health monitor (ops-18/19): spend/disk/task-queue thresholds -> staff alerts, edge-triggered, opt-in

DECISIONS.md

@@ -60,6 +60,16 @@ Decisions inside the set architecture. D-NNN, never renumbered.
   broken classifier must never mute the bot; the budget gate already
   bounds spend. Its verdict gates BEFORE the main call, the
   envelope's answer_needed still gates after — two independent nets.
+- **D-021** — Health monitoring (FDB-012, SPEC-012 OPS-18/19): a
+  separate `monitor_loop` (own cadence, default 300 s) rather than
+  folding checks into the 60 s task loop — monitoring is coarse and
+  should not run every minute. Checks are edge-triggered (alert on the
+  rising edge, re-arm on recovery) so a standing condition never spams;
+  they reuse the existing rate-limited staff-alert path. Metrics are
+  the cheap, high-signal ones (spend vs budget, free disk, task-queue
+  depth); each is independently skippable when it has no data, so a
+  deployment without a budget or store still runs the others. Opt-in
+  (`enable-monitoring`) like every other operational rollout.
 - **D-020** — Web search via Exa (FDB-022, SPEC-015): a `web_search`
   tool alongside fetch_url/IGDB/codex/get_news, filling the "look it up
   on the open web" gap. Exa (not a raw search-engine scrape) because it

fjerkroa_bot/discord_bot.py

@@ -3,9 +3,11 @@ import asyncio
 import logging
 import random
 import re
+import shutil
 import sys
 import time
 from collections import deque
+from pathlib import Path
 from typing import Optional, Union
 
 import discord
@@ -16,6 +18,7 @@ from watchdog.events import FileSystemEventHandler
 from watchdog.observers import Observer
 
 from .ai_responder import AIMessage
+from .monitor import HealthMonitor
 from .openai_responder import OpenAIResponder
 from .tasks import TaskEngine
 
@@ -130,6 +133,15 @@ class FjerkroaBot(commands.Bot):
             observe=self.airesponder.observe_event,
         )
         self.loop.create_task(self.task_loop())
+        # Proactive health monitoring -> staff alerts (OPS-18/19)
+        self.health_monitor = HealthMonitor(
+            config_getter=lambda: self.config,
+            ledger=self.airesponder.ledger,
+            store=self.airesponder.store,
+            disk_free_mb=self._disk_free_mb,
+            alert=self.send_staff_alert,
+        )
+        self.loop.create_task(self.monitor_loop())
         logging.info("Task engine initialised.")
 
     async def task_loop(self):
@@ -140,6 +152,20 @@ class FjerkroaBot(commands.Bot):
             except Exception as err:
                 logging.warning(f"task tick failed: {repr(err)}")
 
+    def _disk_free_mb(self) -> float:
+        directory = Path(self.config.get("history-directory", ".")).expanduser()
+        target = directory if directory.exists() else Path.home()
+        return shutil.disk_usage(target).free / (1024 * 1024)
+
+    async def monitor_loop(self):
+        while True:
+            await asyncio.sleep(int(self.config.get("monitor-interval", 300)))
+            if self.health_monitor.enabled():
+                try:
+                    await self.health_monitor.tick()
+                except Exception as err:
+                    logging.warning(f"monitor tick failed: {repr(err)}")
+
     async def _execute_task(self, channel_name: str, prompt: str) -> None:
         """Run a due task through the normal responder path (TSK-02)."""
         channel = self.channel_by_name(channel_name, getattr(self, "chat_channel", None), no_ignore=True)

fjerkroa_bot/monitor.py

@@ -0,0 +1,82 @@
+"""Proactive health monitoring -> staff alerts (SPEC-012, FDB-012).
+
+A periodic check that watches daily spend against the budget, free disk,
+and task-queue depth, and posts a staff alert when a threshold is crossed
+— once per crossing, re-arming when the metric recovers, so a persistent
+condition never spams. Opt-in per deployment (`enable-monitoring`); it
+reuses the rate-limited staff-alert channel (OPS-07).
+"""
+
+import logging
+from typing import Any, Callable, Dict, Optional, Tuple
+
+# A check returns (metric-name, is-over-threshold, alert-message) or None when not applicable.
+Check = Optional[Tuple[str, bool, str]]
+
+
+class HealthMonitor:
+    def __init__(
+        self,
+        config_getter: Callable[[], Dict[str, Any]],
+        ledger: Any,
+        store: Any,
+        disk_free_mb: Callable[[], float],
+        alert: Callable[[str], Any],
+    ) -> None:
+        self._config = config_getter
+        self._ledger = ledger
+        self._store = store
+        self._disk_free_mb = disk_free_mb
+        self._alert = alert
+        self._armed: Dict[str, bool] = {}
+
+    def enabled(self) -> bool:
+        return bool(self._config().get("enable-monitoring", False))
+
+    def _check_spend(self) -> Check:
+        config = self._config()
+        if "daily-budget-usd" not in config:
+            return None
+        budget = float(config["daily-budget-usd"])
+        if budget <= 0:
+            return None
+        spent = float(self._ledger.spent_usd())
+        frac = spent / budget
+        threshold = float(config.get("monitor-spend-alert-frac", 0.8))
+        return ("spend", frac >= threshold, f"💸 Spend at ${spent:.2f} of ${budget:.2f} today ({frac:.0%}, alert ≥ {threshold:.0%}).")
+
+    def _check_disk(self) -> Check:
+        try:
+            free = float(self._disk_free_mb())
+        except Exception as err:
+            logging.debug(f"monitor: disk check failed: {err!r}")
+            return None
+        min_mb = float(self._config().get("monitor-disk-min-mb", 500))
+        return ("disk", free < min_mb, f"💾 Low disk: {free:.0f} MB free (alert < {min_mb:.0f} MB).")
+
+    def _check_queue(self) -> Check:
+        if self._store is None:
+            return None
+        try:
+            depth = len(self._store.tasks_open())
+        except Exception as err:
+            logging.debug(f"monitor: queue check failed: {err!r}")
+            return None
+        limit = int(self._config().get("monitor-taskqueue-max", 20))
+        return ("task-queue", depth >= limit, f"🗒️ Task queue deep: {depth} open (alert ≥ {limit}).")
+
+    async def tick(self) -> None:
+        """Evaluate every check; alert on a rising edge only (OPS-18/19)."""
+        for check in (self._check_spend(), self._check_disk(), self._check_queue()):
+            if check is None:
+                continue
+            metric, over, message = check
+            await self._fire(metric, over, message)
+
+    async def _fire(self, metric: str, over: bool, message: str) -> None:
+        was_over = self._armed.get(metric, False)
+        if over and not was_over:
+            self._armed[metric] = True
+            await self._alert(message)
+        elif not over and was_over:
+            self._armed[metric] = False  # recovered — re-arm silently for the next crossing

specs/SPEC-012-ops.md

@@ -30,3 +30,23 @@ The responder counts consecutive OpenAI request failures; at
 alert (rate-limited like all staff alerts) so a silently-broken bot
 (cf. the gpt-5.6 tools/reasoning incident) surfaces within minutes
 instead of hours. A success resets the counter.
+
+### OPS-18 — Health monitor watches spend, disk, task-queue (coverage: test)
+
+When `enable-monitoring` is true, a loop wakes every `monitor-interval`
+(default 300 s) and checks three thresholds, alerting the staff channel
+when one is crossed: daily spend at or above `monitor-spend-alert-frac`
+(default 0.8) of `daily-budget-usd`; free disk below `monitor-disk-min-mb`
+(default 500 MB); open task-queue depth at or above `monitor-taskqueue-max`
+(default 20). A check with no data to evaluate (no budget set, no store,
+a failed disk read) is skipped, never fatal. With the flag off the loop
+does nothing.
+
+### OPS-19 — Alerts fire once per crossing and re-arm on recovery (coverage: test)
+
+Each metric alerts only on the rising edge — the first tick that finds
+it over its threshold — and stays silent while it remains over, so a
+persistent condition does not repeat every interval. When the metric
+falls back below the threshold the alert re-arms silently, ready to fire
+again on the next crossing. All alerts still pass through the
+rate-limited staff-alert path (OPS-07).

tests/test_spec_monitor.py

@@ -0,0 +1,106 @@
+"""Unit coverage for SPEC-012 health monitoring (OPS-18/19)."""
+
+import unittest
+from unittest.mock import AsyncMock
+
+from fjerkroa_bot.monitor import HealthMonitor
+
+
+class FakeLedger:
+    def __init__(self, spent=0.0):
+        self._spent = spent
+
+    def spent_usd(self):
+        return self._spent
+
+
+class FakeStore:
+    def __init__(self, open_tasks=0):
+        self._n = open_tasks
+
+    def tasks_open(self):
+        return list(range(self._n))
+
+
+def _monitor(cfg, ledger=None, store=None, disk=1000.0):
+    alert = AsyncMock()
+    monitor = HealthMonitor(lambda: cfg, ledger or FakeLedger(), store, lambda: disk, alert)
+    return monitor, alert
+
+
+class TestEnabled(unittest.TestCase):
+    def test_opt_in(self):
+        """OPS-18: monitoring is opt-in via enable-monitoring."""
+        self.assertFalse(_monitor({})[0].enabled())
+        self.assertTrue(_monitor({"enable-monitoring": True})[0].enabled())
+
+
+class TestChecks(unittest.IsolatedAsyncioTestCase):
+    async def test_spend_over_threshold_alerts(self):
+        """OPS-18: spend at/above frac*budget alerts."""
+        monitor, alert = _monitor({"daily-budget-usd": 2.0, "monitor-spend-alert-frac": 0.8}, ledger=FakeLedger(1.8))
+        await monitor.tick()
+        alert.assert_awaited_once()
+        self.assertIn("Spend", alert.await_args.args[0])
+
+    async def test_spend_under_threshold_silent(self):
+        """OPS-18: spend below threshold stays silent."""
+        monitor, alert = _monitor({"daily-budget-usd": 2.0}, ledger=FakeLedger(0.5))
+        await monitor.tick()
+        alert.assert_not_awaited()
+
+    async def test_no_budget_skips_spend(self):
+        """OPS-18: no budget configured -> spend check skipped, never fatal."""
+        monitor, alert = _monitor({"enable-monitoring": True}, ledger=FakeLedger(99))
+        await monitor.tick()
+        alert.assert_not_awaited()
+
+    async def test_low_disk_alerts(self):
+        """OPS-18: free disk below the floor alerts."""
+        monitor, alert = _monitor({"monitor-disk-min-mb": 500}, disk=100.0)
+        await monitor.tick()
+        self.assertTrue(any("Low disk" in call.args[0] for call in alert.await_args_list))
+
+    async def test_disk_read_failure_skipped(self):
+        """OPS-18: a failing disk read is skipped, not fatal."""
+
+        def boom():
+            raise OSError("nope")
+
+        alert = AsyncMock()
+        monitor = HealthMonitor(lambda: {}, FakeLedger(), None, boom, alert)
+        await monitor.tick()
+        alert.assert_not_awaited()
+
+    async def test_deep_queue_alerts(self):
+        """OPS-18: task-queue depth at/above max alerts."""
+        monitor, alert = _monitor({"monitor-taskqueue-max": 3}, store=FakeStore(5), disk=9999.0)
+        await monitor.tick()
+        self.assertTrue(any("Task queue" in call.args[0] for call in alert.await_args_list))
+
+    async def test_no_store_skips_queue(self):
+        """OPS-18: no store -> queue check skipped."""
+        monitor, alert = _monitor({"monitor-taskqueue-max": 1}, store=None, disk=9999.0)
+        await monitor.tick()
+        alert.assert_not_awaited()
+
+
+class TestEdgeArming(unittest.IsolatedAsyncioTestCase):
+    async def test_fires_once_per_crossing(self):
+        """OPS-19: a persistent over-threshold condition alerts once, not every tick."""
+        monitor, alert = _monitor({"daily-budget-usd": 2.0}, ledger=FakeLedger(1.9))
+        await monitor.tick()
+        await monitor.tick()
+        await monitor.tick()
+        self.assertEqual(alert.await_count, 1)
+
+    async def test_rearms_on_recovery(self):
+        """OPS-19: recovery re-arms silently; the next crossing alerts again."""
+        ledger = FakeLedger(1.9)
+        monitor, alert = _monitor({"daily-budget-usd": 2.0}, ledger=ledger, disk=9999.0)
+        await monitor.tick()  # over -> alert (1)
+        ledger._spent = 0.5
+        await monitor.tick()  # recovered -> silent, re-arm
+        ledger._spent = 1.95
+        await monitor.tick()  # over again -> alert (2)
+        self.assertEqual(alert.await_count, 2)