refactor web pagination and add partitioned events, flap/timeout showcase agents

deploy/docker-compose.showcase.yml

@@ -9,7 +9,7 @@ services:
       MONLET_STALE_AFTER_SEC: "20"
       MONLET_DEAD_AFTER_SEC: "40"
       MONLET_DETECTOR_TICK_SEC: "5"
-      MONLET_EVENTS_RETENTION_MAX_ROWS: "5000"
+      MONLET_EVENTS_RETENTION_MONTHS: "1"
       MONLET_OUTBOX_RETENTION_MAX_ROWS: "1000"
       MONLET_NOTIFIER_DEBUG_ENABLED: "true"
       MONLET_NOTIFIER_WEBHOOK_ENABLED: "true"
@@ -56,6 +56,32 @@ services:
       agent-mixed:
         condition: service_started
 
+  agent-flap:
+    image: monlet-showcase-agent
+    environment:
+      MONLET_CONFIG: /etc/monlet/agent.toml
+    volumes:
+      - ./showcase/agents/flap.toml:/etc/monlet/agent.toml:ro
+      - ./showcase/checks:/opt/monlet/checks:ro
+    depends_on:
+      server:
+        condition: service_healthy
+      agent-mixed:
+        condition: service_started
+
+  agent-timeout:
+    image: monlet-showcase-agent
+    environment:
+      MONLET_CONFIG: /etc/monlet/agent.toml
+    volumes:
+      - ./showcase/agents/timeout.toml:/etc/monlet/agent.toml:ro
+      - ./showcase/checks:/opt/monlet/checks:ro
+    depends_on:
+      server:
+        condition: service_healthy
+      agent-mixed:
+        condition: service_started
+
   agent-prometheus-owned:
     image: monlet-showcase-agent
     environment:

deploy/showcase/agents/flap.toml

@@ -0,0 +1,25 @@
+hostname = "agent-flap"
+state_dir = "/var/lib/monlet-agent"
+
+[labels]
+scenario = "flapping"
+role = "showcase"
+
+[server]
+enabled = true
+url = "http://server:8000"
+token = "monlet-dev-token"
+heartbeat_interval = "5s"
+batch_interval = "3s"
+
+[metrics]
+enabled = false
+listen = "127.0.0.1:9465"
+
+[[checks]]
+id = "flap"
+name = "Flapping check (oscillates ok/critical)"
+command = "/opt/monlet/checks/flap.sh"
+interval = "10s"
+timeout = "3s"
+dedupe_key = "agent-flap:flap"

deploy/showcase/agents/timeout.toml

@@ -0,0 +1,33 @@
+hostname = "agent-timeout"
+state_dir = "/var/lib/monlet-agent"
+
+[labels]
+scenario = "timeout"
+role = "showcase"
+
+[server]
+enabled = true
+url = "http://server:8000"
+token = "monlet-dev-token"
+heartbeat_interval = "5s"
+batch_interval = "3s"
+
+[metrics]
+enabled = false
+listen = "127.0.0.1:9465"
+
+[[checks]]
+id = "ok_probe"
+name = "Healthy probe"
+command = "/opt/monlet/checks/exit_0.sh"
+interval = "10s"
+timeout = "3s"
+dedupe_key = "agent-timeout:ok_probe"
+
+[[checks]]
+id = "slow_probe"
+name = "Probe that exceeds the timeout"
+command = "/opt/monlet/checks/sleep_long.sh"
+interval = "10s"
+timeout = "2s"
+dedupe_key = "agent-timeout:slow_probe"

deploy/showcase/checks/flap.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+# Alternates between ok and critical every ~30 seconds to demonstrate flapping.
+slot=$(( $(date +%s) / 30 % 2 ))
+if [ "$slot" -eq 0 ]; then
+  echo "critical: flap window down"
+  exit 2
+fi
+echo "ok: flap window up"
+exit 0

deploy/showcase/checks/sleep_long.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+# Sleeps longer than the configured timeout to demonstrate timeout handling.
+sleep 30
+echo "should never reach here"
+exit 0

server/.env.example

@@ -7,7 +7,7 @@ MONLET_STALE_AFTER_SEC=90
 MONLET_DEAD_AFTER_SEC=300
 MONLET_DETECTOR_TICK_SEC=15
 MONLET_ENABLE_DETECTOR=true
-MONLET_EVENTS_RETENTION_MAX_ROWS=100000
+MONLET_EVENTS_RETENTION_MONTHS=36
 MONLET_OUTBOX_RETENTION_MAX_ROWS=50000
 
 MONLET_ENABLE_NOTIFIER_WORKER=true

server/README.md

@@ -39,7 +39,10 @@ UV_PROJECT_ENVIRONMENT=.venv UV_CACHE_DIR=../.cache/uv uv run fastapi dev monlet
 | `MONLET_DEAD_AFTER_SEC` | `300` | Dead threshold |
 | `MONLET_DETECTOR_TICK_SEC` | `15` | Detector tick |
 | `MONLET_ENABLE_DETECTOR` | `true` | Toggle detector task |
-| `MONLET_EVENTS_RETENTION_MAX_ROWS` | `100000` | Maximum retained check-result events; `0` disables pruning |
+| `MONLET_EVENTS_RETENTION_MONTHS` | `36` | Months of `events` partitions to keep; `0` disables drop |
+| `MONLET_EVENTS_FUTURE_PARTITIONS` | `3` | Future month partitions to pre-create |
+| `MONLET_EVENT_DEDUP_RETENTION_DAYS` | `30` | Idempotency window for `event_id` |
+| `MONLET_PARTITION_MAINTENANCE_INTERVAL_SEC` | `3600` | Partition create/drop worker interval |
 | `MONLET_OUTBOX_RETENTION_MAX_ROWS` | `50000` | Maximum retained terminal outbox rows; `0` disables pruning |
 | `MONLET_ENABLE_NOTIFIER_WORKER` | `true` | Toggle outbox worker |
 | `MONLET_NOTIFIER_TICK_SEC` | `5` | Worker poll interval |

server/alembic/versions/0001_baseline.py

@@ -50,10 +50,12 @@ def upgrade() -> None:
     )
     op.execute("CREATE INDEX checks_status_idx ON checks (status);")
 
+    # events: partitioned by RANGE(received_at). Partition key is part of PK per Postgres.
+    # Global idempotency by event_id is enforced via event_ingest_dedup, not this table.
     op.execute(
         """
         CREATE TABLE events (
-            event_id            UUID PRIMARY KEY,
+            event_id            UUID NOT NULL,
             agent_id            TEXT NOT NULL,
             check_id            TEXT NOT NULL,
             observed_at         TIMESTAMPTZ NOT NULL,
@@ -64,14 +66,30 @@ def upgrade() -> None:
             output              TEXT,
             output_truncated    BOOLEAN NOT NULL DEFAULT FALSE,
             notifications_enabled BOOLEAN NOT NULL DEFAULT TRUE,
-            incident_key        TEXT NOT NULL
-        );
+            incident_key        TEXT NOT NULL,
+            PRIMARY KEY (event_id, received_at)
+        ) PARTITION BY RANGE (received_at);
         """
     )
     op.execute(
         "CREATE INDEX events_agent_check_observed_idx ON events (agent_id, check_id, observed_at DESC);"
     )
     op.execute("CREATE INDEX events_observed_at_idx ON events (observed_at DESC);")
+    op.execute("CREATE INDEX events_received_at_idx ON events (received_at DESC);")
+
+    # Global idempotency table: server enforces event_id uniqueness here, not on the
+    # partitioned events table. Pruned by retention TTL (event_dedup_retention_days).
+    op.execute(
+        """
+        CREATE TABLE event_ingest_dedup (
+            event_id     UUID PRIMARY KEY,
+            received_at  TIMESTAMPTZ NOT NULL DEFAULT now()
+        );
+        """
+    )
+    op.execute(
+        "CREATE INDEX event_ingest_dedup_received_at_idx ON event_ingest_dedup (received_at);"
+    )
 
     op.execute(
         """
@@ -119,6 +137,7 @@ def upgrade() -> None:
 def downgrade() -> None:
     op.execute("DROP TABLE IF EXISTS notification_outbox CASCADE;")
     op.execute("DROP TABLE IF EXISTS incidents CASCADE;")
+    op.execute("DROP TABLE IF EXISTS event_ingest_dedup CASCADE;")
     op.execute("DROP TABLE IF EXISTS events CASCADE;")
     op.execute("DROP TABLE IF EXISTS checks CASCADE;")
     op.execute("DROP TABLE IF EXISTS agents CASCADE;")

server/monlet_server/main.py

@@ -14,19 +14,43 @@ from .middleware.body_limit import BodyLimitMiddleware
 from .middleware.request_id import RequestIdMiddleware
 from .services.detector import run_detector
 from .services.notifier_worker import run_notifier_worker
+from .services.partitioning import ensure_event_partitions, run_partition_maintenance
 from .settings import get_settings
 
 log = get_logger("monlet.main")
 
 
+async def _ensure_partitions_with_retry(engine, attempts: int = 6, base_delay: float = 1.0) -> None:
+    last_exc: Exception | None = None
+    for i in range(attempts):
+        try:
+            await ensure_event_partitions(engine)
+            return
+        except Exception as exc:
+            last_exc = exc
+            log.warning("ensure_event_partitions_retry", attempt=i + 1, error=str(exc))
+            await asyncio.sleep(min(base_delay * (2**i), 10.0))
+    assert last_exc is not None
+    raise last_exc
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     s = get_settings()
     configure_logging(s.log_level)
-    get_engine()
+    engine = get_engine()
     sm = get_sessionmaker()
+    # Mandatory: current month partition must exist before accepting writes.
+    # Retry briefly so a transient DB unavailability at startup (compose race)
+    # doesn't crash-loop the server.
+    await _ensure_partitions_with_retry(engine)
     stop_event = asyncio.Event()
     tasks: list[asyncio.Task] = []
+    # Partition maintenance is independent of detector — must run even when detector is off,
+    # otherwise events_future_partitions runs out and ingest fails.
+    tasks.append(
+        asyncio.create_task(run_partition_maintenance(sm, stop_event), name="partition_maintenance")
+    )
     if s.enable_detector:
         tasks.append(asyncio.create_task(run_detector(sm, stop_event), name="detector"))
     if s.enable_notifier_worker:

server/monlet_server/models.py

@@ -85,10 +85,11 @@ class Check(Base):
 class Event(Base):
     __tablename__ = "events"
 
-    event_id: Mapped[UUID] = mapped_column(_uuid(), primary_key=True)
+    event_id: Mapped[UUID] = mapped_column(_uuid(), nullable=False)
     agent_id: Mapped[str] = mapped_column(Text, nullable=False)
     check_id: Mapped[str] = mapped_column(Text, nullable=False)
     observed_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    # Partition key (RANGE) on Postgres; composite PK = (event_id, received_at).
     received_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )
@@ -103,6 +104,7 @@ class Event(Base):
     incident_key: Mapped[str] = mapped_column(Text, nullable=False)
 
     __table_args__ = (
+        PrimaryKeyConstraint("event_id", "received_at", name="events_pkey"),
         CheckConstraint(
             "status IN ('ok','warning','critical','unknown')", name="events_status_chk"
         ),
@@ -114,9 +116,21 @@ class Event(Base):
             text("observed_at DESC"),
         ),
         Index("events_observed_at_idx", text("observed_at DESC")),
+        Index("events_received_at_idx", text("received_at DESC")),
     )
 
 
+class EventIngestDedup(Base):
+    __tablename__ = "event_ingest_dedup"
+
+    event_id: Mapped[UUID] = mapped_column(_uuid(), primary_key=True)
+    received_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
+
+    __table_args__ = (Index("event_ingest_dedup_received_at_idx", "received_at"),)
+
+
 class Incident(Base):
     __tablename__ = "incidents"
 

server/monlet_server/services/detector.py

@@ -1,6 +1,6 @@
 import asyncio
 from datetime import UTC, datetime, timedelta
-from uuid import uuid4
+from uuid import UUID, uuid4, uuid7
 
 from sqlalchemy import delete, func, select, text
 from sqlalchemy.dialects.postgresql import insert as pg_insert
@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import async_sessionmaker
 
 from .. import metrics
 from ..logging_config import get_logger
-from ..models import Agent, Event, Incident, NotificationOutbox
+from ..models import Agent, Check, Event, EventIngestDedup, Incident, NotificationOutbox
 from ..settings import get_settings
 
 log = get_logger("monlet.detector")
@@ -25,6 +25,10 @@ def _liveness_severity(status: str) -> str:
     return "critical" if status == "dead" else "warning"
 
 
+_LIVENESS_CHECK_STATUS = {"alive": "ok", "stale": "warning", "dead": "critical"}
+_LIVENESS_EXIT_CODE = {"ok": 0, "warning": 1, "critical": 2}
+
+
 async def _enqueue_liveness_outbox(
     session,
     incident: Incident,
@@ -68,7 +72,9 @@ async def _enqueue_liveness_outbox(
         )
 
 
-async def _open_liveness_incident(session, agent: Agent, status: str, now: datetime) -> None:
+async def _open_liveness_incident(
+    session, agent: Agent, status: str, now: datetime, event_id: UUID
+) -> None:
     severity = _liveness_severity(status)
     summary = f"agent is {status}"
     incident_key = _liveness_key(agent.agent_id)
@@ -84,7 +90,7 @@ async def _open_liveness_incident(session, agent: Agent, status: str, now: datet
             severity=severity,
             opened_at=now,
             summary=summary,
-            last_event_id=uuid4(),
+            last_event_id=event_id,
         )
         .on_conflict_do_nothing(
             index_elements=[Incident.incident_key],
@@ -115,13 +121,13 @@ async def _open_liveness_incident(session, agent: Agent, status: str, now: datet
     if status == "dead" and inc.severity != "critical":
         inc.severity = "critical"
         inc.summary = summary
-        inc.last_event_id = uuid4()
+        inc.last_event_id = event_id
         await _enqueue_liveness_outbox(
             session, inc, "firing", agent, status, now, summary=summary, severity="critical"
         )
 
 
-async def _resolve_liveness_incident(session, agent: Agent, now: datetime) -> None:
+async def _resolve_liveness_incident(session, agent: Agent, now: datetime, event_id: UUID) -> None:
     inc = (
         await session.execute(
             select(Incident).where(
@@ -134,7 +140,7 @@ async def _resolve_liveness_incident(session, agent: Agent, now: datetime) -> No
         return
     inc.state = "resolved"
     inc.resolved_at = now
-    inc.last_event_id = uuid4()
+    inc.last_event_id = event_id
     metrics.incidents_resolved_total.inc()
     await _enqueue_liveness_outbox(
         session,
@@ -148,15 +154,83 @@ async def _resolve_liveness_incident(session, agent: Agent, now: datetime) -> No
     )
 
 
+async def _apply_liveness(session, agent: Agent, next_status: str, now: datetime) -> None:
+    """Server-owned liveness check: maintain Check + Event-on-transition + Incident lifecycle."""
+    liveness_status = _LIVENESS_CHECK_STATUS[next_status]
+    exit_code = _LIVENESS_EXIT_CODE[liveness_status]
+    summary = f"agent is {next_status}"
+    incident_key = _liveness_key(agent.agent_id)
+
+    cur = (
+        await session.execute(
+            select(Check).where(
+                Check.agent_id == agent.agent_id, Check.check_id == LIVENESS_CHECK_ID
+            )
+        )
+    ).scalar_one_or_none()
+    changed = cur is None or cur.status != liveness_status
+
+    # Liveness events flow through /events/query which validates event_id as UUIDv7.
+    event_id = cur.last_event_id if cur and not changed else uuid7()
+    if changed:
+        session.add(
+            Event(
+                event_id=event_id,
+                agent_id=agent.agent_id,
+                check_id=LIVENESS_CHECK_ID,
+                observed_at=now,
+                status=liveness_status,
+                exit_code=exit_code,
+                duration_ms=0,
+                output=summary,
+                output_truncated=False,
+                notifications_enabled=True,
+                incident_key=incident_key,
+            )
+        )
+
+    if cur is None:
+        session.add(
+            Check(
+                agent_id=agent.agent_id,
+                check_id=LIVENESS_CHECK_ID,
+                status=liveness_status,
+                exit_code=exit_code,
+                last_observed_at=now,
+                last_event_id=event_id,
+                incident_key=incident_key,
+                summary=summary,
+            )
+        )
+    else:
+        cur.last_observed_at = now
+        cur.summary = summary
+        if changed:
+            cur.status = liveness_status
+            cur.exit_code = exit_code
+            cur.last_event_id = event_id
+            cur.incident_key = incident_key
+
+    if next_status in ("stale", "dead"):
+        await _open_liveness_incident(session, agent, next_status, now, event_id)
+    else:
+        await _resolve_liveness_incident(session, agent, now, event_id)
+
+
 async def _prune_history(session) -> None:
     s = get_settings()
-    if s.events_retention_max_rows > 0:
-        keep_events = (
-            select(Event.event_id)
-            .order_by(Event.received_at.desc(), Event.event_id.desc())
-            .limit(s.events_retention_max_rows)
+    if s.event_dedup_retention_days > 0:
+        cutoff = datetime.now(UTC) - timedelta(days=s.event_dedup_retention_days)
+        batch = max(s.event_dedup_prune_batch_size, 1)
+        # Bounded DELETE: keep each tick's prune transaction short to avoid bloat and
+        # long-running locks on a large dedup table.
+        sub = (
+            select(EventIngestDedup.event_id)
+            .where(EventIngestDedup.received_at < cutoff)
+            .limit(batch)
+            .scalar_subquery()
         )
-        await session.execute(delete(Event).where(Event.event_id.not_in(keep_events)))
+        await session.execute(delete(EventIngestDedup).where(EventIngestDedup.event_id.in_(sub)))
 
     if s.outbox_retention_max_rows > 0:
         keep_outbox = (
@@ -188,10 +262,7 @@ async def _tick(sm: async_sessionmaker) -> None:
                 next_status = "alive"
             if agent.status != next_status:
                 agent.status = next_status
-            if next_status in ("stale", "dead"):
-                await _open_liveness_incident(session, agent, next_status, now)
-            else:
-                await _resolve_liveness_incident(session, agent, now)
+            await _apply_liveness(session, agent, next_status, now)
         await _prune_history(session)
         await session.commit()
 

server/monlet_server/services/ingestion.py

@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from .. import metrics
 from ..logging_config import get_logger
-from ..models import Agent, Check, Event, Incident, NotificationOutbox
+from ..models import Agent, Check, Event, EventIngestDedup, Incident, NotificationOutbox
 from ..redaction import redact
 from ..schemas import CheckResultEvent, HeartbeatRequest
 from ..settings import get_settings
@@ -155,26 +155,45 @@ async def ingest_event(
     agent_id: str,
     ev: CheckResultEvent,
 ) -> bool:
-    """Return True if a new change row was written, False if not (duplicate/unchanged/late)."""
+    """Return True if a new change row was written, False if not (duplicate/unchanged/late).
+
+    Idempotency is enforced first via the standalone event_ingest_dedup table — a
+    duplicate event_id never touches checks/incidents/outbox/events. The full pipeline
+    (dedup + events + check + incident + outbox) commits as a single transaction by
+    the caller, so a partial failure cannot leave a dedup row without its side-effects.
+    """
     observed = to_utc(ev.observed_at)
     output = redact(ev.output)
     check_summary = (output or "")[:200] if output else None
     incident_key = _incident_key(agent_id, ev)
+    event_uuid = UUID(ev.event_id)
 
+    # Order matters: late check before dedup insert so that repeated late events stay
+    # observable as `late`, not silently collapsed into `deduplicated`.
     chk_res = await session.execute(
         select(Check).where(Check.agent_id == agent_id, Check.check_id == ev.check_id)
     )
     cur = chk_res.scalar_one_or_none()
     is_late = cur is not None and cur.last_observed_at > observed
-    changed = cur is None or cur.status != ev.status or cur.exit_code != ev.exit_code
-
     if is_late:
         metrics.events_total.labels(result="late").inc()
         return False
 
+    dedup_stmt = (
+        pg_insert(EventIngestDedup)
+        .values(event_id=event_uuid, received_at=datetime.now(UTC))
+        .on_conflict_do_nothing(index_elements=[EventIngestDedup.event_id])
+        .returning(EventIngestDedup.event_id)
+    )
+    if (await session.execute(dedup_stmt)).scalar_one_or_none() is None:
+        metrics.events_total.labels(result="deduplicated").inc()
+        return False
+
+    changed = cur is None or cur.status != ev.status or cur.exit_code != ev.exit_code
+
     if changed:
         stmt = pg_insert(Event).values(
-            event_id=UUID(ev.event_id),
+            event_id=event_uuid,
             agent_id=agent_id,
             check_id=ev.check_id,
             observed_at=observed,
@@ -186,14 +205,7 @@ async def ingest_event(
             notifications_enabled=ev.notifications_enabled,
             incident_key=incident_key,
         )
-        stmt = stmt.on_conflict_do_nothing(index_elements=[Event.event_id]).returning(
-            Event.event_id
-        )
-        result = await session.execute(stmt)
-        inserted = result.scalar_one_or_none()
-        if inserted is None:
-            metrics.events_total.labels(result="deduplicated").inc()
-            return False
+        await session.execute(stmt)
         metrics.events_total.labels(result="accepted").inc()
     else:
         metrics.events_total.labels(result="unchanged").inc()
@@ -218,7 +230,7 @@ async def ingest_event(
         "summary": check_summary,
     }
     if changed:
-        update_set["last_event_id"] = UUID(ev.event_id)
+        update_set["last_event_id"] = event_uuid
         update_set["incident_key"] = incident_key
     chk_stmt = pg_insert(Check).values(**check_values)
     chk_stmt = chk_stmt.on_conflict_do_update(

server/monlet_server/services/partitioning.py

@@ -0,0 +1,143 @@
+"""Monthly partition maintenance for `events` (PARTITION BY RANGE(received_at)).
+
+Idempotent: creates current + N future month partitions and drops old ones beyond
+the retention window. Names are derived from year/month, so they cannot inject SQL.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from datetime import UTC, date, datetime
+
+from sqlalchemy import text
+from sqlalchemy.ext.asyncio import AsyncEngine, async_sessionmaker
+
+from ..logging_config import get_logger
+from ..settings import get_settings
+
+log = get_logger("monlet.partitioning")
+
+
+def _month_start(d: date) -> date:
+    return date(d.year, d.month, 1)
+
+
+def _next_month(d: date) -> date:
+    year = d.year + (1 if d.month == 12 else 0)
+    month = 1 if d.month == 12 else d.month + 1
+    return date(year, month, 1)
+
+
+def _shift_months(d: date, n: int) -> date:
+    y, m = d.year, d.month
+    total = y * 12 + (m - 1) + n
+    return date(total // 12, (total % 12) + 1, 1)
+
+
+def _partition_name(d: date) -> str:
+    return f"events_p{d.year:04d}_{d.month:02d}"
+
+
+async def ensure_event_partitions(engine_or_sm: AsyncEngine | async_sessionmaker) -> None:
+    """Create current + N future month partitions for events. Idempotent."""
+    s = get_settings()
+    today = _month_start(datetime.now(UTC).date())
+    months = [_shift_months(today, i) for i in range(0, max(s.events_future_partitions, 0) + 1)]
+
+    statements: list[str] = []
+    for start in months:
+        end = _next_month(start)
+        # Explicit UTC qualifier — Postgres otherwise interprets bare date literals via
+        # the session TimeZone, which would shift partition bounds on non-UTC servers.
+        statements.append(
+            f"CREATE TABLE IF NOT EXISTS {_partition_name(start)} "
+            f"PARTITION OF events FOR VALUES FROM ('{start.isoformat()} UTC') "
+            f"TO ('{end.isoformat()} UTC');"
+        )
+
+    async with _connect(engine_or_sm) as conn:
+        for stmt in statements:
+            await conn.execute(text(stmt))
+
+
+async def drop_old_event_partitions(engine_or_sm: AsyncEngine | async_sessionmaker) -> None:
+    """Drop month partitions older than events_retention_months.
+
+    Each DROP runs in its own transaction so the ACCESS EXCLUSIVE lock on parent
+    `events` is held only for one partition at a time and ingest is not blocked
+    by a long maintenance batch.
+    """
+    s = get_settings()
+    if s.events_retention_months <= 0:
+        return
+    cutoff = _shift_months(_month_start(datetime.now(UTC).date()), -s.events_retention_months)
+
+    engine = _resolve_engine(engine_or_sm)
+    async with engine.connect() as conn:
+        rows = (
+            await conn.execute(
+                text(
+                    """
+                    SELECT c.relname
+                    FROM pg_inherits i
+                    JOIN pg_class c ON c.oid = i.inhrelid
+                    JOIN pg_class p ON p.oid = i.inhparent
+                    WHERE p.relname = 'events'
+                    """
+                )
+            )
+        ).all()
+
+    to_drop: list[str] = []
+    for (name,) in rows:
+        if not name.startswith("events_p"):
+            continue
+        try:
+            y = int(name[8:12])
+            m = int(name[13:15])
+        except ValueError:
+            continue
+        if date(y, m, 1) < cutoff:
+            to_drop.append(name)
+
+    for name in to_drop:
+        async with engine.begin() as conn:
+            await conn.execute(text(f"DROP TABLE IF EXISTS {name};"))
+        log.info("event_partition_dropped", name=name)
+
+
+def _resolve_engine(engine_or_sm: AsyncEngine | async_sessionmaker) -> AsyncEngine:
+    if isinstance(engine_or_sm, async_sessionmaker):
+        return engine_or_sm.kw["bind"]
+    return engine_or_sm
+
+
+def _connect(engine_or_sm):
+    """Return an async ctx for a transactional connection from either engine or sessionmaker."""
+    return _resolve_engine(engine_or_sm).begin()
+
+
+async def run_partition_maintenance(sm: async_sessionmaker, stop_event: asyncio.Event) -> None:
+    """Independent worker — runs even when MONLET_ENABLE_DETECTOR=false."""
+    interval = max(get_settings().partition_maintenance_interval_sec, 60)
+    while not stop_event.is_set():
+        try:
+            await ensure_event_partitions(sm)
+            await drop_old_event_partitions(sm)
+        except Exception as exc:
+            log.warning("partition_maintenance_failed", error=str(exc))
+        try:
+            await asyncio.wait_for(stop_event.wait(), timeout=interval)
+        except TimeoutError:
+            continue
+
+
+# Re-export helpers for tests.
+__all__ = [
+    "run_partition_maintenance",
+    "ensure_event_partitions",
+    "drop_old_event_partitions",
+    "_partition_name",
+    "_shift_months",
+    "_month_start",
+]

server/monlet_server/settings.py

@@ -20,7 +20,11 @@ class Settings(BaseSettings):
     port: int = 8000
     enable_detector: bool = True
     enable_notifier_worker: bool = True
-    events_retention_max_rows: int = 20_000
+    events_retention_months: int = 36
+    events_future_partitions: int = 3
+    event_dedup_retention_days: int = 30
+    event_dedup_prune_batch_size: int = 5000
+    partition_maintenance_interval_sec: int = 3600
     outbox_retention_max_rows: int = 50_000
     notifier_tick_sec: int = 5
     notifier_batch_size: int = 20

server/tests/conftest.py

@@ -58,6 +58,20 @@ def _apply_migrations(database_url: str) -> Iterator[None]:
     cfg.set_main_option("script_location", os.path.join(SERVER_ROOT, "alembic"))
     cfg.set_main_option("sqlalchemy.url", get_settings().sync_database_url)
     command.upgrade(cfg, "head")
+
+    # Partitions for `events` are created at runtime, not by the migration.
+    async def _bootstrap() -> None:
+        from sqlalchemy.ext.asyncio import create_async_engine
+
+        from monlet_server.services.partitioning import ensure_event_partitions
+
+        eng = create_async_engine(database_url, future=True)
+        try:
+            await ensure_event_partitions(eng)
+        finally:
+            await eng.dispose()
+
+    asyncio.run(_bootstrap())
     yield
 
 
@@ -83,7 +97,7 @@ async def _truncate_tables(engine) -> AsyncIterator[None]:
     async with engine.begin() as conn:
         await conn.execute(
             text(
-                "TRUNCATE TABLE notification_outbox, incidents, events, checks, agents RESTART IDENTITY CASCADE"
+                "TRUNCATE TABLE notification_outbox, incidents, events, event_ingest_dedup, checks, agents RESTART IDENTITY CASCADE"
             )
         )
 

server/tests/test_constraints.py

@@ -9,26 +9,18 @@ from monlet_server.models import Incident
 
 
 @pytest.mark.asyncio
-async def test_event_id_conflict_do_nothing(engine):
+async def test_event_id_dedup_conflict_do_nothing(engine):
+    """Global idempotency is enforced via event_ingest_dedup, not the partitioned events table."""
     eid = str(uuid4())
     async with engine.begin() as conn:
         await conn.execute(
-            text(
-                "INSERT INTO agents (agent_id, hostname, features, status, last_seen_at) "
-                "VALUES ('a','h',jsonb_build_object('push', true, 'metrics', false),'alive', now())"
-            )
-        )
-        await conn.execute(
-            text(
-                "INSERT INTO events (event_id, agent_id, check_id, observed_at, status, exit_code, duration_ms, incident_key)"
-                " VALUES (:e,'a','c', now(),'ok',0,1,'a:c')"
-            ),
+            text("INSERT INTO event_ingest_dedup (event_id) VALUES (:e)"),
             {"e": eid},
         )
         r = await conn.execute(
             text(
-                "INSERT INTO events (event_id, agent_id, check_id, observed_at, status, exit_code, duration_ms, incident_key)"
-                " VALUES (:e,'a','c', now(),'ok',0,1,'a:c') ON CONFLICT (event_id) DO NOTHING RETURNING event_id"
+                "INSERT INTO event_ingest_dedup (event_id) VALUES (:e) "
+                "ON CONFLICT (event_id) DO NOTHING RETURNING event_id"
             ),
             {"e": eid},
         )

server/tests/test_detector.py

@@ -5,7 +5,7 @@ import pytest
 from sqlalchemy import func, select, update
 from sqlalchemy.ext.asyncio import async_sessionmaker
 
-from monlet_server.models import Agent, Event, Incident, NotificationOutbox
+from monlet_server.models import Agent, Check, Event, Incident, NotificationOutbox
 from monlet_server.services.detector import LIVENESS_CHECK_ID, _tick
 from monlet_server.settings import reset_settings_cache
 
@@ -82,22 +82,75 @@ async def test_detector_transitions(app_client, auth_headers, engine, session):
 
 
 @pytest.mark.asyncio
-async def test_detector_prunes_bounded_history(
-    app_client, auth_headers, engine, session, monkeypatch
-):
-    monkeypatch.setenv("MONLET_EVENTS_RETENTION_MAX_ROWS", "2")
+async def test_detector_owns_liveness_check_and_events(app_client, auth_headers, engine, session):
+    await app_client.post(
+        "/api/v1/heartbeat", json=make_heartbeat("agent-flap"), headers=auth_headers
+    )
+    sm = async_sessionmaker(engine, expire_on_commit=False)
+
+    # Tick 1: alive → Check exists with status=ok, one event.
+    await _tick(sm)
+    session.expire_all()
+    check = (
+        await session.execute(
+            select(Check).where(Check.agent_id == "agent-flap", Check.check_id == LIVENESS_CHECK_ID)
+        )
+    ).scalar_one()
+    assert check.status == "ok"
+    n_events = (
+        await session.execute(
+            select(func.count())
+            .select_from(Event)
+            .where(Event.agent_id == "agent-flap", Event.check_id == LIVENESS_CHECK_ID)
+        )
+    ).scalar_one()
+    assert n_events == 1
+
+    # Tick 2: still alive → no new event.
+    await _tick(sm)
+    session.expire_all()
+    n_events = (
+        await session.execute(
+            select(func.count())
+            .select_from(Event)
+            .where(Event.agent_id == "agent-flap", Event.check_id == LIVENESS_CHECK_ID)
+        )
+    ).scalar_one()
+    assert n_events == 1
+
+    # Push agent into dead → transition event written, Check updates.
+    await session.execute(
+        update(Agent)
+        .where(Agent.agent_id == "agent-flap")
+        .values(last_seen_at=datetime.now(UTC) - timedelta(minutes=10))
+    )
+    await session.commit()
+    await _tick(sm)
+    session.expire_all()
+    check = (
+        await session.execute(
+            select(Check).where(Check.agent_id == "agent-flap", Check.check_id == LIVENESS_CHECK_ID)
+        )
+    ).scalar_one()
+    assert check.status == "critical"
+    n_events = (
+        await session.execute(
+            select(func.count())
+            .select_from(Event)
+            .where(Event.agent_id == "agent-flap", Event.check_id == LIVENESS_CHECK_ID)
+        )
+    ).scalar_one()
+    assert n_events == 2
+
+
+@pytest.mark.asyncio
+async def test_detector_prunes_outbox(app_client, auth_headers, engine, session, monkeypatch):
     monkeypatch.setenv("MONLET_OUTBOX_RETENTION_MAX_ROWS", "2")
     reset_settings_cache()
     try:
         await app_client.post(
             "/api/v1/heartbeat", json=make_heartbeat("agent-prune"), headers=auth_headers
         )
-        events = [make_event(check_id="prune_check") for _ in range(5)]
-        await app_client.post(
-            "/api/v1/events",
-            json={"agent_id": "agent-prune", "events": events},
-            headers=auth_headers,
-        )
         critical = make_event(check_id="critical_prune", status="critical", exit_code=2)
         await app_client.post(
             "/api/v1/events",
@@ -129,7 +182,6 @@ async def test_detector_prunes_bounded_history(
         sm = async_sessionmaker(engine, expire_on_commit=False)
         await _tick(sm)
 
-        assert (await session.execute(select(func.count()).select_from(Event))).scalar_one() == 2
         terminal_outbox = (
             await session.execute(
                 select(func.count())

server/tests/test_partitioning.py

@@ -0,0 +1,125 @@
+from __future__ import annotations
+
+from datetime import UTC, date, datetime, timedelta
+
+import pytest
+from sqlalchemy import text
+
+from monlet_server.services.partitioning import (
+    _month_start,
+    _partition_name,
+    _shift_months,
+    drop_old_event_partitions,
+    ensure_event_partitions,
+)
+from monlet_server.settings import reset_settings_cache
+
+
+async def _partitions(engine) -> set[str]:
+    async with engine.begin() as conn:
+        rows = (
+            await conn.execute(
+                text(
+                    "SELECT c.relname FROM pg_inherits i "
+                    "JOIN pg_class c ON c.oid=i.inhrelid "
+                    "JOIN pg_class p ON p.oid=i.inhparent "
+                    "WHERE p.relname='events'"
+                )
+            )
+        ).all()
+    return {r[0] for r in rows}
+
+
+@pytest.mark.asyncio
+async def test_ensure_creates_current_and_future_partitions(engine, monkeypatch):
+    monkeypatch.setenv("MONLET_EVENTS_FUTURE_PARTITIONS", "2")
+    reset_settings_cache()
+    try:
+        await ensure_event_partitions(engine)
+        today = _month_start(datetime.now(UTC).date())
+        for i in range(0, 3):
+            assert _partition_name(_shift_months(today, i)) in await _partitions(engine)
+    finally:
+        reset_settings_cache()
+
+
+@pytest.mark.asyncio
+async def test_drop_old_partitions_uses_retention(engine, monkeypatch):
+    monkeypatch.setenv("MONLET_EVENTS_RETENTION_MONTHS", "1")
+    reset_settings_cache()
+    try:
+        # Create an old partition directly.
+        old = date(2020, 1, 1)
+        name = _partition_name(old)
+        end = _shift_months(old, 1)
+        async with engine.begin() as conn:
+            await conn.execute(
+                text(
+                    f"CREATE TABLE IF NOT EXISTS {name} PARTITION OF events "
+                    f"FOR VALUES FROM ('{old.isoformat()} UTC') TO ('{end.isoformat()} UTC');"
+                )
+            )
+        assert name in await _partitions(engine)
+        await drop_old_event_partitions(engine)
+        assert name not in await _partitions(engine)
+    finally:
+        reset_settings_cache()
+
+
+@pytest.mark.asyncio
+async def test_dedup_prevents_replay_via_ingest(app_client, auth_headers, session):
+    from sqlalchemy import func, select
+
+    from monlet_server.models import Event
+
+    from ._helpers import make_event, make_heartbeat
+
+    await app_client.post("/api/v1/heartbeat", json=make_heartbeat(), headers=auth_headers)
+    ev = make_event(status="critical", exit_code=2)
+
+    r1 = await app_client.post(
+        "/api/v1/events", json={"agent_id": "agent-1", "events": [ev]}, headers=auth_headers
+    )
+    assert r1.json() == {"accepted": 1, "deduplicated": 0}
+
+    # Replay the exact same event_id long after — dedup must block ingestion entirely,
+    # never touching checks/incidents/outbox/events.
+    r2 = await app_client.post(
+        "/api/v1/events", json={"agent_id": "agent-1", "events": [ev]}, headers=auth_headers
+    )
+    assert r2.json() == {"accepted": 0, "deduplicated": 1}
+
+    n = (await session.execute(select(func.count()).select_from(Event))).scalar_one()
+    assert n == 1
+
+
+@pytest.mark.asyncio
+async def test_late_dedup_does_not_keep_replay_doors_open(engine, monkeypatch):
+    """Dedup retention TTL must be at least documented agent spool window."""
+    from uuid import uuid4
+
+    from sqlalchemy import func, select
+    from sqlalchemy.ext.asyncio import async_sessionmaker
+
+    from monlet_server.models import EventIngestDedup
+    from monlet_server.services.detector import _prune_history
+
+    monkeypatch.setenv("MONLET_EVENT_DEDUP_RETENTION_DAYS", "1")
+    reset_settings_cache()
+    try:
+        sm = async_sessionmaker(engine, expire_on_commit=False)
+        async with sm() as s:
+            old = datetime.now(UTC) - timedelta(days=5)
+            s.add(EventIngestDedup(event_id=uuid4(), received_at=old))
+            s.add(EventIngestDedup(event_id=uuid4(), received_at=datetime.now(UTC)))
+            await s.commit()
+
+        async with sm() as s:
+            await _prune_history(s)
+            await s.commit()
+
+        async with sm() as s:
+            n = (await s.execute(select(func.count()).select_from(EventIngestDedup))).scalar_one()
+            assert n == 1
+    finally:
+        reset_settings_cache()

web/src/app/agents/[agent_id]/page.tsx

@@ -1,13 +1,14 @@
 import { AgentDetailBrowser } from "@/components/AgentDetailBrowser";
 import { ErrorPanel } from "@/components/DataPanel";
 import { ApiError, api } from "@/lib/api";
-import { withLivenessEvents } from "@/lib/check-groups";
 import { loadChecks } from "@/lib/loaders";
+import { normalizePageSize } from "@/lib/pagination";
 
 export const dynamic = "force-dynamic";
 
 type SortKey = "severity" | "check_id" | "last_seen";
 type TabKey = "checks" | "events";
+type EventsPage = Awaited<ReturnType<typeof api.queryEvents>>;
 
 function normalizeSort(sort?: string): SortKey {
   return sort === "check_id" || sort === "last_seen" ? sort : "severity";
@@ -21,22 +22,35 @@ export default async function AgentDetailPage({
   params,
   searchParams,
 }: {
-  params: Promise<{ agent_id: string }>;
-  searchParams: Promise<{ sort?: string; tab?: string }>;
+  params: Promise<{
+    agent_id: string;
+  }>;
+  searchParams: Promise<{
+    sort?: string;
+    tab?: string;
+    events_limit?: string;
+    cursor?: string;
+  }>;
 }) {
   const { agent_id } = await params;
   const sp = await searchParams;
   const sort = normalizeSort(sp.sort);
   const tab = normalizeTab(sp.tab);
+  const eventsLimit = normalizePageSize(sp.events_limit, 50);
+  const eventsCursor = sp.cursor;
 
-  let data;
+  let agent;
+  let checks;
+  let events: EventsPage = { items: [], next_cursor: null };
   try {
-    const [agent, checks, events] = await Promise.all([
-      api.getAgent(agent_id),
-      loadChecks(agent_id),
-      api.queryEvents({ agent_id, limit: 50 }).then((page) => page.items),
-    ]);
-    data = { agent, checks, events: withLivenessEvents([agent], events, { agentId: agent_id }) };
+    [agent, checks] = await Promise.all([api.getAgent(agent_id), loadChecks(agent_id)]);
+    if (tab === "events") {
+      events = await api.queryEvents({
+        agent_id,
+        limit: eventsLimit,
+        cursor: eventsCursor,
+      });
+    }
   } catch (e) {
     if (e instanceof ApiError && e.status === 404) {
       return <div className="text-sm text-neutral-400">Agent not found.</div>;
@@ -45,10 +59,13 @@ export default async function AgentDetailPage({
   }
   return (
     <AgentDetailBrowser
-      key={`${agent_id}:${tab}:${sort}`}
-      initialData={data}
+      key={`${agent_id}:${tab}:${sort}:${eventsLimit}:${eventsCursor ?? ""}`}
+      initialData={{ agent, checks }}
+      initialEvents={events}
       sort={sort}
       tab={tab}
+      eventsLimit={eventsLimit}
+      eventsCursor={eventsCursor}
     />
   );
 }

web/src/app/api/poll/agent/route.ts

@@ -1,7 +1,6 @@
 import { NextResponse } from "next/server";
 
 import { ApiError, api } from "@/lib/api";
-import { withLivenessEvents } from "@/lib/check-groups";
 import { loadChecks } from "@/lib/loaders";
 import { jsonError } from "@/lib/poll-response";
 
@@ -19,16 +18,8 @@ export async function GET(request: Request) {
   }
 
   try {
-    const [agent, checks, events] = await Promise.all([
-      api.getAgent(agentId),
-      loadChecks(agentId),
-      api.queryEvents({ agent_id: agentId, limit: 50 }).then((page) => page.items),
-    ]);
-    return NextResponse.json({
-      agent,
-      checks,
-      events: withLivenessEvents([agent], events, { agentId }),
-    });
+    const [agent, checks] = await Promise.all([api.getAgent(agentId), loadChecks(agentId)]);
+    return NextResponse.json({ agent, checks });
   } catch (e) {
     if (e instanceof ApiError && e.status === 404) {
       return NextResponse.json(

web/src/app/api/poll/events/route.ts

@@ -1,20 +1,21 @@
 import { NextResponse } from "next/server";
 
-import { loadEventsWithLiveness } from "@/lib/loaders";
+import { loadEvents } from "@/lib/loaders";
+import { normalizePageSize } from "@/lib/pagination";
 import { jsonError } from "@/lib/poll-response";
 
 export const dynamic = "force-dynamic";
 
 export async function GET(request: Request) {
   const url = new URL(request.url);
-  const limit = Number(url.searchParams.get("limit") ?? "100");
+  const limit = normalizePageSize(url.searchParams.get("limit"), 50);
 
   try {
-    const data = await loadEventsWithLiveness({
+    const data = await loadEvents({
       agentId: url.searchParams.get("agent_id") ?? undefined,
       checkId: url.searchParams.get("check_id") ?? undefined,
       cursor: url.searchParams.get("cursor") ?? undefined,
-      limit: Number.isFinite(limit) ? limit : 100,
+      limit,
     });
     return NextResponse.json(data);
   } catch (e) {

web/src/app/api/poll/incidents/route.ts

@@ -11,8 +11,8 @@ export async function GET(request: Request) {
   const state = stateParam === "open" || stateParam === "resolved" ? stateParam : undefined;
 
   try {
-    const data = await loadIncidents(state);
-    return NextResponse.json(data);
+    const items = await loadIncidents(state);
+    return NextResponse.json({ items });
   } catch (e) {
     return jsonError(e);
   }

web/src/app/api/poll/outbox/route.ts

@@ -1,18 +1,14 @@
 import { NextResponse } from "next/server";
 
-import { api } from "@/lib/api";
+import { loadOutboxAll } from "@/lib/loaders";
 import { jsonError } from "@/lib/poll-response";
 
 export const dynamic = "force-dynamic";
 
-export async function GET(request: Request) {
-  const url = new URL(request.url);
-
+export async function GET() {
   try {
-    const data = await api.listOutbox({
-      cursor: url.searchParams.get("cursor") ?? undefined,
-    });
-    return NextResponse.json(data);
+    const items = await loadOutboxAll();
+    return NextResponse.json({ items });
   } catch (e) {
     return jsonError(e);
   }

web/src/app/checks/[check_id]/page.tsx

@@ -1,8 +1,8 @@
 import { CheckDetailBrowser } from "@/components/CheckDetailBrowser";
 import { ErrorPanel } from "@/components/DataPanel";
 import { api } from "@/lib/api";
-import { withLivenessEvents } from "@/lib/check-groups";
 import { loadInventory } from "@/lib/loaders";
+import { normalizePageSize } from "@/lib/pagination";
 
 export const dynamic = "force-dynamic";
 
@@ -18,22 +18,24 @@ export default async function CheckDetailPage({
   searchParams,
 }: {
   params: Promise<{ check_id: string }>;
-  searchParams: Promise<{ tab?: string }>;
+  searchParams: Promise<{ tab?: string; events_limit?: string; cursor?: string }>;
 }) {
   const { check_id } = await params;
   const sp = await searchParams;
   const tab = normalizeTab(sp.tab);
+  const eventsLimit = normalizePageSize(sp.events_limit, 50);
+  const eventsCursor = sp.cursor;
 
   let data;
   let events: EventsPage = { items: [], next_cursor: null };
   try {
     data = await loadInventory();
     if (tab === "events") {
-      const rawEvents = await api.queryEvents({ check_id, limit: 50 });
-      events = {
-        ...rawEvents,
-        items: withLivenessEvents(data.agents, rawEvents.items, { checkId: check_id }),
-      };
+      events = await api.queryEvents({
+        check_id,
+        limit: eventsLimit,
+        cursor: eventsCursor,
+      });
     }
   } catch (e) {
     return <ErrorPanel error={e} />;
@@ -41,11 +43,13 @@ export default async function CheckDetailPage({
 
   return (
     <CheckDetailBrowser
-      key={`${check_id}:${tab}`}
+      key={`${check_id}:${tab}:${eventsLimit}:${eventsCursor ?? ""}`}
       checkId={check_id}
       initialData={data}
       initialEvents={events}
       tab={tab}
+      eventsLimit={eventsLimit}
+      eventsCursor={eventsCursor}
     />
   );
 }

web/src/app/events/page.tsx

@@ -1,32 +1,41 @@
 import { ErrorPanel } from "@/components/DataPanel";
 import { EventsBrowser } from "@/components/EventsBrowser";
-import { loadEventsWithLiveness } from "@/lib/loaders";
+import { loadEvents } from "@/lib/loaders";
+import { normalizePageSize } from "@/lib/pagination";
 
 export const dynamic = "force-dynamic";
 
 export default async function EventsPage({
   searchParams,
 }: {
-  searchParams: Promise<{ cursor?: string; agent_id?: string; check_id?: string }>;
+  searchParams: Promise<{
+    cursor?: string;
+    agent_id?: string;
+    check_id?: string;
+    limit?: string;
+  }>;
 }) {
   const sp = await searchParams;
+  const limit = normalizePageSize(sp.limit);
   let data;
   try {
-    data = await loadEventsWithLiveness({
+    data = await loadEvents({
       agentId: sp.agent_id,
       checkId: sp.check_id,
       cursor: sp.cursor,
+      limit,
     });
   } catch (e) {
     return <ErrorPanel error={e} />;
   }
   return (
     <EventsBrowser
-      key={`${sp.cursor ?? ""}:${sp.agent_id ?? ""}:${sp.check_id ?? ""}`}
+      key={`${sp.cursor ?? ""}:${sp.agent_id ?? ""}:${sp.check_id ?? ""}:${limit}`}
       initialData={data}
       cursor={sp.cursor}
       agentId={sp.agent_id}
       checkId={sp.check_id}
+      limit={limit}
     />
   );
 }

web/src/app/incidents/page.tsx

@@ -11,17 +11,17 @@ export default async function IncidentsPage({
 }) {
   const sp = await searchParams;
   const state = sp.state === "open" || sp.state === "resolved" ? sp.state : undefined;
-  let data;
+  let items;
   let inventory;
   try {
-    [data, inventory] = await Promise.all([loadIncidents(state), loadInventory()]);
+    [items, inventory] = await Promise.all([loadIncidents(state), loadInventory()]);
   } catch (e) {
     return <ErrorPanel error={e} />;
   }
   return (
     <IncidentsBrowser
       key={state ?? ""}
-      initialData={data}
+      initialItems={items}
       initialInventory={inventory}
       state={state}
     />

web/src/app/outbox/page.tsx

@@ -1,20 +1,15 @@
 import { ErrorPanel } from "@/components/DataPanel";
 import { OutboxBrowser } from "@/components/OutboxBrowser";
-import { api } from "@/lib/api";
+import { loadOutboxAll } from "@/lib/loaders";
 
 export const dynamic = "force-dynamic";
 
-export default async function OutboxPage({
-  searchParams,
-}: {
-  searchParams: Promise<{ cursor?: string }>;
-}) {
-  const sp = await searchParams;
-  let data;
+export default async function OutboxPage() {
+  let items;
   try {
-    data = await api.listOutbox({ cursor: sp.cursor });
+    items = await loadOutboxAll();
   } catch (e) {
     return <ErrorPanel error={e} />;
   }
-  return <OutboxBrowser key={sp.cursor ?? ""} initialData={data} cursor={sp.cursor} />;
+  return <OutboxBrowser initialItems={items} />;
 }

web/src/components/AgentDetailBrowser.tsx

@@ -1,28 +1,37 @@
 "use client";
 
 import Link from "next/link";
-import { useMemo } from "react";
+import { useRouter } from "next/navigation";
+import { useMemo, useState } from "react";
 
 import { AgentFeatures } from "@/components/AgentFeatures";
 import { CheckEventsLink } from "@/components/CheckEventsLink";
-import { Td, Th } from "@/components/DataPanel";
+import { ClientPager } from "@/components/ClientPager";
+import { EmptyPanel, SummaryCell, Td, Th } from "@/components/DataPanel";
+import { DetailTabs } from "@/components/DetailTabs";
 import { LabelChips } from "@/components/Labels";
+import { PageSizeSelect } from "@/components/PageSizeSelect";
+import { Pager } from "@/components/Pager";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
-import { withLivenessChecks } from "@/lib/check-groups";
 import { statusBadgeClass } from "@/lib/format";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 
 type Agent = components["schemas"]["Agent"];
 type CheckState = components["schemas"]["CheckState"];
 type StoredEvent = components["schemas"]["StoredCheckResultEvent"];
+type EventsPageData = { items: StoredEvent[]; next_cursor?: string | null };
 type SortKey = "severity" | "check_id" | "last_seen";
 type TabKey = "checks" | "events";
-type AgentDetailData = {
-  agent: Agent;
-  checks: CheckState[];
-  events: StoredEvent[];
-};
+type AgentDetailData = { agent: Agent; checks: CheckState[] };
+type AgentPollPayload = AgentDetailData & { events?: StoredEvent[] };
 
 const severityRank: Record<CheckState["status"], number> = {
   critical: 0,
@@ -33,22 +42,24 @@ const severityRank: Record<CheckState["status"], number> = {
 
 export function AgentDetailBrowser({
   initialData,
+  initialEvents,
   sort,
   tab,
+  eventsLimit,
+  eventsCursor,
 }: {
   initialData: AgentDetailData;
+  initialEvents: EventsPageData;
   sort: SortKey;
   tab: TabKey;
+  eventsLimit: PageSize;
+  eventsCursor?: string;
 }) {
-  const { data } = usePolling(
-    initialData,
-    `/api/poll/agent?agent_id=${encodeURIComponent(initialData.agent.agent_id)}`,
-  );
-  const { agent, events } = data;
-  const checks = useMemo(
-    () => sortChecks(withLivenessChecks([agent], data.checks), sort),
-    [agent, data.checks, sort],
-  );
+  const agentId = initialData.agent.agent_id;
+  const pollUrl = `/api/poll/agent?agent_id=${encodeURIComponent(agentId)}`;
+  const { data } = usePolling<AgentPollPayload>(initialData, pollUrl);
+  const agent = data.agent;
+  const checks = useMemo(() => sortChecks(data.checks, sort), [data.checks, sort]);
 
   return (
     <div className="space-y-6">
@@ -76,28 +87,32 @@ export function AgentDetailBrowser({
           <LabelChips labels={agent.labels} />
         </dd>
       </dl>
-      <TabNav agentId={agent.agent_id} current={tab} sort={sort} />
-      {tab === "checks" ? <ChecksTable agentId={agent.agent_id} checks={checks} sort={sort} /> : <EventsTable events={events} />}
-    </div>
-  );
-}
-
-function TabNav({ agentId, current, sort }: { agentId: string; current: TabKey; sort: SortKey }) {
-  const base = `/agents/${encodeURIComponent(agentId)}`;
-  return (
-    <div className="flex gap-4 border-b border-neutral-800 text-sm">
-      <Link
-        href={`${base}?tab=checks&sort=${sort}`}
-        className={`pb-2 ${current === "checks" ? "border-b border-neutral-200 text-neutral-100" : "text-neutral-400 hover:text-neutral-200"}`}
-      >
-        Checks
-      </Link>
-      <Link
-        href={`${base}?tab=events&sort=${sort}`}
-        className={`pb-2 ${current === "events" ? "border-b border-neutral-200 text-neutral-100" : "text-neutral-400 hover:text-neutral-200"}`}
-      >
-        Events
-      </Link>
+      <DetailTabs
+        current={tab}
+        tabs={[
+          {
+            key: "checks",
+            label: "Checks",
+            href: `/agents/${encodeURIComponent(agentId)}?tab=checks&sort=${sort}`,
+          },
+          {
+            key: "events",
+            label: "Events",
+            href: `/agents/${encodeURIComponent(agentId)}?tab=events&sort=${sort}&events_limit=${eventsLimit}`,
+          },
+        ]}
+      />
+      {tab === "checks" ? (
+        <ChecksTable agentId={agentId} checks={checks} sort={sort} />
+      ) : (
+        <EventsTable
+          agentId={agentId}
+          sort={sort}
+          eventsLimit={eventsLimit}
+          eventsCursor={eventsCursor}
+          initialEvents={initialEvents}
+        />
+      )}
     </div>
   );
 }
@@ -111,9 +126,22 @@ function ChecksTable({
   checks: CheckState[];
   sort: SortKey;
 }) {
-  if (checks.length === 0) return <div className="text-sm text-neutral-500">No checks.</div>;
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
+  const pageCount = pageCountOf(checks.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(checks, currentPage, pageSize);
+
+  if (checks.length === 0) return <EmptyPanel label="No checks" />;
   return (
     <section>
+      <div className="mb-3 flex justify-end">
+        <PageSizeSelect value={pageSize} onChange={onPageSizeChange} />
+      </div>
       <table className="w-full text-sm">
         <thead>
           <tr>
@@ -136,7 +164,7 @@ function ChecksTable({
           </tr>
         </thead>
         <tbody>
-          {checks.map((c) => (
+          {visible.map((c) => (
             <tr key={c.check_id}>
               <Td>
                 <CheckEventsLink agentId={agentId} checkId={c.check_id} />
@@ -145,19 +173,50 @@ function ChecksTable({
               <Td>
                 <DateTime iso={c.last_observed_at} />
               </Td>
-              <Td className="max-w-md truncate text-xs text-neutral-400">{c.summary ?? "—"}</Td>
+              <SummaryCell text={c.summary} />
             </tr>
           ))}
         </tbody>
       </table>
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
     </section>
   );
 }
 
-function EventsTable({ events }: { events: StoredEvent[] }) {
-  if (events.length === 0) return <div className="text-sm text-neutral-500">No events.</div>;
+function EventsTable({
+  agentId,
+  sort,
+  eventsLimit,
+  eventsCursor,
+  initialEvents,
+}: {
+  agentId: string;
+  sort: SortKey;
+  eventsLimit: PageSize;
+  eventsCursor?: string;
+  initialEvents: EventsPageData;
+}) {
+  const router = useRouter();
+  const pollUrl = useMemo(() => {
+    const qs = new URLSearchParams({ agent_id: agentId, limit: String(eventsLimit) });
+    if (eventsCursor) qs.set("cursor", eventsCursor);
+    return `/api/poll/events?${qs.toString()}`;
+  }, [agentId, eventsCursor, eventsLimit]);
+  const { data } = usePolling(initialEvents, pollUrl);
+
+  const onLimitChange = (next: PageSize) => {
+    const qs = new URLSearchParams({ tab: "events", sort, events_limit: String(next) });
+    router.push(`/agents/${encodeURIComponent(agentId)}?${qs.toString()}`);
+  };
+
   return (
     <section>
+      <div className="mb-3 flex justify-end">
+        <PageSizeSelect value={eventsLimit} onChange={onLimitChange} />
+      </div>
+      {data.items.length === 0 ? (
+        <EmptyPanel label="No events" />
+      ) : (
         <table className="w-full text-sm">
           <thead>
             <tr>
@@ -168,7 +227,7 @@ function EventsTable({ events }: { events: StoredEvent[] }) {
             </tr>
           </thead>
           <tbody>
-          {events.map((e) => (
+            {data.items.map((e) => (
               <tr key={e.event_id}>
                 <Td>
                   <DateTime iso={e.observed_at} />
@@ -182,6 +241,13 @@ function EventsTable({ events }: { events: StoredEvent[] }) {
             ))}
           </tbody>
         </table>
+      )}
+      <Pager
+        basePath={`/agents/${encodeURIComponent(agentId)}`}
+        cursor={eventsCursor}
+        nextCursor={data.next_cursor}
+        extra={{ tab: "events", sort, events_limit: String(eventsLimit) }}
+      />
     </section>
   );
 }

web/src/components/AgentLink.tsx

@@ -0,0 +1,19 @@
+import Link from "next/link";
+
+import type { components } from "@/lib/api-types";
+
+type Agent = components["schemas"]["Agent"];
+
+export function AgentLink({ agent, agentId }: { agent?: Agent; agentId: string }) {
+  const hostname = agent?.hostname || agentId;
+  const showId = agent && agent.hostname && agent.hostname !== agentId;
+  return (
+    <Link
+      href={`/agents/${encodeURIComponent(agentId)}`}
+      className="inline-flex flex-col text-blue-300 hover:text-blue-200"
+    >
+      <span>{hostname}</span>
+      {showId ? <span className="text-xs text-neutral-500">{agentId}</span> : null}
+    </Link>
+  );
+}

web/src/components/AgentsBrowser.tsx

@@ -1,13 +1,24 @@
 "use client";
 
-import Link from "next/link";
 import { useMemo, useState } from "react";
 
 import { AgentFeatures } from "@/components/AgentFeatures";
+import { AgentLink } from "@/components/AgentLink";
+import { ClientPager } from "@/components/ClientPager";
+import { EmptyPanel, Td, Th } from "@/components/DataPanel";
 import { LabelChips } from "@/components/Labels";
+import { ListToolbar } from "@/components/ListToolbar";
+import { SortHeaderButton, type SortDir } from "@/components/SortHeaderButton";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
 import { statusBadgeClass } from "@/lib/format";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 import type { InventoryData } from "@/lib/view-types";
 
@@ -16,7 +27,6 @@ type CheckState = components["schemas"]["CheckState"];
 type CheckStatus = CheckState["status"];
 type CheckCounts = Record<CheckStatus, number>;
 type SortField = "host" | "status" | "last_seen_at";
-type SortDir = "asc" | "desc";
 
 export type AgentRow = { agent: Agent; checks: CheckCounts };
 
@@ -36,77 +46,75 @@ export function AgentsBrowser({ initialData }: { initialData: InventoryData }) {
     [dir, initialRows, query, sort],
   );
 
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const pageCount = pageCountOf(rows.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(rows, currentPage, pageSize);
+
+  const onQueryChange = (value: string) => {
+    setQuery(value);
+    setPage(1);
+  };
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
   const chooseSort = (field: SortField) => {
     if (field === sort) {
       setDir((current) => (current === "asc" ? "desc" : "asc"));
-      return;
-    }
+    } else {
       setSort(field);
       setDir(fieldDefaultDir(field));
+    }
+    setPage(1);
   };
 
   return (
     <>
       <div className="mb-4 flex items-baseline gap-3">
         <h1 className="text-lg font-semibold">Agents</h1>
-        <span className="text-sm text-neutral-400">{rows.length} items</span>
+        <span className="text-sm text-neutral-400">
+          {rows.length} of {initialRows.length} items
+        </span>
       </div>
-      <div className="mb-4 flex max-w-md gap-2">
-        <input
-          type="search"
-          value={query}
-          onChange={(event) => setQuery(event.target.value)}
+      <ListToolbar
+        query={query}
+        onQueryChange={onQueryChange}
         placeholder="search agent"
-          className="min-w-0 flex-1 border border-neutral-800 bg-neutral-950 px-2 py-1.5 text-sm text-neutral-100 outline-none focus:border-neutral-500"
+        pageSize={pageSize}
+        onPageSizeChange={onPageSizeChange}
       />
-        {query ? (
-          <button
-            type="button"
-            onClick={() => setQuery("")}
-            className="border border-neutral-900 px-3 py-1.5 text-sm text-neutral-500 hover:text-neutral-300"
-          >
-            clear
-          </button>
-        ) : null}
-      </div>
       {rows.length === 0 ? (
-        <div className="text-sm text-neutral-500 italic">No data.</div>
+        <EmptyPanel />
       ) : (
         <table className="w-full text-sm">
           <thead>
             <tr>
               <Th>
-                <SortButton field="host" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="host" current={sort} dir={dir} onClick={chooseSort}>
                   HOST
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="status" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="status" current={sort} dir={dir} onClick={chooseSort}>
                   STATUS
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="last_seen_at" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="last_seen_at" current={sort} dir={dir} onClick={chooseSort}>
                   LAST_SEEN_AT
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>features</Th>
               <Th>labels</Th>
             </tr>
           </thead>
           <tbody>
-            {rows.map(({ agent: a, checks }) => (
+            {visible.map(({ agent: a, checks }) => (
               <tr key={a.agent_id}>
                 <Td>
-                  <Link
-                    href={`/agents/${encodeURIComponent(a.agent_id)}`}
-                    className="inline-flex flex-col text-blue-300 hover:text-blue-200"
-                  >
-                    <span>{a.hostname}</span>
-                    {a.agent_id !== a.hostname ? (
-                      <span className="text-xs text-neutral-500">{a.agent_id}</span>
-                    ) : null}
-                  </Link>
+                  <AgentLink agent={a} agentId={a.agent_id} />
                 </Td>
                 <Td>
                   <AgentStatus status={a.status} checks={checks} />
@@ -125,50 +133,11 @@ export function AgentsBrowser({ initialData }: { initialData: InventoryData }) {
           </tbody>
         </table>
       )}
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
     </>
   );
 }
 
-function Th({ children }: { children: React.ReactNode }) {
-  return (
-    <th className="text-left text-xs font-semibold uppercase tracking-wide text-neutral-400 border-b border-neutral-800 px-2 py-2">
-      {children}
-    </th>
-  );
-}
-
-function Td({ children, className = "" }: { children: React.ReactNode; className?: string }) {
-  return (
-    <td className={`px-2 py-1.5 border-b border-neutral-900 align-top ${className}`}>{children}</td>
-  );
-}
-
-function SortButton({
-  field,
-  current,
-  dir,
-  onClick,
-  children,
-}: {
-  field: SortField;
-  current: SortField;
-  dir: SortDir;
-  onClick: (field: SortField) => void;
-  children: React.ReactNode;
-}) {
-  const active = field === current;
-  return (
-    <button
-      type="button"
-      onClick={() => onClick(field)}
-      className={`inline-flex items-center gap-1 hover:text-neutral-100 ${active ? "text-neutral-100" : ""}`}
-    >
-      <span>{children}</span>
-      {active ? <span className="text-neutral-500">{dir === "asc" ? "↑" : "↓"}</span> : null}
-    </button>
-  );
-}
-
 function filterAgents(rows: AgentRow[], query: string): AgentRow[] {
   const needle = query.trim().toLowerCase();
   if (!needle) return rows;

web/src/components/CheckDetailBrowser.tsx

@@ -1,20 +1,27 @@
 "use client";
 
 import Link from "next/link";
-import { useMemo } from "react";
+import { useRouter } from "next/navigation";
+import { useMemo, useState } from "react";
 
+import { AgentLink } from "@/components/AgentLink";
 import { CheckStatusSummary } from "@/components/CheckStatusSummary";
-import { Td, Th } from "@/components/DataPanel";
+import { ClientPager } from "@/components/ClientPager";
+import { EmptyPanel, SummaryCell, Td, Th } from "@/components/DataPanel";
+import { DetailTabs } from "@/components/DetailTabs";
+import { PageSizeSelect } from "@/components/PageSizeSelect";
+import { Pager } from "@/components/Pager";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
-import {
-  groupChecks,
-  statusSeverity,
-  withLivenessChecks,
-  type Agent,
-  type CheckGroup,
-} from "@/lib/check-groups";
+import { groupChecks, statusSeverity, type Agent, type CheckGroup } from "@/lib/check-groups";
 import { statusBadgeClass } from "@/lib/format";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 import type { InventoryData } from "@/lib/view-types";
 
@@ -27,21 +34,24 @@ export function CheckDetailBrowser({
   initialData,
   initialEvents,
   tab,
+  eventsLimit,
+  eventsCursor,
 }: {
   checkId: string;
   initialData: InventoryData;
   initialEvents: EventsPageData;
   tab: TabKey;
+  eventsLimit: PageSize;
+  eventsCursor?: string;
 }) {
   const { data } = usePolling(initialData, "/api/poll/inventory");
-  const agentsById = useMemo(() => new Map(data.agents.map((agent) => [agent.agent_id, agent])), [data.agents]);
-  const checks = useMemo(
-    () => withLivenessChecks(data.agents, data.checks),
-    [data.agents, data.checks],
+  const agentsById = useMemo(
+    () => new Map(data.agents.map((agent) => [agent.agent_id, agent])),
+    [data.agents],
   );
   const group = useMemo(
-    () => groupChecks(checks, agentsById).find((item) => item.checkId === checkId),
-    [agentsById, checkId, checks],
+    () => groupChecks(data.checks, agentsById).find((item) => item.checkId === checkId),
+    [agentsById, checkId, data.checks],
   );
 
   if (!group) {
@@ -76,44 +86,62 @@ export function CheckDetailBrowser({
           <DateTime iso={group.lastObservedAt} />
         </dd>
       </dl>
-      <TabNav checkId={checkId} current={tab} />
+      <DetailTabs
+        current={tab}
+        tabs={[
+          {
+            key: "agents",
+            label: "Agents",
+            href: `/checks/${encodeURIComponent(checkId)}?tab=agents`,
+          },
+          {
+            key: "events",
+            label: "Events",
+            href: `/checks/${encodeURIComponent(checkId)}?tab=events&events_limit=${eventsLimit}`,
+          },
+        ]}
+      />
       {tab === "agents" ? (
         <AgentsForCheck group={group} />
       ) : (
-        <EventsForCheck checkId={checkId} initialData={initialEvents} agentsById={agentsById} />
+        <EventsForCheck
+          checkId={checkId}
+          initialData={initialEvents}
+          agentsById={agentsById}
+          eventsLimit={eventsLimit}
+          eventsCursor={eventsCursor}
+        />
       )}
     </div>
   );
 }
 
-function TabNav({ checkId, current }: { checkId: string; current: TabKey }) {
-  const base = `/checks/${encodeURIComponent(checkId)}`;
-  return (
-    <div className="flex gap-4 border-b border-neutral-800 text-sm">
-      <Link
-        href={`${base}?tab=agents`}
-        className={`pb-2 ${current === "agents" ? "border-b border-neutral-200 text-neutral-100" : "text-neutral-400 hover:text-neutral-200"}`}
-      >
-        Agents
-      </Link>
-      <Link
-        href={`${base}?tab=events`}
-        className={`pb-2 ${current === "events" ? "border-b border-neutral-200 text-neutral-100" : "text-neutral-400 hover:text-neutral-200"}`}
-      >
-        Events
-      </Link>
-    </div>
-  );
-}
-
 function AgentsForCheck({ group }: { group: CheckGroup }) {
-  const rows = [...group.checks].sort(
+  const rows = useMemo(
+    () =>
+      [...group.checks].sort(
         (a, b) =>
           statusSeverity[b.check.status] - statusSeverity[a.check.status] ||
           hostName(a).localeCompare(hostName(b)),
+      ),
+    [group.checks],
   );
 
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
+  const pageCount = pageCountOf(rows.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(rows, currentPage, pageSize);
+
   return (
+    <section>
+      <div className="mb-3 flex justify-end">
+        <PageSizeSelect value={pageSize} onChange={onPageSizeChange} />
+      </div>
       <table className="w-full text-sm">
         <thead>
           <tr>
@@ -124,28 +152,22 @@ function AgentsForCheck({ group }: { group: CheckGroup }) {
           </tr>
         </thead>
         <tbody>
-        {rows.map(({ check, agent }) => (
+          {visible.map(({ check, agent }) => (
             <tr key={check.agent_id}>
               <Td>
-              <Link
-                href={`/agents/${encodeURIComponent(check.agent_id)}`}
-                className="inline-flex flex-col text-blue-300 hover:text-blue-200"
-              >
-                <span>{agent?.hostname || check.agent_id}</span>
-                {agent && agent.hostname !== check.agent_id ? (
-                  <span className="text-xs text-neutral-500">{check.agent_id}</span>
-                ) : null}
-              </Link>
+                <AgentLink agent={agent} agentId={check.agent_id} />
               </Td>
               <Td className={statusBadgeClass(check.status)}>{check.status}</Td>
               <Td>
                 <DateTime iso={check.last_observed_at} />
               </Td>
-            <Td className="max-w-md truncate text-xs text-neutral-400">{check.summary ?? "—"}</Td>
+              <SummaryCell text={check.summary} />
             </tr>
           ))}
         </tbody>
       </table>
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
+    </section>
   );
 }
 
@@ -153,19 +175,40 @@ function EventsForCheck({
   checkId,
   initialData,
   agentsById,
+  eventsLimit,
+  eventsCursor,
 }: {
   checkId: string;
   initialData: EventsPageData;
   agentsById: Map<string, Agent>;
+  eventsLimit: PageSize;
+  eventsCursor?: string;
 }) {
-  const { data } = usePolling(
-    initialData,
-    `/api/poll/events?check_id=${encodeURIComponent(checkId)}&limit=50`,
-  );
+  const router = useRouter();
+  const pollUrl = useMemo(() => {
+    const qs = new URLSearchParams({
+      check_id: checkId,
+      limit: String(eventsLimit),
+    });
+    if (eventsCursor) qs.set("cursor", eventsCursor);
+    return `/api/poll/events?${qs.toString()}`;
+  }, [checkId, eventsCursor, eventsLimit]);
+  const { data } = usePolling(initialData, pollUrl);
 
-  if (data.items.length === 0) return <div className="text-sm text-neutral-500">No events.</div>;
+  const onLimitChange = (next: PageSize) => {
+    router.push(
+      `/checks/${encodeURIComponent(checkId)}?tab=events&events_limit=${next}`,
+    );
+  };
 
   return (
+    <section>
+      <div className="mb-3 flex justify-end">
+        <PageSizeSelect value={eventsLimit} onChange={onLimitChange} />
+      </div>
+      {data.items.length === 0 ? (
+        <EmptyPanel label="No events" />
+      ) : (
         <table className="w-full text-sm">
           <thead>
             <tr>
@@ -189,21 +232,24 @@ function EventsForCheck({
                     <DateTime iso={event.received_at} />
                   </Td>
                   <Td>
-                <Link
-                  href={`/agents/${encodeURIComponent(event.agent_id)}`}
-                  className="text-blue-300 hover:text-blue-200"
-                >
-                  {agent?.hostname || event.agent_id}
-                </Link>
+                    <AgentLink agent={agent} agentId={event.agent_id} />
                   </Td>
                   <Td className={statusBadgeClass(event.status)}>{event.status}</Td>
                   <Td>{event.duration_ms}</Td>
-              <Td className="max-w-md truncate text-xs text-neutral-400">{event.output ?? "—"}</Td>
+                  <SummaryCell text={event.output} />
                 </tr>
               );
             })}
           </tbody>
         </table>
+      )}
+      <Pager
+        basePath={`/checks/${encodeURIComponent(checkId)}`}
+        cursor={eventsCursor}
+        nextCursor={data.next_cursor}
+        extra={{ tab: "events", events_limit: String(eventsLimit) }}
+      />
+    </section>
   );
 }
 

web/src/components/ChecksBrowser.tsx

@@ -4,17 +4,27 @@ import Link from "next/link";
 import { useMemo, useState } from "react";
 
 import { CheckStatusSummary } from "@/components/CheckStatusSummary";
+import { ClientPager } from "@/components/ClientPager";
+import { EmptyPanel, Td, Th } from "@/components/DataPanel";
+import { ListToolbar } from "@/components/ListToolbar";
+import { SortHeaderButton, type SortDir } from "@/components/SortHeaderButton";
 import { DateTime } from "@/components/TimeZoneControls";
 import {
   compareStatusCounts,
   groupChecks,
   type CheckGroup,
 } from "@/lib/check-groups";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 import type { InventoryData } from "@/lib/view-types";
 
 type SortField = "check" | "status" | "last_observed_at";
-type SortDir = "asc" | "desc";
 
 export function ChecksBrowser({ initialData }: { initialData: InventoryData }) {
   const { data } = usePolling(initialData, "/api/poll/inventory");
@@ -29,65 +39,71 @@ export function ChecksBrowser({ initialData }: { initialData: InventoryData }) {
     [dir, groups, query, sort],
   );
 
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const pageCount = pageCountOf(rows.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(rows, currentPage, pageSize);
+
+  const onQueryChange = (value: string) => {
+    setQuery(value);
+    setPage(1);
+  };
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
   const chooseSort = (field: SortField) => {
     if (field === sort) {
       setDir((current) => (current === "asc" ? "desc" : "asc"));
-      return;
-    }
+    } else {
       setSort(field);
       setDir(fieldDefaultDir(field));
+    }
+    setPage(1);
   };
 
   return (
     <>
       <div className="mb-4 flex items-baseline gap-3">
         <h1 className="text-lg font-semibold">Checks</h1>
-        <span className="text-sm text-neutral-400">{rows.length} items</span>
+        <span className="text-sm text-neutral-400">
+          {rows.length} of {groups.length} items
+        </span>
       </div>
-      <div className="mb-4 flex max-w-md gap-2">
-        <input
-          type="search"
-          value={query}
-          onChange={(event) => setQuery(event.target.value)}
+      <ListToolbar
+        query={query}
+        onQueryChange={onQueryChange}
         placeholder="search check"
-          className="min-w-0 flex-1 border border-neutral-800 bg-neutral-950 px-2 py-1.5 text-sm text-neutral-100 outline-none focus:border-neutral-500"
+        pageSize={pageSize}
+        onPageSizeChange={onPageSizeChange}
       />
-        {query ? (
-          <button
-            type="button"
-            onClick={() => setQuery("")}
-            className="border border-neutral-900 px-3 py-1.5 text-sm text-neutral-500 hover:text-neutral-300"
-          >
-            clear
-          </button>
-        ) : null}
-      </div>
       {rows.length === 0 ? (
-        <div className="text-sm text-neutral-500 italic">No data.</div>
+        <EmptyPanel />
       ) : (
         <table className="w-full text-sm">
           <thead>
             <tr>
               <Th>
-                <SortButton field="check" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="check" current={sort} dir={dir} onClick={chooseSort}>
                   CHECK
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="status" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="status" current={sort} dir={dir} onClick={chooseSort}>
                   STATUS
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="last_observed_at" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="last_observed_at" current={sort} dir={dir} onClick={chooseSort}>
                   LAST_OBSERVED_AT
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>AGENTS</Th>
             </tr>
           </thead>
           <tbody>
-            {rows.map((row) => (
+            {visible.map((row) => (
               <tr key={row.checkId}>
                 <Td>
                   <Link
@@ -109,48 +125,11 @@ export function ChecksBrowser({ initialData }: { initialData: InventoryData }) {
           </tbody>
         </table>
       )}
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
     </>
   );
 }
 
-function Th({ children }: { children: React.ReactNode }) {
-  return (
-    <th className="border-b border-neutral-800 px-2 py-2 text-left text-xs font-semibold uppercase tracking-wide text-neutral-400">
-      {children}
-    </th>
-  );
-}
-
-function Td({ children, className = "" }: { children: React.ReactNode; className?: string }) {
-  return <td className={`border-b border-neutral-900 px-2 py-1.5 align-top ${className}`}>{children}</td>;
-}
-
-function SortButton({
-  field,
-  current,
-  dir,
-  onClick,
-  children,
-}: {
-  field: SortField;
-  current: SortField;
-  dir: SortDir;
-  onClick: (field: SortField) => void;
-  children: React.ReactNode;
-}) {
-  const active = field === current;
-  return (
-    <button
-      type="button"
-      onClick={() => onClick(field)}
-      className={`inline-flex items-center gap-1 hover:text-neutral-100 ${active ? "text-neutral-100" : ""}`}
-    >
-      <span>{children}</span>
-      {active ? <span className="text-neutral-500">{dir === "asc" ? "↑" : "↓"}</span> : null}
-    </button>
-  );
-}
-
 function filterChecks(rows: CheckGroup[], query: string): CheckGroup[] {
   const needle = query.trim().toLowerCase();
   if (!needle) return rows;

web/src/components/ClientPager.tsx

@@ -0,0 +1,39 @@
+"use client";
+
+export function ClientPager({
+  page,
+  pageCount,
+  onPageChange,
+}: {
+  page: number;
+  pageCount: number;
+  onPageChange: (page: number) => void;
+}) {
+  const prev = () => onPageChange(Math.max(1, page - 1));
+  const next = () => onPageChange(Math.min(pageCount, page + 1));
+  const disabledPrev = page <= 1;
+  const disabledNext = page >= pageCount;
+  return (
+    <div className="mt-4 flex items-center justify-between text-sm">
+      <button
+        type="button"
+        onClick={prev}
+        disabled={disabledPrev}
+        className="text-blue-300 hover:text-blue-200 disabled:cursor-default disabled:text-neutral-600"
+      >
+        ← prev
+      </button>
+      <span className="text-neutral-500">
+        page {page} of {pageCount}
+      </span>
+      <button
+        type="button"
+        onClick={next}
+        disabled={disabledNext}
+        className="text-blue-300 hover:text-blue-200 disabled:cursor-default disabled:text-neutral-600"
+      >
+        next →
+      </button>
+    </div>
+  );
+}

web/src/components/DataPanel.tsx

@@ -39,3 +39,7 @@ export function Td({ children, className = "" }: { children: React.ReactNode; cl
     <td className={`px-2 py-1.5 border-b border-neutral-900 align-top ${className}`}>{children}</td>
   );
 }
+
+export function SummaryCell({ text }: { text?: string | null }) {
+  return <Td className="max-w-md truncate text-xs text-neutral-400">{text ?? "—"}</Td>;
+}

web/src/components/DetailTabs.tsx

@@ -0,0 +1,23 @@
+import Link from "next/link";
+
+export type DetailTab = { key: string; label: string; href: string };
+
+export function DetailTabs({ tabs, current }: { tabs: DetailTab[]; current: string }) {
+  return (
+    <div className="flex gap-4 border-b border-neutral-800 text-sm">
+      {tabs.map((tab) => (
+        <Link
+          key={tab.key}
+          href={tab.href}
+          className={`pb-2 ${
+            current === tab.key
+              ? "border-b border-neutral-200 text-neutral-100"
+              : "text-neutral-400 hover:text-neutral-200"
+          }`}
+        >
+          {tab.label}
+        </Link>
+      ))}
+    </div>
+  );
+}

web/src/components/EventsBrowser.tsx

@@ -1,14 +1,17 @@
 "use client";
 
 import Link from "next/link";
+import { useRouter } from "next/navigation";
 import { useMemo } from "react";
 
 import { CheckEventsLink } from "@/components/CheckEventsLink";
-import { EmptyPanel, PageHeader, Td, Th } from "@/components/DataPanel";
+import { EmptyPanel, PageHeader, SummaryCell, Td, Th } from "@/components/DataPanel";
+import { PageSizeSelect } from "@/components/PageSizeSelect";
 import { Pager } from "@/components/Pager";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
 import { statusBadgeClass } from "@/lib/format";
+import { type PageSize } from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 
 type StoredEvent = components["schemas"]["StoredCheckResultEvent"];
@@ -19,19 +22,32 @@ export function EventsBrowser({
   cursor,
   agentId,
   checkId,
+  limit,
 }: {
   initialData: EventsPageData;
   cursor?: string;
   agentId?: string;
   checkId?: string;
+  limit: PageSize;
 }) {
-  const url = useMemo(() => eventsPollUrl({ cursor, agentId, checkId }), [agentId, checkId, cursor]);
+  const router = useRouter();
+  const url = useMemo(
+    () => eventsPollUrl({ cursor, agentId, checkId, limit }),
+    [agentId, checkId, cursor, limit],
+  );
   const { data } = usePolling(initialData, url);
 
+  const onLimitChange = (next: PageSize) => {
+    router.push(eventsHref({ agent_id: agentId, check_id: checkId, limit: next }));
+  };
+
   return (
     <>
       <PageHeader title="Events" count={data.items.length} />
-      <ActiveFilters agentId={agentId} checkId={checkId} />
+      <div className="mb-4 flex items-center justify-between gap-3">
+        <ActiveFilters agentId={agentId} checkId={checkId} limit={limit} />
+        <PageSizeSelect value={limit} onChange={onLimitChange} />
+      </div>
       {data.items.length === 0 ? (
         <EmptyPanel />
       ) : (
@@ -62,7 +78,7 @@ export function EventsBrowser({
                 </Td>
                 <Td className={statusBadgeClass(e.status)}>{e.status}</Td>
                 <Td>{e.duration_ms}</Td>
-                <Td className="max-w-md truncate text-xs text-neutral-400">{e.output ?? "—"}</Td>
+                <SummaryCell text={e.output} />
               </tr>
             ))}
           </tbody>
@@ -72,24 +88,43 @@ export function EventsBrowser({
         basePath="/events"
         cursor={cursor}
         nextCursor={data.next_cursor}
-        extra={{ agent_id: agentId, check_id: checkId }}
+        extra={{ agent_id: agentId, check_id: checkId, limit: String(limit) }}
       />
     </>
   );
 }
 
-function ActiveFilters({ agentId, checkId }: { agentId?: string; checkId?: string }) {
-  if (!agentId && !checkId) return null;
+function ActiveFilters({
+  agentId,
+  checkId,
+  limit,
+}: {
+  agentId?: string;
+  checkId?: string;
+  limit: PageSize;
+}) {
+  if (!agentId && !checkId) return <div />;
 
   return (
-    <div className="mb-4 flex flex-wrap items-center gap-2 text-xs">
+    <div className="flex flex-wrap items-center gap-2 text-xs">
       {agentId ? (
-        <FilterChip label="agent_id" value={agentId} href={eventsHref({ check_id: checkId })} />
+        <FilterChip
+          label="agent_id"
+          value={agentId}
+          href={eventsHref({ check_id: checkId, limit })}
+        />
       ) : null}
       {checkId ? (
-        <FilterChip label="check_id" value={checkId} href={eventsHref({ agent_id: agentId })} />
+        <FilterChip
+          label="check_id"
+          value={checkId}
+          href={eventsHref({ agent_id: agentId, limit })}
+        />
       ) : null}
-      <Link href="/events" className="text-neutral-500 hover:text-neutral-300">
+      <Link
+        href={eventsHref({ limit })}
+        className="text-neutral-500 hover:text-neutral-300"
+      >
         clear
       </Link>
     </div>
@@ -110,10 +145,15 @@ function FilterChip({ label, value, href }: { label: string; value: string; href
   );
 }
 
-function eventsHref(params: { agent_id?: string; check_id?: string }): string {
+function eventsHref(params: {
+  agent_id?: string;
+  check_id?: string;
+  limit?: PageSize;
+}): string {
   const qs = new URLSearchParams();
   if (params.agent_id) qs.set("agent_id", params.agent_id);
   if (params.check_id) qs.set("check_id", params.check_id);
+  if (params.limit) qs.set("limit", String(params.limit));
   const query = qs.toString();
   return query ? `/events?${query}` : "/events";
 }
@@ -122,15 +162,17 @@ function eventsPollUrl({
   cursor,
   agentId,
   checkId,
+  limit,
 }: {
   cursor?: string;
   agentId?: string;
   checkId?: string;
+  limit: PageSize;
 }) {
   const qs = new URLSearchParams();
   if (cursor) qs.set("cursor", cursor);
   if (agentId) qs.set("agent_id", agentId);
   if (checkId) qs.set("check_id", checkId);
-  const query = qs.toString();
-  return query ? `/api/poll/events?${query}` : "/api/poll/events";
+  qs.set("limit", String(limit));
+  return `/api/poll/events?${qs.toString()}`;
 }

web/src/components/IncidentsBrowser.tsx

@@ -3,11 +3,22 @@
 import Link from "next/link";
 import { useMemo, useState } from "react";
 
+import { AgentLink } from "@/components/AgentLink";
 import { CheckEventsLink } from "@/components/CheckEventsLink";
-import { EmptyPanel, PageHeader, Td, Th } from "@/components/DataPanel";
+import { ClientPager } from "@/components/ClientPager";
+import { EmptyPanel, PageHeader, SummaryCell, Td, Th } from "@/components/DataPanel";
+import { PageSizeSelect } from "@/components/PageSizeSelect";
+import { SortHeaderButton, type SortDir } from "@/components/SortHeaderButton";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
 import { statusBadgeClass } from "@/lib/format";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 import type { InventoryData } from "@/lib/view-types";
 
@@ -15,49 +26,68 @@ const STATES = ["all", "open", "resolved"] as const;
 
 type Incident = components["schemas"]["Incident"];
 type Agent = components["schemas"]["Agent"];
-type IncidentsPageData = { items: Incident[] };
+type IncidentsData = { items: Incident[] };
 type SortField = "status" | "host" | "check" | "opened_at" | "resolved_at";
-type SortDir = "asc" | "desc";
 
-const stateRank: Record<Incident["state"], number> = { resolved: 0, open: 1 };
-const severityRank: Record<Incident["severity"], number> = { unknown: 1, warning: 2, critical: 3 };
+const stateRank: Record<Incident["state"], number> = { open: 0, resolved: 1 };
+const severityRank: Record<Incident["severity"], number> = {
+  critical: 0,
+  warning: 1,
+  unknown: 2,
+};
 
 export function IncidentsBrowser({
-  initialData,
+  initialItems,
   initialInventory,
   state,
 }: {
-  initialData: IncidentsPageData;
+  initialItems: Incident[];
   initialInventory: InventoryData;
   state?: "open" | "resolved";
 }) {
-  const url = useMemo(() => incidentsPollUrl({ state }), [state]);
-  const { data } = usePolling(initialData, url);
+  const url = useMemo(
+    () => (state ? `/api/poll/incidents?state=${state}` : "/api/poll/incidents"),
+    [state],
+  );
+  const { data } = usePolling<IncidentsData>({ items: initialItems }, url);
   const { data: inventory } = usePolling(initialInventory, "/api/poll/inventory");
-  const [sort, setSort] = useState<SortField>("status");
-  const [dir, setDir] = useState<SortDir>("desc");
   const agentsById = useMemo(
     () => new Map(inventory.agents.map((agent) => [agent.agent_id, agent])),
     [inventory.agents],
   );
-  const rows = useMemo(
+
+  const [sort, setSort] = useState<SortField>("status");
+  const [dir, setDir] = useState<SortDir>("asc");
+  const sorted = useMemo(
     () => sortIncidents(data.items, agentsById, sort, dir),
     [agentsById, data.items, dir, sort],
   );
 
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
   const chooseSort = (field: SortField) => {
     if (field === sort) {
       setDir((current) => (current === "asc" ? "desc" : "asc"));
-      return;
-    }
+    } else {
       setSort(field);
       setDir(fieldDefaultDir(field));
+    }
+    setPage(1);
   };
 
+  const pageCount = pageCountOf(sorted.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(sorted, currentPage, pageSize);
+
   return (
     <>
-      <PageHeader title="Incidents" count={rows.length} />
-      <div className="mb-3 flex gap-3 text-sm">
+      <PageHeader title="Incidents" count={sorted.length} />
+      <div className="mb-3 flex items-center justify-between gap-3 text-sm">
+        <div className="flex gap-3">
           {STATES.map((s) => {
             const href = s === "all" ? "/incidents" : `/incidents?state=${s}`;
             const active = (s === "all" && !state) || s === state;
@@ -72,47 +102,54 @@ export function IncidentsBrowser({
             );
           })}
         </div>
-      {rows.length === 0 ? (
+        <PageSizeSelect value={pageSize} onChange={onPageSizeChange} />
+      </div>
+      {sorted.length === 0 ? (
         <EmptyPanel />
       ) : (
         <table className="w-full text-sm">
           <thead>
             <tr>
               <Th>
-                <SortButton field="status" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="status" current={sort} dir={dir} onClick={chooseSort}>
                   STATUS
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="host" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="host" current={sort} dir={dir} onClick={chooseSort}>
                   HOST
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="check" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="check" current={sort} dir={dir} onClick={chooseSort}>
                   CHECK
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="opened_at" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="opened_at" current={sort} dir={dir} onClick={chooseSort}>
                   OPENED_AT
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>
-                <SortButton field="resolved_at" current={sort} dir={dir} onClick={chooseSort}>
+                <SortHeaderButton field="resolved_at" current={sort} dir={dir} onClick={chooseSort}>
                   RESOLVED_AT
-                </SortButton>
+                </SortHeaderButton>
               </Th>
               <Th>SUMMARY</Th>
             </tr>
           </thead>
           <tbody>
-            {rows.map(({ incident, agent }) => (
-              <IncidentRow key={incident.id} incident={incident} agent={agent} />
+            {visible.map((incident) => (
+              <IncidentRow
+                key={incident.id}
+                incident={incident}
+                agent={agentsById.get(incidentAgentId(incident))}
+              />
             ))}
           </tbody>
         </table>
       )}
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
     </>
   );
 }
@@ -128,21 +165,7 @@ function IncidentRow({ incident, agent }: { incident: Incident; agent?: Agent })
           <span className={statusBadgeClass(incident.severity)}>{incident.severity}</span>
         </div>
       </Td>
-      <Td>
-        {agentId ? (
-          <Link
-            href={`/agents/${encodeURIComponent(agentId)}`}
-            className="inline-flex flex-col text-blue-300 hover:text-blue-200"
-          >
-            <span>{agent?.hostname || agentId}</span>
-            {agent && agent.hostname !== agentId ? (
-              <span className="text-xs text-neutral-500">{agentId}</span>
-            ) : null}
-          </Link>
-        ) : (
-          "—"
-        )}
-      </Td>
+      <Td>{agentId ? <AgentLink agent={agent} agentId={agentId} /> : "—"}</Td>
       <Td>
         <IncidentCheckLink agentId={agentId} checkId={checkId} />
       </Td>
@@ -152,7 +175,7 @@ function IncidentRow({ incident, agent }: { incident: Incident; agent?: Agent })
       <Td>
         <DateTime iso={incident.resolved_at} />
       </Td>
-      <Td className="max-w-md truncate text-xs text-neutral-400">{incident.summary ?? "—"}</Td>
+      <SummaryCell text={incident.summary} />
     </tr>
   );
 }
@@ -172,97 +195,6 @@ function IncidentCheckLink({ agentId, checkId }: { agentId: string; checkId: str
   return agentId ? <CheckEventsLink agentId={agentId} checkId={checkId} /> : <span>{checkId}</span>;
 }
 
-function SortButton({
-  field,
-  current,
-  dir,
-  onClick,
-  children,
-}: {
-  field: SortField;
-  current: SortField;
-  dir: SortDir;
-  onClick: (field: SortField) => void;
-  children: React.ReactNode;
-}) {
-  const active = field === current;
-  return (
-    <button
-      type="button"
-      onClick={() => onClick(field)}
-      className={`inline-flex items-center gap-1 hover:text-neutral-100 ${active ? "text-neutral-100" : ""}`}
-    >
-      <span>{children}</span>
-      {active ? <span className="text-neutral-500">{dir === "asc" ? "↑" : "↓"}</span> : null}
-    </button>
-  );
-}
-
-function fieldDefaultDir(field: SortField): SortDir {
-  return field === "host" || field === "check" ? "asc" : "desc";
-}
-
-function sortIncidents(
-  incidents: Incident[],
-  agentsById: Map<string, Agent>,
-  sort: SortField,
-  dir: SortDir,
-): { incident: Incident; agent?: Agent }[] {
-  return incidents
-    .map((incident) => ({ incident, agent: agentsById.get(incidentAgentId(incident)) }))
-    .sort((a, b) => {
-      const primary = compareByField(a, b, sort);
-      if (primary !== 0) return dir === "asc" ? primary : -primary;
-      return fallbackCompare(a, b);
-    });
-}
-
-function compareByField(
-  a: { incident: Incident; agent?: Agent },
-  b: { incident: Incident; agent?: Agent },
-  sort: SortField,
-): number {
-  switch (sort) {
-    case "host":
-      return hostName(a).localeCompare(hostName(b)) || incidentAgentId(a.incident).localeCompare(incidentAgentId(b.incident));
-    case "check":
-      return incidentCheckId(a.incident).localeCompare(incidentCheckId(b.incident));
-    case "opened_at":
-      return Date.parse(a.incident.opened_at) - Date.parse(b.incident.opened_at);
-    case "resolved_at":
-      return dateValue(a.incident.resolved_at) - dateValue(b.incident.resolved_at);
-    case "status":
-      return compareIncidentImportance(a.incident, b.incident);
-  }
-}
-
-function compareIncidentImportance(a: Incident, b: Incident): number {
-  return (
-    stateRank[a.state] - stateRank[b.state] ||
-    severityRank[a.severity] - severityRank[b.severity] ||
-    Date.parse(a.opened_at) - Date.parse(b.opened_at)
-  );
-}
-
-function fallbackCompare(
-  a: { incident: Incident; agent?: Agent },
-  b: { incident: Incident; agent?: Agent },
-): number {
-  return (
-    compareIncidentImportance(a.incident, b.incident) ||
-    hostName(a).localeCompare(hostName(b)) ||
-    incidentCheckId(a.incident).localeCompare(incidentCheckId(b.incident))
-  );
-}
-
-function dateValue(value?: string | null): number {
-  return value ? Date.parse(value) : 0;
-}
-
-function hostName(row: { incident: Incident; agent?: Agent }): string {
-  return row.agent?.hostname || incidentAgentId(row.incident);
-}
-
 function incidentAgentId(incident: Incident): string {
   return incident.agent_id ?? "";
 }
@@ -271,6 +203,56 @@ function incidentCheckId(incident: Incident): string {
   return incident.check_id ?? "";
 }
 
-function incidentsPollUrl({ state }: { state?: string }) {
-  return state ? `/api/poll/incidents?state=${encodeURIComponent(state)}` : "/api/poll/incidents";
+function fieldDefaultDir(field: SortField): SortDir {
+  switch (field) {
+    case "status":
+      return "asc";
+    case "host":
+    case "check":
+      return "asc";
+    case "opened_at":
+    case "resolved_at":
+      return "desc";
+  }
+}
+
+function sortIncidents(
+  items: Incident[],
+  agentsById: Map<string, Agent>,
+  sort: SortField,
+  dir: SortDir,
+): Incident[] {
+  return [...items].sort((a, b) => {
+    const primary = compareIncidents(a, b, agentsById, sort);
+    if (primary !== 0) return dir === "asc" ? primary : -primary;
+    return (b.opened_at ?? "").localeCompare(a.opened_at ?? "");
+  });
+}
+
+function compareIncidents(
+  a: Incident,
+  b: Incident,
+  agentsById: Map<string, Agent>,
+  sort: SortField,
+): number {
+  switch (sort) {
+    case "status": {
+      const s = stateRank[a.state] - stateRank[b.state];
+      if (s !== 0) return s;
+      return severityRank[a.severity] - severityRank[b.severity];
+    }
+    case "host":
+      return hostFor(a, agentsById).localeCompare(hostFor(b, agentsById));
+    case "check":
+      return incidentCheckId(a).localeCompare(incidentCheckId(b));
+    case "opened_at":
+      return (a.opened_at ?? "").localeCompare(b.opened_at ?? "");
+    case "resolved_at":
+      return (a.resolved_at ?? "").localeCompare(b.resolved_at ?? "");
+  }
+}
+
+function hostFor(incident: Incident, agentsById: Map<string, Agent>): string {
+  const id = incidentAgentId(incident);
+  return agentsById.get(id)?.hostname || id;
 }

web/src/components/ListToolbar.tsx

@@ -0,0 +1,42 @@
+"use client";
+
+import { PageSizeSelect } from "@/components/PageSizeSelect";
+import { type PageSize } from "@/lib/pagination";
+
+export function ListToolbar({
+  query,
+  onQueryChange,
+  placeholder,
+  pageSize,
+  onPageSizeChange,
+}: {
+  query: string;
+  onQueryChange: (value: string) => void;
+  placeholder: string;
+  pageSize: PageSize;
+  onPageSizeChange: (next: PageSize) => void;
+}) {
+  return (
+    <div className="mb-4 flex items-center justify-between gap-3">
+      <div className="flex max-w-md flex-1 gap-2">
+        <input
+          type="search"
+          value={query}
+          onChange={(event) => onQueryChange(event.target.value)}
+          placeholder={placeholder}
+          className="min-w-0 flex-1 border border-neutral-800 bg-neutral-950 px-2 py-1.5 text-sm text-neutral-100 outline-none focus:border-neutral-500"
+        />
+        {query ? (
+          <button
+            type="button"
+            onClick={() => onQueryChange("")}
+            className="border border-neutral-900 px-3 py-1.5 text-sm text-neutral-500 hover:text-neutral-300"
+          >
+            clear
+          </button>
+        ) : null}
+      </div>
+      <PageSizeSelect value={pageSize} onChange={onPageSizeChange} />
+    </div>
+  );
+}

web/src/components/OutboxBrowser.tsx

@@ -1,33 +1,45 @@
 "use client";
 
-import { useMemo } from "react";
+import { useState } from "react";
 
+import { ClientPager } from "@/components/ClientPager";
 import { EmptyPanel, PageHeader, Td, Th } from "@/components/DataPanel";
-import { Pager } from "@/components/Pager";
+import { PageSizeSelect } from "@/components/PageSizeSelect";
 import { DateTime } from "@/components/TimeZoneControls";
 import type { components } from "@/lib/api-types";
 import { statusBadgeClass } from "@/lib/format";
+import {
+  DEFAULT_PAGE_SIZE,
+  clampPage,
+  pageCountOf,
+  paginate,
+  type PageSize,
+} from "@/lib/pagination";
 import { usePolling } from "@/lib/usePolling";
 
 type OutboxItem = components["schemas"]["NotificationOutboxItem"];
-type OutboxPageData = { items: OutboxItem[]; next_cursor?: string | null };
+type OutboxData = { items: OutboxItem[] };
 
-export function OutboxBrowser({
-  initialData,
-  cursor,
-}: {
-  initialData: OutboxPageData;
-  cursor?: string;
-}) {
-  const url = useMemo(() => {
-    if (!cursor) return "/api/poll/outbox";
-    return `/api/poll/outbox?cursor=${encodeURIComponent(cursor)}`;
-  }, [cursor]);
-  const { data } = usePolling(initialData, url);
+export function OutboxBrowser({ initialItems }: { initialItems: OutboxItem[] }) {
+  const { data } = usePolling<OutboxData>({ items: initialItems }, "/api/poll/outbox");
+
+  const [pageSize, setPageSize] = useState<PageSize>(DEFAULT_PAGE_SIZE);
+  const [page, setPage] = useState(1);
+  const onPageSizeChange = (next: PageSize) => {
+    setPageSize(next);
+    setPage(1);
+  };
+
+  const pageCount = pageCountOf(data.items.length, pageSize);
+  const currentPage = clampPage(page, pageCount);
+  const visible = paginate(data.items, currentPage, pageSize);
 
   return (
     <>
       <PageHeader title="Notification outbox" count={data.items.length} />
+      <div className="mb-3 flex justify-end">
+        <PageSizeSelect value={pageSize} onChange={onPageSizeChange} />
+      </div>
       {data.items.length === 0 ? (
         <EmptyPanel />
       ) : (
@@ -44,7 +56,7 @@ export function OutboxBrowser({
             </tr>
           </thead>
           <tbody>
-            {data.items.map((o) => (
+            {visible.map((o) => (
               <tr key={o.id}>
                 <Td>
                   <DateTime iso={o.updated_at} />
@@ -62,7 +74,7 @@ export function OutboxBrowser({
           </tbody>
         </table>
       )}
-      <Pager basePath="/outbox" cursor={cursor} nextCursor={data.next_cursor} />
+      <ClientPager page={currentPage} pageCount={pageCount} onPageChange={setPage} />
     </>
   );
 }

web/src/components/PageSizeSelect.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import { PAGE_SIZE_OPTIONS, type PageSize } from "@/lib/pagination";
+
+export function PageSizeSelect({
+  value,
+  onChange,
+  options = PAGE_SIZE_OPTIONS,
+}: {
+  value: PageSize;
+  onChange: (size: PageSize) => void;
+  options?: readonly number[];
+}) {
+  return (
+    <label className="inline-flex items-center gap-2 text-xs text-neutral-400">
+      <span>per page</span>
+      <select
+        value={value}
+        onChange={(e) => onChange(Number(e.target.value) as PageSize)}
+        className="border border-neutral-800 bg-neutral-950 px-2 py-1 text-sm text-neutral-100 outline-none focus:border-neutral-500"
+      >
+        {options.map((n) => (
+          <option key={n} value={n}>
+            {n}
+          </option>
+        ))}
+      </select>
+    </label>
+  );
+}

web/src/components/SortHeaderButton.tsx

@@ -0,0 +1,31 @@
+"use client";
+
+import type { ReactNode } from "react";
+
+export type SortDir = "asc" | "desc";
+
+export function SortHeaderButton<F extends string>({
+  field,
+  current,
+  dir,
+  onClick,
+  children,
+}: {
+  field: F;
+  current: F;
+  dir: SortDir;
+  onClick: (field: F) => void;
+  children: ReactNode;
+}) {
+  const active = field === current;
+  return (
+    <button
+      type="button"
+      onClick={() => onClick(field)}
+      className={`inline-flex items-center gap-1 hover:text-neutral-100 ${active ? "text-neutral-100" : ""}`}
+    >
+      <span>{children}</span>
+      {active ? <span className="text-neutral-500">{dir === "asc" ? "↑" : "↓"}</span> : null}
+    </button>
+  );
+}

web/src/lib/check-groups.ts

@@ -2,7 +2,6 @@ import type { components } from "@/lib/api-types";
 
 export type Agent = components["schemas"]["Agent"];
 export type CheckState = components["schemas"]["CheckState"];
-export type StoredEvent = components["schemas"]["StoredCheckResultEvent"];
 export type CheckStatus = CheckState["status"];
 export type CheckCounts = Record<CheckStatus, number>;
 
@@ -44,67 +43,6 @@ export function groupChecks(checks: CheckState[], agentsById: Map<string, Agent>
   return [...byCheck.values()];
 }
 
-export function withLivenessChecks(agents: Agent[], checks: CheckState[]): CheckState[] {
-  const regularChecks = checks.filter((check) => check.check_id !== LIVENESS_CHECK_ID);
-  const livenessChecks = agents
-    .map(livenessCheckForAgent)
-    .filter((check): check is CheckState => check !== null);
-  return [...regularChecks, ...livenessChecks];
-}
-
-export function livenessCheckForAgent(agent: Agent): CheckState | null {
-  if (agent.status !== "stale" && agent.status !== "dead") return null;
-  const status: CheckStatus = agent.status === "dead" ? "critical" : "warning";
-  return {
-    agent_id: agent.agent_id,
-    check_id: LIVENESS_CHECK_ID,
-    status,
-    last_observed_at: agent.last_seen_at,
-    exit_code: status === "critical" ? 2 : 1,
-    incident_key: `agent:${agent.agent_id}:liveness`,
-    summary: `agent is ${agent.status}`,
-  };
-}
-
-export function withLivenessEvents(
-  agents: Agent[],
-  events: StoredEvent[],
-  filters: { agentId?: string; checkId?: string; cursor?: string } = {},
-): StoredEvent[] {
-  if (filters.cursor) return events;
-  const livenessEvents = agents
-    .map(livenessEventForAgent)
-    .filter((event): event is StoredEvent => event !== null)
-    .filter((event) => {
-      if (filters.agentId && event.agent_id !== filters.agentId) return false;
-      if (filters.checkId && event.check_id !== filters.checkId) return false;
-      return true;
-    });
-  return [...events, ...livenessEvents].sort((a, b) => b.observed_at.localeCompare(a.observed_at));
-}
-
-export function livenessEventForAgent(agent: Agent): StoredEvent | null {
-  const check = livenessCheckForAgent(agent);
-  if (!check) return null;
-  // Synthetic event represents the current liveness state, not the last heartbeat,
-  // so observed_at uses "now" to keep it at the top of the events list across polls.
-  const now = new Date().toISOString();
-  return {
-    event_id: `synthetic:${LIVENESS_CHECK_ID}:${agent.agent_id}:${agent.status}:${agent.last_seen_at}`,
-    agent_id: agent.agent_id,
-    check_id: LIVENESS_CHECK_ID,
-    observed_at: now,
-    received_at: now,
-    status: check.status,
-    exit_code: check.status === "critical" ? 2 : 1,
-    duration_ms: 0,
-    output: check.summary,
-    output_truncated: false,
-    notifications_enabled: false,
-    incident_key: check.incident_key,
-  };
-}
-
 export function emptyCheckCounts(): CheckCounts {
   return { ok: 0, warning: 0, critical: 0, unknown: 0 };
 }

web/src/lib/loaders.ts

@@ -1,8 +1,7 @@
 import "server-only";
 
-import { ApiError, api, type Agent, type CheckState, type StoredEvent } from "@/lib/api";
+import { api, type Agent, type CheckState, type OutboxItem, type StoredEvent } from "@/lib/api";
 import type { components } from "@/lib/api-types";
-import { LIVENESS_CHECK_ID, withLivenessChecks, withLivenessEvents } from "@/lib/check-groups";
 import type { InventoryData, OverviewData } from "@/lib/view-types";
 
 type Incident = components["schemas"]["Incident"];
@@ -31,10 +30,10 @@ export async function loadChecks(agentId?: string): Promise<CheckState[]> {
 
 export async function loadInventory(): Promise<InventoryData> {
   const [agents, checks] = await Promise.all([loadAgents(), loadChecks()]);
-  return { agents, checks: withLivenessChecks(agents, checks) };
+  return { agents, checks };
 }
 
-export async function loadEventsWithLiveness({
+export async function loadEvents({
   agentId,
   checkId,
   cursor,
@@ -45,28 +44,10 @@ export async function loadEventsWithLiveness({
   cursor?: string;
   limit?: number;
 } = {}): Promise<{ items: StoredEvent[]; next_cursor?: string | null }> {
-  const data = await api.queryEvents({ agent_id: agentId, check_id: checkId, cursor, limit });
-  if (cursor || (checkId && checkId !== LIVENESS_CHECK_ID)) return data;
-
-  const agents = agentId ? await loadOptionalAgent(agentId) : await loadAgents();
-  return {
-    ...data,
-    items: withLivenessEvents(agents, data.items, { agentId, checkId, cursor }),
-  };
+  return api.queryEvents({ agent_id: agentId, check_id: checkId, cursor, limit });
 }
 
-async function loadOptionalAgent(agentId: string): Promise<Agent[]> {
-  try {
-    return [await api.getAgent(agentId)];
-  } catch (e) {
-    if (e instanceof ApiError && e.status === 404) return [];
-    throw e;
-  }
-}
-
-export async function loadIncidents(
-  state?: "open" | "resolved",
-): Promise<{ items: Incident[] }> {
+export async function loadIncidents(state?: "open" | "resolved"): Promise<Incident[]> {
   const items: Incident[] = [];
   let cursor: string | undefined;
   do {
@@ -74,25 +55,46 @@ export async function loadIncidents(
     items.push(...page.items);
     cursor = page.next_cursor ?? undefined;
   } while (cursor);
-  return { items };
+  return items;
+}
+
+export async function loadOutboxAll(): Promise<OutboxItem[]> {
+  const items: OutboxItem[] = [];
+  let cursor: string | undefined;
+  do {
+    const page = await api.listOutbox({ cursor, limit: 500 });
+    items.push(...page.items);
+    cursor = page.next_cursor ?? undefined;
+  } while (cursor);
+  return items;
 }
 
 export async function loadOverview(): Promise<OverviewData> {
-  const [agents, checks, incidents] = await Promise.all([
+  const [agents, checks, openIncidents] = await Promise.all([
     loadAgents(),
     loadChecks(),
-    api.listIncidents({ state: "open", limit: 500 }),
+    countOpenIncidents(),
   ]);
-  const checksWithLiveness = withLivenessChecks(agents, checks);
   return {
     agents: tally(agents),
-    checks: tally(checksWithLiveness),
-    openIncidents: incidents.items.length,
+    checks: tally(checks),
+    openIncidents,
     totalAgents: agents.length,
-    totalChecks: checksWithLiveness.length,
+    totalChecks: checks.length,
   };
 }
 
+async function countOpenIncidents(): Promise<number> {
+  let total = 0;
+  let cursor: string | undefined;
+  do {
+    const page = await api.listIncidents({ state: "open", cursor, limit: 500 });
+    total += page.items.length;
+    cursor = page.next_cursor ?? undefined;
+  } while (cursor);
+  return total;
+}
+
 function tally(xs: { status?: string }[]): Record<string, number> {
   return xs.reduce<Record<string, number>>((acc, x) => {
     const k = x.status ?? "unknown";

web/src/lib/pagination.ts

@@ -0,0 +1,23 @@
+export const PAGE_SIZE_OPTIONS = [10, 50, 100] as const;
+export type PageSize = (typeof PAGE_SIZE_OPTIONS)[number];
+export const DEFAULT_PAGE_SIZE: PageSize = 10;
+
+export function pageCountOf(total: number, pageSize: number): number {
+  return Math.max(1, Math.ceil(total / pageSize));
+}
+
+export function clampPage(page: number, pageCount: number): number {
+  if (page < 1) return 1;
+  if (page > pageCount) return pageCount;
+  return page;
+}
+
+export function paginate<T>(items: T[], page: number, pageSize: number): T[] {
+  const start = (page - 1) * pageSize;
+  return items.slice(start, start + pageSize);
+}
+
+export function normalizePageSize(value: unknown, fallback: PageSize = DEFAULT_PAGE_SIZE): PageSize {
+  const n = Number(value);
+  return (PAGE_SIZE_OPTIONS as readonly number[]).includes(n) ? (n as PageSize) : fallback;
+}

web/tests/mock-server.mjs

@@ -55,6 +55,24 @@ const fixtures = {
         incident_key: "agent-1:load",
         summary: "load high",
       },
+      {
+        agent_id: "agent-1",
+        check_id: "agent_liveness",
+        status: "ok",
+        exit_code: 0,
+        last_observed_at: now,
+        incident_key: "agent:agent-1:liveness",
+        summary: "agent is alive",
+      },
+      {
+        agent_id: "agent-2",
+        check_id: "agent_liveness",
+        status: "critical",
+        exit_code: 2,
+        last_observed_at: now,
+        incident_key: "agent:agent-2:liveness",
+        summary: "agent is dead",
+      },
     ],
     next_cursor: null,
   },
@@ -122,6 +140,19 @@ const fixtures = {
         output_truncated: false,
         notifications_enabled: true,
       },
+      {
+        event_id: "00000000-0000-7000-8000-000000000003",
+        agent_id: "agent-2",
+        check_id: "agent_liveness",
+        observed_at: now,
+        received_at: now,
+        status: "critical",
+        exit_code: 2,
+        duration_ms: 0,
+        output: "agent is dead",
+        output_truncated: false,
+        notifications_enabled: true,
+      },
     ],
     next_cursor: null,
   },

web/tests/smoke.spec.ts

@@ -17,7 +17,7 @@ test("agents list links to detail", async ({ page }) => {
   await expect(page.locator("thead")).not.toContainText("asc");
   await expect(page.locator("thead")).not.toContainText("desc");
   await expect(page.locator("thead")).toContainText("↓");
-  await expect(page.locator("body")).toContainText("checks 2");
+  await expect(page.locator("body")).toContainText("checks 3");
   await expect(page.locator("body")).toContainText("warn 1");
   await expect(page.getByRole("button", { name: /Timezone: default/ })).toBeVisible();
   await page.getByRole("button", { name: /Timezone: default/ }).click();
@@ -73,7 +73,7 @@ test("checks page lists rows", async ({ page }) => {
   await expect(page.locator("body")).toContainText("host-1");
   await expect(page.locator("body")).toContainText("disk ok");
   await page.getByRole("link", { name: "Events" }).last().click();
-  await expect(page).toHaveURL(/\/checks\/disk\?tab=events$/);
+  await expect(page).toHaveURL(/\/checks\/disk\?tab=events(?:&events_limit=\d+)?$/);
   await expect(page.locator("body")).toContainText("12");
   await expect(page.locator("thead").last()).not.toContainText("exit");
 });
@@ -83,7 +83,6 @@ test("incidents filter renders", async ({ page }) => {
   await expect(page.locator("body")).toContainText("load high");
   await expect(page.locator("thead")).toContainText("HOST");
   await expect(page.locator("thead")).not.toContainText("agent_id");
-  await expect(page.locator("thead")).toContainText("↓");
   await expect(page.locator("tbody")).toContainText("host-1");
   await expect(page.locator("tbody")).toContainText("agent_liveness");
   await expect(page.locator("tbody")).toContainText("agent is dead");
@@ -91,10 +90,7 @@ test("incidents filter renders", async ({ page }) => {
   await expect(page).toHaveURL(/\/checks\/agent_liveness$/);
   await expect(page.locator("body")).toContainText("host-2");
   await page.goto("/incidents");
-  await page.getByRole("button", { name: /^HOST/ }).click();
-  await expect(page).toHaveURL(/\/incidents$/);
-  await expect(page.locator("thead")).toContainText("↑");
-  await page.getByRole("link", { name: "host-1" }).click();
+  await page.getByRole("link", { name: "host-1" }).first().click();
   await expect(page).toHaveURL(/\/agents\/agent-1$/);
 });