feat(mcp): SNMP devices and Prometheus targets: their state, readings and series (#5840)

The snmp plugin registers list_snmp_devices and get_snmp_device; the
prometheus plugin registers list_prometheus_targets and
get_prometheus_target. Both are viewer-level, read what the poller and
scraper stored, and exist only while their plugin is enabled.
get_overview names a device or target whose last poll or scrape failed;
stale, pending and off are left out.

A device's community and v3 keys and a target's token are never
returned, and a password in a target URL is masked.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/core/mcp.md

@@ -82,6 +82,8 @@ Each role includes the tools of the roles above it in this list.
 | Host agent (built in, always on) | `list_agents`, `list_maintenance_plans` (each plan's group, weekly slot, next run and latest run: how far it got, who it skipped and why), `get_maintenance_job` (a host's update jobs or one job: state, packages updated, whether it rebooted, why it failed) |
 | Traefik plugin | `list_routers` (each router graded as the Traefik page grades it, with the status codes behind a problem, what they mean and the swarm service behind it), `get_router` (one router's history, codes, normal and anomalies), `list_certificates` (served certificates, days left, the routers they cover), `get_traffic` (the access log's clients, countries and routers, and Traefik's own figures) |
 | UniFi plugin | `get_network` (the WAN, clients, Wi-Fi networks, speed tests and devices by status), `list_devices`, `list_clients` (everyone seen, or the newest poll's top talkers), `list_network_events`, `list_alarms`, `get_network_config` (networks and VLANs, port forwards, firewall rules) |
+| SNMP plugin | `list_snmp_devices` (each device's state, newest readings in their units and the readings it didn't return), `get_snmp_device` (one device's readings over a range). Never the community or v3 keys |
+| Prometheus plugin | `list_prometheus_targets` (each target's state and its newest scrape: series kept, dropped and over the cap), `get_prometheus_target` (a target's stored series by metric, with labels and newest values). Never the token, and a password in a URL is masked |
 
 ### Operator: run playbooks, change monitoring
 

plugins/prometheus/__init__.py

@@ -68,3 +68,13 @@ def get_audit_entities() -> dict:
     from .models import PrometheusTarget, PrometheusWidgetTemplate
     return {"prometheus_target": (PrometheusTarget, "/plugins/prometheus/targets/{}"),
             "prometheus_template": (PrometheusWidgetTemplate, "/plugins/prometheus/templates/custom:{}")}
+
+
+def register_mcp_tools(register) -> None:
+    from .mcp_tools import register_tools
+    register_tools(register)
+
+
+async def mcp_overview(db) -> list[dict]:
+    from .mcp_tools import mcp_overview as findings
+    return await findings(db)

plugins/prometheus/mcp_tools.py

@@ -0,0 +1,114 @@
+"""The prometheus plugin's MCP tools and its get_overview findings (#5840).
+
+Registered through register_mcp_tools() in __init__.py, so they exist only
+while the plugin is enabled. They read what the scraper stored; nothing
+reaches a target, and a target's bearer token (or a password in its URL)
+is never returned.
+"""
+from __future__ import annotations
+
+from sqlalchemy import select
+
+from steward.core.metric_series import latest_values
+from steward.mcp.tools._shape import age_s, bounded, clamp_limit, db_session, iso, now_utc, pick, redact_url
+from steward.mcp.tools.overview import finding
+from steward.models.metrics import PluginMetricLatest
+from steward.models.users import UserRole
+
+from .models import PrometheusTarget
+from .routes import group_series
+from .service import OWN_METRICS, SOURCE, target_state
+
+REACHES = ("down", "stale", "pending", "up", "off")
+_ORDER = {r: i for i, r in enumerate(REACHES)}
+
+
+def _target_view(t: PrometheusTarget, own: dict, now) -> dict:
+    state = target_state(t, now)
+    return {"target_id": t.id, "name": t.name, "url": redact_url(t.url), "enabled": t.enabled,
+            "reach": state.reach, "says": state.says, "interval_s": t.interval_seconds,
+            "scraped_at": iso(t.last_scraped_at), "ok_at": iso(t.last_ok_at), "ok_age_s": age_s(t.last_ok_at, now),
+            "series_kept": t.last_kept, "series_dropped": t.last_dropped, "series_capped": t.last_capped,
+            "series_cap": t.series_cap, "keep": list(t.keep or []), "drop": list(t.drop or []),
+            "scrape_ms": own.get("scrape_ms")}
+
+
+async def list_prometheus_targets() -> dict:
+    """The /metrics endpoints Steward scrapes, not answering first.
+
+    `reach`: "down" (the last scrape failed; `says` is why), "stale" (not
+    scraped recently), "pending", "up" or "off". `series_kept` /
+    `series_dropped` count the newest scrape's series the keep/drop patterns
+    let through or left out; `series_capped` those past `series_cap`, which
+    were not stored. get_prometheus_target lists a target's series;
+    query_metrics(source_module="prometheus", resource=…, metric=…) reads
+    one's history.
+    """
+    now = now_utc()
+    async with db_session() as db:
+        targets = list((await db.execute(select(PrometheusTarget).order_by(PrometheusTarget.name))).scalars())
+        rows = (await db.execute(select(PluginMetricLatest).where(
+            PluginMetricLatest.source_module == SOURCE,
+            PluginMetricLatest.resource_name.in_([t.name for t in targets] or [""]),
+            PluginMetricLatest.metric_name == "scrape_ms"))).scalars()
+        own = {r.resource_name: {"scrape_ms": r.value} for r in rows}
+    views = [_target_view(t, own.get(t.name, {}), now) for t in targets]
+    views.sort(key=lambda v: (_ORDER[v["reach"]], v["name"].lower()))
+    return {"targets": views}
+
+
+async def get_prometheus_target(target: str, search: str = "", limit: int = 100) -> dict:
+    """One target's stored series, grouped by metric name, each with the
+    labels that tell its series apart and the newest value in its unit.
+
+    target: its name or id (list_prometheus_targets).
+    search: part of a metric name; empty for all.
+    limit: metric groups to return, default 100, max 500.
+
+    A state set (a series per state, one of them 1) is folded to the
+    current state. `resource` is what query_metrics takes for a series'
+    history (source_module "prometheus").
+    """
+    now = now_utc()
+    async with db_session() as db:
+        t = pick(target, list((await db.execute(select(PrometheusTarget))).scalars()),
+                 kind="Prometheus target", list_tool="list_prometheus_targets")
+        latest = await latest_values(db, SOURCE, t.name, include_children=True)
+    own = {r.metric_name: r.value for r in latest if r.resource_name == t.name and r.metric_name in OWN_METRICS}
+    groups = group_series(t.name, latest)
+    if search:
+        groups = [g for g in groups if search.lower() in g["metric"].lower()]
+
+    def row(r: dict, states: bool) -> dict:
+        if states:
+            return {"labels": r["labels"], "resource": r["resource"], "state": r["text"], "states": r["states"]}
+        return {"labels": r["labels"], "resource": r["resource"], "value": r["value"],
+                "shown": r["text"] or iso(r["moment"]), "at": iso(r["at"])}
+
+    shaped = [{"metric": g["metric"], "series": [row(r, g["states"]) for r in g["rows"][:50]],
+               **({"more_series": len(g["rows"]) - 50} if len(g["rows"]) > 50 else {})} for g in groups]
+    out = {"target": _target_view(t, own, now)}
+    out.update(bounded(shaped, clamp_limit(limit, 100, 500), key="metrics",
+                       more="Pass a `search`, or a larger `limit`."))
+    return out
+
+
+def target_findings(views: list[dict]) -> list[dict]:
+    """A target whose last scrape failed. Stale and off are the plugin or
+    the admin's choice, not the endpoint, so they are left out."""
+    return [finding("warning", "prometheus_target_down", v["name"],
+                    f"Prometheus target {v['name']} isn't answering: {v['says']}",
+                    since=v["_ok_at"], ids={"target_id": v["target_id"]},
+                    next=f'get_prometheus_target(target="{v["name"]}")')
+            for v in views if v["reach"] == "down"]
+
+
+async def mcp_overview(db) -> list[dict]:
+    now = now_utc()
+    targets = list((await db.execute(select(PrometheusTarget))).scalars())
+    return target_findings([_target_view(t, {}, now) | {"_ok_at": t.last_ok_at} for t in targets])
+
+
+def register_tools(register) -> None:
+    for fn in (list_prometheus_targets, get_prometheus_target):
+        register(fn, role=UserRole.viewer, read_only=True)

plugins/snmp/__init__.py

@@ -39,3 +39,13 @@ def get_audit_entities() -> dict:
     """Audit rows about a device name it and link to its page."""
     from .models import SnmpDevice
     return {"snmp_device": (SnmpDevice, "/plugins/snmp/devices/{}")}
+
+
+def register_mcp_tools(register) -> None:
+    from .mcp_tools import register_tools
+    register_tools(register)
+
+
+async def mcp_overview(db) -> list[dict]:
+    from .mcp_tools import mcp_overview as findings
+    return await findings(db)

plugins/snmp/mcp_tools.py

@@ -0,0 +1,105 @@
+"""The snmp plugin's MCP tools and its get_overview findings (#5840).
+
+Registered through register_mcp_tools() in __init__.py, so they exist only
+while the plugin is enabled. They read what the poller stored; nothing asks a
+device anything, and a device's community and v3 keys are never returned.
+"""
+from __future__ import annotations
+
+from sqlalchemy import select
+
+from steward.core.metric_series import points
+from steward.mcp._context import mcp_app
+from steward.mcp.tools._shape import age_s, db_session, iso, lookback, now_utc, pick, summarize
+from steward.mcp.tools.overview import finding
+from steward.models.users import UserRole
+
+from .models import SnmpDevice
+from .readings import stored_unit
+from .routes import _latest, shown_readings
+from .service import device_state, readings_for
+
+REACHES = ("down", "stale", "pending", "up")
+_ORDER = {r: i for i, r in enumerate(REACHES)}
+
+
+def _poll_seconds() -> int:
+    return int(mcp_app().config["PLUGINS"]["snmp"].get("poll_interval_seconds", 60))
+
+
+def _device_view(d: SnmpDevice, values: dict, now, poll: int) -> dict:
+    state = device_state(d, poll, now)
+    names = {r.key: r.name for r in readings_for(d)}
+    return {"device_id": d.id, "name": d.name, "address": d.address, "port": d.port, "version": d.version,
+            "host_id": d.host_id, "reach": state.reach, "says": state.says,
+            "polled_at": iso(d.last_polled_at), "ok_at": iso(d.last_ok_at), "ok_age_s": age_s(d.last_ok_at, now),
+            "readings": [{"key": r["key"], "name": r["name"], "value": r["text"], "counter": r["counter"]}
+                         for r in shown_readings(d, values)],
+            "missing": [names.get(k, k) for k in d.missing or []]}
+
+
+async def list_snmp_devices(reach: str = "") -> dict:
+    """The devices Steward polls over SNMP (switches, UPSes, printers, NAS
+    boxes), not answering first.
+
+    reach: "down" (the last poll failed; `says` is why), "stale" (not polled
+      recently: the plugin may be off), "pending" (never polled), "up"; empty
+      for all.
+
+    Each device gives its newest readings in their units (counters as
+    rates), and `missing`: readings it is configured for that the device
+    didn't return. get_snmp_device gives a device's history.
+    """
+    if reach and reach not in REACHES:
+        raise ValueError(f"reach must be one of {', '.join(REACHES)}, or empty for all.")
+    now, poll = now_utc(), _poll_seconds()
+    async with db_session() as db:
+        devices = list((await db.execute(select(SnmpDevice).order_by(SnmpDevice.name))).scalars())
+        values = await _latest(db, [d.name for d in devices])
+    rows = sorted((_device_view(d, values.get(d.name, {}), now, poll) for d in devices),
+                  key=lambda v: (_ORDER[v["reach"]], v["name"].lower()))
+    return {"devices": [r for r in rows if not reach or r["reach"] == reach], "total": len(rows)}
+
+
+async def get_snmp_device(device: str, range: str = "24h") -> dict:
+    """One SNMP device: its state, newest readings, and each reading's
+    history over `range` (min/avg/max/last and ≤60 points, in the unit the
+    reading is stored in: `unit`).
+
+    device: its name or id (list_snmp_devices).
+    range: "1h", "6h", "24h" (default), "7d" or "30d".
+    """
+    since, key = lookback(range)
+    now, poll = now_utc(), _poll_seconds()
+    async with db_session() as db:
+        devices = list((await db.execute(select(SnmpDevice))).scalars())
+        d = pick(device, devices, kind="SNMP device", list_tool="list_snmp_devices")
+        values = (await _latest(db, [d.name])).get(d.name, {})
+        history = {r.key: (stored_unit(r), await points(db, "snmp", d.name, r.key, since))
+                   for r in readings_for(d)}
+    out = _device_view(d, values, now, poll)
+    out["range"] = key
+    out["history"] = {k: {"unit": unit, **summarize(pts)} for k, (unit, pts) in history.items()}
+    return out
+
+
+def device_findings(views: list[dict]) -> list[dict]:
+    """A device whose last poll failed. A stale one is the plugin or poller,
+    not the device, so it is left out."""
+    return [finding("warning", "snmp_device_down", v["name"],
+                    f"SNMP device {v['name']} ({v['address']}) isn't answering: {v['says']}",
+                    since=v["_ok_at"], ids={"device_id": v["device_id"]},
+                    next=f'get_snmp_device(device="{v["name"]}")')
+            for v in views if v["reach"] == "down"]
+
+
+async def mcp_overview(db) -> list[dict]:
+    now, poll = now_utc(), _poll_seconds()
+    devices = list((await db.execute(select(SnmpDevice))).scalars())
+    views = [_device_view(d, {}, now, poll) | {"_ok_at": d.last_ok_at} for d in devices]
+    return device_findings(views)
+
+
+def register_tools(register) -> None:
+    for fn in (list_snmp_devices, get_snmp_device):
+        register(fn, role=UserRole.viewer, read_only=True)

tests/plugins/prometheus/test_mcp_tools.py

@@ -0,0 +1,47 @@
+"""The prometheus plugin's MCP tools (#5840): which targets the overview
+names, what a target row carries (never its token or a password in its URL),
+and the tools it registers."""
+from datetime import datetime, timedelta, timezone
+from types import SimpleNamespace as NS
+
+import plugins.prometheus as prometheus_plugin
+from plugins.prometheus import mcp_tools as t
+from steward.models.users import UserRole
+
+NOW = datetime(2026, 10, 15, 12, 0, tzinfo=timezone.utc)
+
+
+def _target(name, *, enabled=True, scraped=timedelta(seconds=30), error=None,
+            url="http://archives:8080/metrics"):
+    return NS(id=f"id-{name}", name=name, url=url, token="bearer-s3cret", enabled=enabled,
+              interval_seconds=60, last_scraped_at=NOW - scraped if scraped else None,
+              last_ok_at=NOW - timedelta(hours=1), last_error=error, last_kept=120, last_dropped=30,
+              last_capped=0, series_cap=1000, keep=["archives_*"], drop=[])
+
+
+def test_only_a_target_whose_scrape_failed_is_an_overview_finding():
+    views = [t._target_view(x, {}, NOW) | {"_ok_at": x.last_ok_at} for x in (
+        _target("archives", error="connection refused"), _target("fine"),
+        _target("off", enabled=False, error="connection refused"),
+        _target("stale", scraped=timedelta(days=1), error="connection refused"),
+        _target("new", scraped=None))]
+    [f] = t.target_findings(views)
+    assert f["kind"] == "prometheus_target_down" and f["subject"] == "archives"
+    assert "connection refused" in f["summary"] and f["next"] == 'get_prometheus_target(target="archives")'
+
+
+def test_a_target_row_never_carries_its_token_or_url_password():
+    row = t._target_view(_target("archives", url="http://scrape:hunter2@archives:8080/metrics"),
+                         {"scrape_ms": 42.0}, NOW)
+    text = repr(row)
+    assert "bearer-s3cret" not in text and "hunter2" not in text
+    assert row["url"] == "http://scrape:***@archives:8080/metrics"
+    assert row["scrape_ms"] == 42.0 and row["series_kept"] == 120 and row["reach"] == "up"
+
+
+def test_the_plugin_registers_its_tools_for_viewers():
+    got = {}
+    prometheus_plugin.register_mcp_tools(lambda fn, role, read_only: got.update({fn.__name__: (role, read_only)}))
+    assert got == {name: (UserRole.viewer, True)
+                   for name in ("list_prometheus_targets", "get_prometheus_target")}
+    assert callable(prometheus_plugin.mcp_overview)

tests/plugins/snmp/test_mcp_tools.py

@@ -0,0 +1,49 @@
+"""The snmp plugin's MCP tools (#5840): which devices the overview names, what
+a device row carries (never its community or v3 keys), and the tools it
+registers."""
+from datetime import datetime, timedelta, timezone
+from types import SimpleNamespace as NS
+
+import pytest
+
+import plugins.snmp as snmp_plugin
+from plugins.snmp import mcp_tools as t
+from steward.models.users import UserRole
+
+NOW = datetime(2026, 10, 15, 12, 0, tzinfo=timezone.utc)
+
+
+def _device(name, *, polled=timedelta(seconds=30), error=None):
+    return NS(id=f"id-{name}", name=name, address="10.0.0.9", port=161, version="2c",
+              community="s3cret", v3_user="", v3_auth_key="authkey", v3_priv_key="privkey",
+              presets=[], interfaces="", custom=None, host_id=None,
+              last_polled_at=NOW - polled if polled else None, last_ok_at=NOW - timedelta(hours=1),
+              last_error=error, missing=[])
+
+
+def test_only_a_device_whose_poll_failed_is_an_overview_finding():
+    views = [t._device_view(d, {}, NOW, 60) | {"_ok_at": d.last_ok_at} for d in (
+        _device("ups", error="Timed out"), _device("switch"),
+        _device("printer", polled=timedelta(days=1), error="Timed out"), _device("nas", polled=None))]
+    [f] = t.device_findings(views)
+    assert f["kind"] == "snmp_device_down" and f["subject"] == "ups" and "Timed out" in f["summary"]
+    assert f["next"] == 'get_snmp_device(device="ups")'
+
+
+def test_a_device_row_never_carries_its_secrets():
+    row = t._device_view(_device("ups"), {}, NOW, 60)
+    text = repr(row)
+    assert "s3cret" not in text and "authkey" not in text and "privkey" not in text
+    assert row["reach"] == "up" and row["device_id"] == "id-ups"
+
+
+def test_the_plugin_registers_its_tools_for_viewers():
+    got = {}
+    snmp_plugin.register_mcp_tools(lambda fn, role, read_only: got.update({fn.__name__: (role, read_only)}))
+    assert got == {name: (UserRole.viewer, True) for name in ("list_snmp_devices", "get_snmp_device")}
+    assert callable(snmp_plugin.mcp_overview)
+
+
+async def test_list_snmp_devices_refuses_an_unknown_reach():
+    with pytest.raises(ValueError, match="reach must be one of"):
+        await t.list_snmp_devices(reach="broken")