phase: 01_severity_language

**Gate defect found & fixed (the "does not lint" bug).** `.agents/validate.sh` — the phase gate — ran `python3 -m pytest` on `/usr/bin/python3` + `~/.local` site-packages (not the uv venv), ran `ruff check .` *only if* a ruff happened to be on PATH, and **never ran pyright or the coverage floor**. Rewrote it to the project's real gate: cd to repo root → `uv run pytest --cov --cov-fail-under=94` → `uv run ruff check src tests agent` → `uv run pyright` → `node --check web/static/*.js` → hygiene gates; a missing toolchain now fails loudly. Provoked it to confirm it bites (floor + a seeded F401 both fail).

**Verification (all green)**
- `bash .agents/validate.sh` → **exit 0**: 356 passed, 6 skipped · coverage **94.75%** (floor 94) · ruff `All checks passed!` · pyright `0 errors` · node syntax clean
- `uv run pytest --cov` → `severity.py` **100%**; `uv run pytest -m live --live` → **6 passed**; `uv pip list --outdated` → empty
- Criteria: `classify('cpu.usage_pct',…)` → `fail`/`ok`/`None` ✓ · `/api/ups/snapshot` carries `severity` beside `charge_pct`/`load_pct`/`battery_runtime` (apc now live-`warn` at 498 s — threshold working) ✓ · no `.sev-*`/synonym vocabulary (only a comment saying so) ✓ · pytest/coverage/lint ✓ · dev server restarted, `/api/health` ok 6/6 sources, all pages+assets 200 ✓
- Chromium against live fleet: `severityFrom` cell→`fail`, bare→`warn`, null→`''`, unrated→`''`; `hero` fail → `rgb(207,34,46)`, null → `n/a` with **no** verdict class, warn+bar 42%; all four pages render unchanged → `data/logs/phase01-final-{index,system,llm,ups}.png`

**Docs (full review, incl. pre-existing drift).** README: `/ups` row claimed "upsd on 3493" (fleet is 3051, stated elsewhere in the same file); config table omitted `DASH_HOST/PORT`, llm/ups `*_INTERVAL_SECONDS`, `*_TIMEOUT_SECONDS`, `GUFO/VLLM_API_KEY`, `POLL_MS_*`, `DEBUGPY` (+ dedup); severity bullet omitted `disks`/`gpus[]`/rated LLM cells and the ratio rescale; agent section listed only `/snapshot` though `/info`+`/health` exist. AGENTS.md: same 3493 claim; `install-agent.sh --token-file` (its flags are `--bind/--port/--token/--rotate-token/--status/--uninstall` — it hands *the agent* `--token-file`); gap 3 "Two commits" (now 6, still no `origin`); gap 1 given the sudoers install command + verified live gating reason; coverage line now 80% repo floor vs 94% gate floor; cyberpower `identity.model: GX1500U` vs `ups.description` quirk. `.env.dev.example`: `DEV_FORWARDS` remote port 3493→3051 and engine URLs that pointed at `127.0.0.1` with nothing forwarding them.

**Deviations.** No `ruff format` (30 files would reformat; the project gate is `ruff check` + pyright — reformatting completed phases is out of scope). **No live-infra changes**: enabling the battery-test buttons needs `deploy/nut-sudoers` installed on driveripper + a nut-server restart and a scoped `[dashboards]` `instcmds` user — prod write with a documented shutdown risk (AGENTS gap 1), so repo-side only. 36 pre-existing `ResourceWarning: unclosed database` from test fixtures are noise, not failures; left rather than churn ~15 fixtures. `severity.attach()` is unit-tested but has no production call site until phases 02–05.

**Next pending phase:** `02_overview_fleet_and_alerts` (`01_alerts_builder.md`).

tests/test_nut.py

@@ -435,6 +435,61 @@ def test_payload_carries_numbers_health_and_what_the_driver_offers() -> None:
     assert payload["extra"] or payload["status"] == "OL CHRG"
 
 
+def test_payload_severity_colours_the_hero_battery_numbers() -> None:
+    """charge / load / runtime carry the verdict so the page paints a class, not a threshold."""
+    payload = nut.payload(reading(), now=1_767_225_600.0)   # charge 100, runtime 3720 s, load 34 %
+    assert payload["severity"] == {"charge_pct": "ok", "load_pct": "ok", "battery_runtime": "ok"}
+    # the verdict sits beside the numbers; it does not replace or rename any of them
+    assert payload["numbers"]["charge_pct"] == 100.0
+    assert payload["numbers"]["battery_runtime"] == 3720.0
+
+
+@pytest.mark.parametrize("overrides,expected", [
+    ({"battery.charge": "15"}, {"charge_pct": "fail"}),
+    ({"battery.charge": "50"}, {"charge_pct": "warn"}),      # reaching warn trips it
+    ({"battery.charge": "50.1"}, {"charge_pct": "ok"}),
+    ({"battery.runtime": "240"}, {"battery_runtime": "fail"}),
+    ({"battery.runtime": "600"}, {"battery_runtime": "warn"}),
+    ({"ups.load": "95"}, {"load_pct": "fail"}),
+    ({"ups.load": "70"}, {"load_pct": "warn"}),
+])
+def test_severity_trips_the_ratified_ups_thresholds(overrides, expected) -> None:
+    payload = nut.payload(reading(**overrides), now=1_767_225_600.0)
+    for key, verdict in expected.items():
+        assert payload["severity"][key] == verdict, f"{key} with {overrides}"
+
+
+def test_severity_is_null_when_the_driver_publishes_nothing() -> None:
+    """Neither real UPS reports a battery temperature and either can drop `battery.runtime`;
+    an absent number gets no colour, and the health check keeps saying `unknown`."""
+    values = {key: value for key, value in VAR_ROWS.items()
+              if key not in ("battery.runtime", "battery.temperature")}
+    payload = nut.payload(nut.UpsReading(name="apc", vars=values, commands=[]),
+                          now=1_767_225_600.0)
+    assert payload["numbers"]["battery_runtime"] is None
+    assert payload["severity"]["battery_runtime"] is None
+    assert payload["numbers"]["battery_temperature"] is None
+    temp = next(c for c in payload["health"]["checks"] if c["name"] == "Battery temperature")
+    assert temp["status"] == "unknown", "severity is additive: assess() keeps its own judgement"
+
+
+def test_severity_does_not_touch_health_checks_or_numbers() -> None:
+    ups = reading()
+    payload = nut.payload(ups, now=1_767_225_600.0)
+    assert all(check["status"] in ("ok", "warn", "fail", "unknown")
+               for check in payload["health"]["checks"])
+    assert payload["health"] == nut.assess(ups, now=1_767_225_600.0), \
+        "the condition verdict and the value verdict must not contaminate each other"
+
+
+async def test_simulated_ups_cards_carry_severity_too() -> None:
+    """The UPS page is developable without a battery, and still gets real verdicts."""
+    for ups in await NutSimulator().read():
+        card = nut.payload(ups, now=1_767_225_600.0)
+        assert set(card["severity"]) == {"charge_pct", "load_pct", "battery_runtime"}
+        assert card["severity"]["charge_pct"] == "ok", "the sim starts at float charge"
+
+
 def test_history_samples_only_include_real_numbers() -> None:
     values = {key: value for key, value in VAR_ROWS.items() if key != "battery.runtime"}
     samples = nut.history_samples(nut.UpsReading(name="cyberpower", vars=values, commands=[]))