## Evidence

### Issue #74404 — Gateway CPU-Saturated, Agents Stop Responding
- **Severity:** HIGH
- **Status:** CLOSED in 2026.5.2 stable (supposedly fixed)
- **Current version:** 2026.5.12-beta.1 (AFTER the stable fix release)
- **Key metric - Event Loop Delays:**
  - 21:06: 28,145ms delay
  - 21:10: 52,126ms delay
  - 21:17: 120,807ms delay (2 minutes)
  - 21:22: 145,221ms delay
  - 21:25: 196,270ms delay
  - 21:29: 211,730ms delay (3.5 minutes)
  - 21:34: 277,594ms delay (4.6 minutes)
  - 21:40: 346,821ms delay (5.8 minutes)
  - **21:47: 420,420ms delay (7 minutes)** ← User reported Marcus stuck here
  - 21:53: stability check FAILED with 10s timeout

### Gateway Response Times (sessions.list)
- 21:38: **1,816,340ms** (30 minutes) for a single sessions.list call
- 21:53: **2,731,729ms** (45 minutes) for sessions.list

### Telegram Polling Stalls (multiple)

21:19:50 - Polling stall detected (142.88s stuck)
21:25:51 - Polling stall detected (206.45s stuck)
21:34:21 - Polling stall detected (287.77s stuck)


### Gateway Stability Check

21:53:35 - Gateway stability failed: GatewayTransportError: gateway timeout after 10000ms


---

## System Info

| Component | Value |
|-----------|-------|
| OS | Linux, NVMe disk |
| Node.js | v24.14.1 |
| Memory Total | 31 GiB |
| Memory Available | 26 GiB |
| Disk Usage | 70% used (68 GiB available) |
| Gateway | loopback (127.0.0.1:18789) |
| Service | systemd user (pid 1582, state active) |

---

## Analysis

The blocklist entry for #74404 states it was "fixed in 2026.5.2 stable". However:

1. **User is running 2026.5.12-beta.1** - a beta version released AFTER the stable fix
2. **The fix appears incomplete or regressed** - event loop delays are back to 400+ seconds
3. **Telegram polling is a major contributor** - getUpdates calls are timing out and blocking

This suggests either:
- The #74404 fix was incomplete
- A regression was introduced after 2026.5.2 stable
- The Telegram polling issue (#73432 - QMD Embed Timer) is exacerbating the problem

---

## Relevant Blocklist Entries

| Issue | Status | Relevance |
|-------|--------|-----------|
| #74404 | CLOSED (2026.5.2 stable) | SAME SYMPTOM - but fix regressed? |
| #73432 | OPEN | Telegram polling stalls |
| #75501 | OPEN | Too many open files (v4.29 regression) |

---

work=[active=agent:marcus:main(processing,q=1,age=186s) queued=agent:marcus:main(processing,q=1,age=186s)]

---

liveness warning: reasons=event_loop_utilization,cpu interval=567s
phase=channels.telegram.start-account
recentPhases=channels.telegram.runtime:0ms,channels.telegram.approval-bootstrap:0ms,
             channels.telegram.start-account:7332155ms,...

---

warn fetch-timeout {"timeoutMs":10000,"elapsedMs":430420,"timerDelayMs":420420,
                    "eventLoopDelayHint":"timer delayed 420420ms, likely event-loop starvation"}

---

const trackedPromise = Promise.resolve().then(() =>
  measureStartup(`channels.${channelId}.start-account`, () =>
    startAccount({ cfg, accountId: id, account, runtime, ... })
  )
);

---

async function fetchWithTimeout(url, init, timeoutMs, fetchFn = fetch) {
  const { signal, cleanup } = buildTimeoutAbortSignal({...});
  try {
    return await fetchFn(url, { ...init, signal });  // <-- BLOCKING
  } finally {
    cleanup();
  }
}

---

// Current (BLOCKING):
const trackedPromise = Promise.resolve().then(() =>
  measureStartup(`channels.${channelId}.start-account`, () =>
    startAccount({ cfg, accountId: id, account, runtime, ... })
  )
);

// Fixed (NON-BLOCKING):
// Run startAccount in a separate microtask to not block the gateway
const trackedPromise = Promise.resolve().then(async () => {
  // Don't await blocking operations in the gateway task queue
  if (channelId === 'telegram') {
    // Spawn as detached task
    setImmediate(() => {
      measureStartup(`channels.${channelId}.start-account`, () =>
        startAccount({ cfg, accountId: id, account, runtime, ... })
      );
    });
    return;
  }
  return measureStartup(`channels.${channelId}.start-account`, () =>
    startAccount({ cfg, accountId: id, account, runtime, ... })
  );
});

---

const circuitBreaker = {
  failures: 0,
  maxFailures: 3,
  resetTimeout: 30000, // 30 seconds

  async call(fn) {
    if (this.failures >= this.maxFailures) {
      throw new Error('Circuit breaker open - Telegram API unavailable');
    }
    try {
      return await fn();
    } catch (err) {
      this.failures++;
      if (this.failures >= this.maxFailures) {
        setTimeout(() => this.failures = 0, this.resetTimeout);
      }
      throw err;
    }
  }
};

// Usage:
meRes = await circuitBreaker.call(() =>
  fetchWithTimeout(`${base}/getMe`, {}, timeoutBudgetMs, fetcher)
);

---

const { Worker } = require('worker_threads');

async function startAccountInWorker(params) {
  return new Promise((resolve, reject) => {
    const worker = new Worker('./telegram-start-worker.js', {
      workerData: params
    });
    worker.on('message', resolve);
    worker.on('error', reject);
    worker.on('exit', (code) => {
      if (code !== 0) reject(new Error(`Worker exited with code ${code}`));
    });
  });
}

---

// Current: timeoutBudgetMs can be very large
meRes = await fetchWithTimeout(`${base}/getMe`, {}, timeoutBudgetMs, fetcher);

// Fixed: Cap at 5 seconds, fail fast
const TEELEGRAM_START_TIMEOUT = 5000; // 5 seconds max
meRes = await fetchWithTimeout(`${base}/getMe`, {}, TEELEGRAM_START_TIMEOUT, fetcher);