.js b/server/__tests__/awaiting-subagent-guard.test.js
new file mode 100644
index 00000000..65c0f883
--- /dev/null
+++ b/server/__tests__/awaiting-subagent-guard.test.js
@@ -0,0 +1,168 @@
+/**
+ * @file Regression: a BACKGROUND subagent's tool events must not clear a
+ * genuine 'notification' waiting flag held by the MAIN agent (blocked on the
+ * user via AskUserQuestion / permission). Before the fix, PreToolUse/PostToolUse
+ * cleared awaiting_input_since unconditionally, so a session that was truly
+ * "waiting for you" oscillated back to active on every subagent tool event —
+ * AI-Deck (12s poll) and deck-web (5s WS) then disagreed about the same session.
+ *
+ * The guard reuses the existing subagent-actor heuristic (findDeepestWorkingAgent
+ * while main is 'waiting'): when a subagent is the actor, only PASSIVE waits
+ * (stop/session_start/interrupted) are cleared; a 'notification' wait is
+ * preserved. When MAIN is the actor, clearing is unconditional (keeps the
+ * documented permission-mid-tool path intact).
+ *
+ * This test lives in the fork's own suite so a future upstream merge that
+ * silently reverts the guard fails loudly here (home-network monitor fork,
+ * see decisions/).
+ */
+
+const { describe, it, before, after } = require("node:test");
+const assert = require("node:assert/strict");
+const path = require("path");
+const os = require("os");
+const http = require("http");
+
+const TEST_DB = path.join(os.tmpdir(), `awaiting-guard-${Date.now()}-${process.pid}.db`);
+process.env.DASHBOARD_DB_PATH = TEST_DB;
+process.env.DASHBOARD_LIVENESS_PROBE = "0";
+
+const { createApp, startServer } = require("../index");
+
+let server;
+let BASE;
+
+function fetch(urlPath, options = {}) {
+  return new Promise((resolve, reject) => {
+    const url = new URL(urlPath, BASE);
+    const req = http.request(
+      {
+        hostname: url.hostname,
+        port: url.port,
+        path: url.pathname + url.search,
+        method: options.method || "GET",
+        headers: { "Content-Type": "application/json", ...options.headers },
+      },
+      (res) => {
+        let body = "";
+        res.on("data", (c) => (body += c));
+        res.on("end", () => {
+          let parsed;
+          try {
+            parsed = JSON.parse(body);
+          } catch {
+            parsed = body;
+          }
+          resolve({ status: res.statusCode, body: parsed });
+        });
+      }
+    );
+    req.on("error", reject);
+    if (options.body) req.write(JSON.stringify(options.body));
+    req.end();
+  });
+}
+
+const post = (p, body) => fetch(p, { method: "POST", body });
+const hook = (hook_type, data) => post("/api/hooks/event", { hook_type, data });
+const sessionOf = async (id) => (await fetch(`/api/sessions/${id}`)).body.session;
+
+/**
+ * Drive a session into: main agent 'waiting' with the given reason, AND a live
+ * working subagent (so findDeepestWorkingAgent returns it). Returns nothing;
+ * asserts each precondition so a harness regression is obvious.
+ */
+async function sessionWaitingWithWorkingSubagent(sid, { notification }) {
+  await hook("SessionStart", { session_id: sid });
+  // UserPromptSubmit clears the session_start wait and promotes main → working.
+  await hook("UserPromptSubmit", { session_id: sid, prompt: "go" });
+  // Main (working) spawns a subagent → subagent row inserted with status working.
+  await hook("PreToolUse", {
+    session_id: sid,
+    tool_name: "Agent",
+    tool_input: { subagent_type: "reviewer", prompt: "review" },
+  });
+  // Now block the MAIN agent. A waiting-for-user Notification stamps
+  // reason='notification'; a Stop stamps the passive reason='stop'.
+  if (notification) {
+    await hook("Notification", { session_id: sid, message: "Claude is waiting for your input" });
+  } else {
+    await hook("Stop", { session_id: sid });
+  }
+  const sess = await sessionOf(sid);
+  assert.ok(sess.awaiting_input_since, "precondition: session should be awaiting");
+  assert.equal(
+    sess.awaiting_reason,
+    notification ? "notification" : "stop",
+    "precondition: expected awaiting_reason"
+  );
+}
+
+before(async () => {
+  server = await startServer(createApp(), 0);
+  BASE = `http://127.0.0.1:${server.address().port}`;
+});
+
+after(() => {
+  if (server) server.close();
+});
+
+describe("awaiting guard: subagent tool events vs. main-agent waiting", () => {
+  it("PRESERVES a 'notification' wait when a background subagent fires PreToolUse", async () => {
+    const sid = "guard-notif-pre";
+    await sessionWaitingWithWorkingSubagent(sid, { notification: true });
+
+    // Subagent (deepest working, main is waiting) runs a tool. This must NOT
+    // clear the main agent's genuine "waiting for you" flag.
+    await hook("PreToolUse", { session_id: sid, tool_name: "Bash" });
+
+    const sess = await sessionOf(sid);
+    assert.ok(sess.awaiting_input_since, "notification wait must survive subagent PreToolUse");
+    assert.equal(sess.awaiting_reason, "notification");
+  });
+
+  it("PRESERVES a 'notification' wait when a background subagent fires PostToolUse", async () => {
+    const sid = "guard-notif-post";
+    await sessionWaitingWithWorkingSubagent(sid, { notification: true });
+
+    await hook("PostToolUse", { session_id: sid, tool_name: "Bash" });
+
+    const sess = await sessionOf(sid);
+    assert.ok(sess.awaiting_input_since, "notification wait must survive subagent PostToolUse");
+    assert.equal(sess.awaiting_reason, "notification");
+  });
+
+  it("CLEARS a passive 'stop' wait when a background subagent fires a tool event", async () => {
+    // Passive-clear is desirable: a backgrounded subagent's activity should flip
+    // a merely-Stopped session back to active ("done/idle only while no agent works").
+    const sid = "guard-stop-pre";
+    await sessionWaitingWithWorkingSubagent(sid, { notification: false });
+
+    await hook("PreToolUse", { session_id: sid, tool_name: "Bash" });
+
+    const sess = await sessionOf(sid);
+    assert.equal(
+      sess.awaiting_input_since,
+      null,
+      "passive stop wait should be cleared by subagent activity"
+    );
+    assert.equal(sess.awaiting_reason, null);
+  });
+
+  it("CLEARS a 'notification' wait when MAIN (no working subagent) resumes with a tool", async () => {
+    // Control: main was waiting on the user, no subagent running. A PreToolUse
+    // means main itself resumed — clearing is correct (unchanged behaviour).
+    const sid = "guard-notif-mainactor";
+    await hook("SessionStart", { session_id: sid });
+    await hook("UserPromptSubmit", { session_id: sid, prompt: "go" });
+    await hook("Notification", { session_id: sid, message: "Claude is waiting for your input" });
+    let sess = await sessionOf(sid);
+    assert.ok(sess.awaiting_input_since && sess.awaiting_reason === "notification", "precondition");
+
+    await hook("PreToolUse", { session_id: sid, tool_name: "Bash" });
+
+    sess = await sessionOf(sid);
+    assert.equal(sess.awaiting_input_since, null, "main resuming must clear its own wait");
+    assert.equal(sess.awaiting_reason, null);
+  });
+});
diff --git a/server/routes/hooks.js b/server/routes/hooks.js
index b07b0f90..883009ca 100644
--- a/server/routes/hooks.js
+++ b/server/routes/hooks.js
@@ -57,6 +57,51 @@ function clearAwaitingInput(sessionId, mainAgentId, broadcastUpdates) {
   }
 }
 
+// Reason-aware guarded clear (2026-07-17, AI-Deck/deck-web fork patch — see
+// decisions/ in the home-network repo). PreToolUse/PostToolUse clear the
+// waiting flag on the assumption that a tool event means the human resumed.
+// That assumption breaks when the MAIN agent is blocked on the user
+// (AskUserQuestion / permission) while a BACKGROUND subagent keeps firing
+// PreToolUse/PostToolUse: the subagent's tool event is not the human
+// responding, yet it wiped the flag — so AI-Deck/deck-web lost the "waiting
+// for you" signal (it oscillated on/off in seconds).
+//
+// The existing subagent-actor heuristic (findDeepestWorkingAgent, used just
+// below in each case) already tells us when a subagent — not main — is the
+// actor. We reuse it here: when a subagent is the actor we clear ONLY passive
+// waits (stop/session_start/interrupted); a genuine 'notification' wait (main
+// blocked on the user) is preserved. When MAIN is the actor we clear
+// unconditionally, exactly as before — this keeps the documented
+// permission-mid-tool path (PostToolUse clearing an approved prompt) intact.
+//
+// Passive-clear-by-subagent is deliberate and desirable: it is what lets a
+// backgrounded subagent's activity flip a session that merely Stop-ed
+// (reason='stop') back to active — i.e. "done/idle only while no agent works".
+function clearAwaitingInputRespectingActor(
+  sessionId,
+  mainAgentId,
+  subagentIsActor,
+  broadcastUpdates
+) {
+  if (subagentIsActor) {
+    const sess = stmts.getSession.get(sessionId);
+    if (sess && sess.awaiting_reason === "notification") {
+      // Main is blocked on the user; a subagent tool event must not clear it.
+      return;
+    }
+  }
+  clearAwaitingInput(sessionId, mainAgentId, broadcastUpdates);
+}
+
+// True when the deepest currently-working agent is a subagent while the main
+// agent is in 'waiting' — i.e. an incoming tool event is attributable to a
+// subagent, not to the main agent resuming. Mirrors the inline heuristic the
+// PreToolUse/PostToolUse cases already use for agent attribution.
+function subagentIsActorNow(sessionId, mainAgent) {
+  if (!mainAgent || mainAgent.status !== "waiting") return false;
+  return !!stmts.findDeepestWorkingAgent.get(sessionId, sessionId);
+}
+
 // Land a session that was cancelled with no hook (Esc) in the same
 // waiting + awaiting-input state a normal Stop produces, and log a timeline
 // event. Used by both watchdog recovery paths: the transcript-marker path
@@ -334,8 +379,17 @@ const processEvent = db.transaction((hookType, data) => {
 
       // PreToolUse means Claude is actively running a tool, ergo the user
       // has resumed (Stop only fires at end of turn — Claude can't start a
-      // new tool call without fresh user input). Clear waiting now.
-      clearAwaitingInput(sessionId, mainAgentId, true);
+      // new tool call without fresh user input). Clear waiting now — UNLESS a
+      // background subagent is the actor and main is blocked on the user
+      // (reason='notification'), in which case the flag is preserved
+      // (clearAwaitingInputRespectingActor). Computed before the clear because
+      // the Agent-spawn branch below mutates agent rows.
+      clearAwaitingInputRespectingActor(
+        sessionId,
+        mainAgentId,
+        subagentIsActorNow(sessionId, mainAgent),
+        true
+      );
 
       // If the tool is Agent, a subagent is being created
       if (toolName === "Agent") {
@@ -414,7 +468,14 @@ const processEvent = db.transaction((hookType, data) => {
       // Code prompts the user mid-tool). The Notification stamps waiting,
       // the user approves, the tool completes, PostToolUse arrives. Without
       // a clear here, we'd be stuck in waiting until the next PreToolUse.
-      clearAwaitingInput(sessionId, mainAgentId, true);
+      // Same actor-guard as PreToolUse: a background subagent's PostToolUse
+      // must not clear a genuine 'notification' wait held by the main agent.
+      clearAwaitingInputRespectingActor(
+        sessionId,
+        mainAgentId,
+        subagentIsActorNow(sessionId, mainAgent),
+        true
+      );
 
       // NOTE: PostToolUse for "Agent" tool fires immediately when a subagent is
       // backgrounded — it does NOT mean the subagent finished its work.