diff --git a/src/main.ts b/src/main.ts
index 00c521e..00bab99 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -41,6 +41,13 @@ if (started) {
   app.quit();
 }
 
+// Safety net — observability only, never recovery: rejections that escape the
+// local catches are logged, not swallowed or recovered. Local `.catch`
+// handling remains the real mechanism (hardening plan, Fase 4).
+process.on('unhandledRejection', (reason) => {
+  console.error('[dw] unhandledRejection:', reason);
+});
+
 let ptys: PtyManager | null = null;
 let broker: Broker | null = null;
 
diff --git a/src/main/broker.test.ts b/src/main/broker.test.ts
index 32af4b1..3dd43ae 100644
--- a/src/main/broker.test.ts
+++ b/src/main/broker.test.ts
@@ -303,6 +303,7 @@ describe('Broker (unit, stub deps)', () => {
   const injected: Array<{ to: string; body: string }> = [];
   const awaited: Array<{ to: string; timeoutMs: number }> = [];
   const slowTargets = new Set<string>();
+  const failingTargets = new Set<string>();
   const rolloverTargets = new Set<string>();
   const spawned: Array<Record<string, unknown>> = [];
   const killed: string[] = [];
@@ -318,6 +319,9 @@ describe('Broker (unit, stub deps)', () => {
       // isolates just the new output — exactly like the real PTY mirror.
       awaitQuiet: async (id: string, timeoutMs: number) => {
         awaited.push({ to: id, timeoutMs });
+        // A peer whose quiet-wait explodes: the exchange throws mid-ask, so
+        // handleAsk's Promise.all rejects — the dispatch catch must answer.
+        if (failingTargets.has(id)) throw new Error('exchange exploded');
         if (slowTargets.has(id)) await new Promise((r) => setTimeout(r, 400));
         const answer = answers.get(id);
         if (answer) captured.set(id, (captured.get(id) ?? '') + answer);
@@ -387,6 +391,7 @@ describe('Broker (unit, stub deps)', () => {
     answers.clear();
     captured.clear();
     slowTargets.clear();
+    failingTargets.clear();
     rolloverTargets.clear();
     injected.length = 0;
     awaited.length = 0;
@@ -503,6 +508,16 @@ describe('Broker (unit, stub deps)', () => {
     expect(res).toEqual({ ok: false, error: 'ask needs a terminal target' });
   });
 
+  it('answers the socket when an ask explodes mid-exchange', async () => {
+    // The exchange throws for this peer, so handleAsk's internal Promise.all
+    // rejects; the dispatch catch must answer the socket instead of leaking
+    // an unhandled rejection.
+    addTerminal('peer1', 'Peer One');
+    failingTargets.add('peer1');
+    const res = await rpc(sock, { cmd: 'ask', from: 'lead', target: 'Peer One', body: 'hi' });
+    expect(res).toEqual({ ok: false, error: 'exchange exploded' });
+  });
+
   it('broadcasts to explicit targets with a broadcast id', async () => {
     addTerminal('peer1', 'Peer One');
     addTerminal('peer2', 'Peer Two');
@@ -642,6 +657,15 @@ describe('Broker (unit, stub deps)', () => {
     expect(res).toEqual({ ok: false, error: 'boom' });
   });
 
+  it('answers the socket when portal op=new throws outside the internal try', async () => {
+    // The `new` branch runs before handlePortal's internal try; a throw there
+    // must be answered by the dispatch catch, not leaked as an unhandled
+    // rejection.
+    portals.create.mockImplementationOnce(() => { throw new Error('portal factory exploded'); });
+    const res = await rpc(sock, { cmd: 'portal', from: 'lead', op: 'new', target: '', arg: 'https://x' });
+    expect(res).toEqual({ ok: false, error: 'portal factory exploded' });
+  });
+
   it('portal read ops return their payloads', async () => {
     addPortal('p1', 'Portal One');
     const js = await rpc(sock, { cmd: 'portal', from: 'lead', op: 'js', target: 'p1', arg: '1+1' });
diff --git a/src/main/broker.ts b/src/main/broker.ts
index c92d033..8ffc4a5 100644
--- a/src/main/broker.ts
+++ b/src/main/broker.ts
@@ -108,7 +108,11 @@ export class Broker {
     }
     switch (req.cmd) {
       case 'ask':
-        void this.handleAsk(socket, req);
+        // The internal Promise.all can reject (e.g. a PTY dies mid-ask);
+        // never leak that as an unhandled rejection — answer the terminal.
+        void this.handleAsk(socket, req).catch((err: unknown) => {
+          this.respond(socket, { ok: false, error: (err as Error).message });
+        });
         return;
       case 'check':
         return this.handleCheck(socket, req.from, req.target);
@@ -127,7 +131,11 @@ export class Broker {
           req.chain,
         );
       case 'portal':
-        void this.handlePortal(socket, req);
+        // Covers the residue outside handlePortal's internal try (op=new and
+        // the pre-try wiring); the internal try answers for its own ops.
+        void this.handlePortal(socket, req).catch((err: unknown) => {
+          this.respond(socket, { ok: false, error: (err as Error).message });
+        });
         return;
       case 'contract':
         return this.handleContract(socket, req);
diff --git a/src/main/ptyManager.test.ts b/src/main/ptyManager.test.ts
index 25d2cb7..2c4a621 100644
--- a/src/main/ptyManager.test.ts
+++ b/src/main/ptyManager.test.ts
@@ -1,9 +1,10 @@
-import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { describe, it, expect, beforeAll, afterAll, vi } from 'vitest';
 import * as fs from 'node:fs';
 import * as os from 'node:os';
 import * as path from 'node:path';
 import { GraphStore } from './graphStore';
 import { PtyManager } from './ptyManager';
+import * as processTree from './processTree';
 
 const wait = (ms: number) => new Promise((r) => setTimeout(r, ms));
 
@@ -101,3 +102,56 @@ describe('PtyManager spawn-time role ordering', () => {
     expect(text).toContain('Dogwalker role was updated');
   }, 10_000);
 });
+
+// ── safety net: the memory poller must never become an unhandled rejection
+// source. listProcesses() normally resolves [] on error, but a rejection
+// anywhere in checkMemory (e.g. a throwing process-tree implementation) must
+// be logged by the interval's defensive catch — never leak.
+describe('PtyManager memory poller safety net', () => {
+  let dir = '';
+  let graph: GraphStore;
+  let ptys: PtyManager;
+  let term = '';
+
+  const webContents = {
+    send: () => {},
+    isDestroyed: () => false,
+  } as unknown as ConstructorParameters<typeof PtyManager>[0];
+
+  beforeAll(() => {
+    dir = fs.mkdtempSync(path.join(os.tmpdir(), 'dw-pty-mem-'));
+    graph = new GraphStore();
+    ptys = new PtyManager(webContents, graph, { socketPath: dir, shimDir: dir });
+    term = ptys.spawn({
+      preset: 'shell', name: 'mem-term', stableId: 'mem-term',
+      cols: 80, rows: 24, workspaceId: 'mem', floorName: 'ground', cwd: dir,
+    }).id;
+  });
+
+  afterAll(async () => {
+    ptys.killAll();
+    await wait(200);
+    try {
+      fs.rmSync(dir, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 });
+    } catch {
+      /* best-effort cleanup */
+    }
+  });
+
+  it('logs instead of leaking a rejection when a memory poll fails', async () => {
+    ptys.setMemoryLimit(term, 256); // starts the 5s poller
+    const procSpy = vi.spyOn(processTree, 'listProcesses').mockRejectedValue(new Error('ps boom'));
+    const errSpy = vi.spyOn(console, 'error').mockImplementation(() => {});
+    try {
+      await wait(6_500); // one real poll cycle (5s interval)
+      expect(errSpy).toHaveBeenCalledWith(
+        expect.stringContaining('[dw] memory check failed'),
+        expect.any(Error),
+      );
+    } finally {
+      procSpy.mockRestore();
+      errSpy.mockRestore();
+      ptys.setMemoryLimit(term, 0); // stops the poller
+    }
+  }, 30_000);
+});
diff --git a/src/main/ptyManager.ts b/src/main/ptyManager.ts
index 2358c7e..43f3439 100644
--- a/src/main/ptyManager.ts
+++ b/src/main/ptyManager.ts
@@ -388,7 +388,14 @@ export class PtyManager {
   private syncMemoryPoller(): void {
     const wanted = [...this.entries.values()].some((e) => e.memoryLimitMB > 0);
     if (wanted && !this.memoryTimer) {
-      this.memoryTimer = setInterval(() => void this.checkMemory(), MEMORY_POLL_MS);
+      this.memoryTimer = setInterval(() => {
+        void this.checkMemory().catch((err: unknown) => {
+          // Defensive: the poller must never become an unhandled rejection
+          // source. Observability only — the limit enforcement stays in
+          // checkMemory's own paths.
+          console.error('[dw] memory check failed:', err);
+        });
+      }, MEMORY_POLL_MS);
     } else if (!wanted && this.memoryTimer) {
       clearInterval(this.memoryTimer);
       this.memoryTimer = null;
diff --git a/src/main/routineService.test.ts b/src/main/routineService.test.ts
index 5850949..5b55e7a 100644
--- a/src/main/routineService.test.ts
+++ b/src/main/routineService.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { describe, it, expect, beforeAll, afterAll, vi } from 'vitest';
 import * as fs from 'node:fs';
 import * as os from 'node:os';
 import * as path from 'node:path';
@@ -65,4 +65,27 @@ describe('RoutineService (integration, real PTY)', () => {
     expect(routines.list('rt').find((r) => r.id === routine.id)?.status).toBe('paused');
     routines.remove(routine.id);
   }, 30_000);
+
+  it('logs instead of leaking a rejection when a tick throws before its internal try', async () => {
+    // onUpdate fires before tick's internal try; a throw there rejects the
+    // tick. The interval's defensive catch must log it, never surface an
+    // unhandled rejection (which vitest would fail the suite on).
+    const boomTerm = ptys.spawn({ preset: 'shell', cols: 80, rows: 24, workspaceId: 'rt', stableId: 'boom-term', cwd: '', name: 'boom-term' }).id;
+    const errSpy = vi.spyOn(console, 'error').mockImplementation(() => {});
+    const throwing = new RoutineService(dir, ptys, () => { throw new Error('onUpdate boom'); });
+    try {
+      const routine = throwing.create('rt', {
+        name: 'boom', targetStableId: 'boom-term', prompt: 'echo X', intervalMs: 5_000,
+      });
+      await wait(6_500); // one real interval cycle (5s min)
+      expect(errSpy).toHaveBeenCalledWith(
+        expect.stringContaining(`[dw] routine ${routine.id} tick failed`),
+        expect.any(Error),
+      );
+    } finally {
+      throwing.disposeAll();
+      ptys.kill(boomTerm);
+      errSpy.mockRestore();
+    }
+  }, 30_000);
 });
diff --git a/src/main/routineService.ts b/src/main/routineService.ts
index 5b34815..63f7763 100644
--- a/src/main/routineService.ts
+++ b/src/main/routineService.ts
@@ -104,7 +104,14 @@ export class RoutineService {
     this.disarm(r.id);
     this.timers.set(
       r.id,
-      setInterval(() => void this.tick(r.id), r.intervalMs),
+      setInterval(() => {
+        void this.tick(r.id).catch((err: unknown) => {
+          // Defensive: tick's internal try/finally covers the run itself;
+          // this only catches pre-try throws so the scheduler never leaks an
+          // unhandled rejection every interval. Observability only.
+          console.error(`[dw] routine ${r.id} tick failed:`, err);
+        });
+      }, r.intervalMs),
     );
   }
 
diff --git a/src/renderer.tsx b/src/renderer.tsx
index 821bd40..f394c0b 100644
--- a/src/renderer.tsx
+++ b/src/renderer.tsx
@@ -4,6 +4,13 @@ import '@xterm/xterm/css/xterm.css';
 import './index.css';
 import { App } from './app/App';
 
+// Safety net — observability only, never recovery: anything that still escapes
+// the local catches lands here as a structured log (mirrored to the main
+// process stdout). It does not replace per-call `.catch` handling.
+window.addEventListener('unhandledrejection', (event) => {
+  console.error('[dw] unhandledrejection:', event.reason);
+});
+
 const container = document.getElementById('root');
 if (!container) throw new Error('missing #root');
 createRoot(container).render(<App />);