Flag weak Wi-Fi in device health checks

packages/cli/tests/devices-triage.test.ts

@@ -43,7 +43,7 @@ function makeDevice(overrides: Partial<Device> & { serial: string }): Device {
 		status: overrides.status ?? null,
 		battery: overrides.battery ?? null,
 		batteryState: null,
-		wifiStrength: null,
+		wifiStrength: overrides.wifiStrength ?? null,
 		firmware: null,
 		color: null,
 		thumbnail: null,
@@ -387,6 +387,32 @@ describe("devices --critical", () => {
 		expect(parsed[0].health).toBeDefined();
 		expect(parsed[0].health.overall).toBe("warning");
 	});
+
+	it("keeps weak Wi-Fi devices in JSON mode", async () => {
+		const goodDevice = makeDevice({ serial: "GOOD", label: "Healthy", status: "online" });
+		const weakWifiDevice = makeDevice({
+			serial: "WIFI",
+			label: "WeakWifi",
+			status: "online",
+			wifiStrength: -78,
+		});
+
+		mockGetDevices.mockResolvedValue([goodDevice, weakWifiDevice]);
+		mockGetAllDeviceChannels.mockResolvedValue([
+			makeChannel({ value: 200, units: "F", number: "1" }),
+		]);
+
+		const { devices } = await import("../src/commands/devices.js");
+		await devices({ json: true, criticalOnly: true });
+
+		const raw = logSpy.mock.calls[0][0] as string;
+		const parsed = JSON.parse(raw);
+		expect(parsed).toHaveLength(1);
+		expect(parsed[0].serial).toBe("WIFI");
+		expect(parsed[0].health.issues).toContainEqual(
+			expect.objectContaining({ code: "weak_wifi_signal", severity: "warning" }),
+		);
+	});
 });
 
 // =============================================================================

packages/sdk/src/device-health.ts

@@ -8,6 +8,40 @@ const STALE_CRITICAL_MS = 30 * 60 * 1000;
 const BATTERY_WARNING_THRESHOLD = 20;
 /** Battery percentage below which a critical issue is issued. */
 const BATTERY_CRITICAL_THRESHOLD = 5;
+/** RSSI at or below this dBm is warning-level Wi-Fi health. */
+const WIFI_WARNING_DBM = -75;
+/** RSSI at or below this dBm is critical Wi-Fi health. */
+const WIFI_CRITICAL_DBM = -85;
+/** Percentage at or below this value is warning-level Wi-Fi health. */
+const WIFI_WARNING_PERCENT = 30;
+/** Percentage at or below this value is critical Wi-Fi health. */
+const WIFI_CRITICAL_PERCENT = 10;
+
+function assessWifiStrength(strength: number): DeviceHealthIssue | null {
+	const isRssi = strength < 0;
+	const detail = isRssi ? `RSSI ${strength} dBm` : `Signal ${strength}%`;
+	const critical = isRssi ? strength <= WIFI_CRITICAL_DBM : strength <= WIFI_CRITICAL_PERCENT;
+	if (critical) {
+		return {
+			code: "weak_wifi_signal",
+			severity: "critical",
+			message: "Wi-Fi signal critically weak",
+			detail,
+		};
+	}
+
+	const warning = isRssi ? strength <= WIFI_WARNING_DBM : strength <= WIFI_WARNING_PERCENT;
+	if (warning) {
+		return {
+			code: "weak_wifi_signal",
+			severity: "warning",
+			message: "Wi-Fi signal weak",
+			detail,
+		};
+	}
+
+	return null;
+}
 
 /**
  * Assess the health of a device based on its state and channel data.
@@ -80,6 +114,11 @@ export function assessDeviceHealth(
 		}
 	}
 
+	if (device.wifiStrength != null) {
+		const wifiIssue = assessWifiStrength(device.wifiStrength);
+		if (wifiIssue) issues.push(wifiIssue);
+	}
+
 	// Offline check
 	if (device.status !== "online") {
 		issues.push({

packages/sdk/src/types.ts

@@ -472,7 +472,12 @@ export interface DeviceHealth {
 
 /** A single health issue detected on a device. */
 export interface DeviceHealthIssue {
-	readonly code: "stale_reading" | "low_battery" | "offline" | "firmware_outdated";
+	readonly code:
+		| "stale_reading"
+		| "low_battery"
+		| "weak_wifi_signal"
+		| "offline"
+		| "firmware_outdated";
 	readonly severity: "warning" | "critical";
 	readonly message: string;
 	readonly detail?: string;

packages/sdk/tests/device-health.test.ts

@@ -168,6 +168,53 @@ describe("assessDeviceHealth", () => {
 		);
 	});
 
+	it("returns warning for weak RSSI", () => {
+		const now = new Date("2026-01-01T12:00:00Z");
+		const device = makeDevice({ lastSeen: now, status: "online", wifiStrength: -78 });
+		const channels = [makeChannel({ lastSeen: now })];
+
+		const result = assessDeviceHealth(device, channels, now);
+
+		expect(result.overall).toBe("warning");
+		expect(result.issues).toContainEqual(
+			expect.objectContaining({
+				code: "weak_wifi_signal",
+				severity: "warning",
+				detail: "RSSI -78 dBm",
+			}),
+		);
+	});
+
+	it("returns critical for very weak RSSI", () => {
+		const now = new Date("2026-01-01T12:00:00Z");
+		const device = makeDevice({ lastSeen: now, status: "online", wifiStrength: -88 });
+		const channels = [makeChannel({ lastSeen: now })];
+
+		const result = assessDeviceHealth(device, channels, now);
+
+		expect(result.overall).toBe("critical");
+		expect(result.issues).toContainEqual(
+			expect.objectContaining({ code: "weak_wifi_signal", severity: "critical" }),
+		);
+	});
+
+	it("returns warning for low percentage Wi-Fi signal", () => {
+		const now = new Date("2026-01-01T12:00:00Z");
+		const device = makeDevice({ lastSeen: now, status: "online", wifiStrength: 25 });
+		const channels = [makeChannel({ lastSeen: now })];
+
+		const result = assessDeviceHealth(device, channels, now);
+
+		expect(result.overall).toBe("warning");
+		expect(result.issues).toContainEqual(
+			expect.objectContaining({
+				code: "weak_wifi_signal",
+				severity: "warning",
+				detail: "Signal 25%",
+			}),
+		);
+	});
+
 	it("derives overall from worst severity", () => {
 		const now = new Date("2026-01-01T12:00:00Z");
 		// Offline (warning) + critical battery

packages/vscode/tests/tree-health.test.ts

@@ -177,6 +177,14 @@ describe("DeviceNode health display", () => {
 		expect(node.description).toContain("Warning");
 	});
 
+	it("shows warning description for weak Wi-Fi", () => {
+		const device = makeDevice({ status: "online", battery: 80, wifiStrength: -78 });
+		const channels = [makeChannel()];
+		const node = new DeviceNode(device, false, false, channels);
+
+		expect(node.description).toContain("Warning");
+	});
+
 	it("shows no health indicator when all is well", () => {
 		const device = makeDevice({ status: "online", battery: 80 });
 		const channels = [makeChannel()];

packages/web/src/components/DeviceHealthBadge.tsx

@@ -10,6 +10,40 @@ const STALE_CRITICAL_MS = 30 * 60 * 1000;
 const BATTERY_WARNING_THRESHOLD = 20;
 /** Battery percentage below which a critical issue is issued. */
 const BATTERY_CRITICAL_THRESHOLD = 5;
+/** RSSI at or below this dBm is warning-level Wi-Fi health. */
+const WIFI_WARNING_DBM = -75;
+/** RSSI at or below this dBm is critical Wi-Fi health. */
+const WIFI_CRITICAL_DBM = -85;
+/** Percentage at or below this value is warning-level Wi-Fi health. */
+const WIFI_WARNING_PERCENT = 30;
+/** Percentage at or below this value is critical Wi-Fi health. */
+const WIFI_CRITICAL_PERCENT = 10;
+
+function assessWifiStrength(strength: number): DeviceHealth["issues"][number] | null {
+	const isRssi = strength < 0;
+	const detail = isRssi ? `RSSI ${strength} dBm` : `Signal ${strength}%`;
+	const critical = isRssi ? strength <= WIFI_CRITICAL_DBM : strength <= WIFI_CRITICAL_PERCENT;
+	if (critical) {
+		return {
+			code: "weak_wifi_signal",
+			severity: "critical",
+			message: "Wi-Fi signal critically weak",
+			detail,
+		};
+	}
+
+	const warning = isRssi ? strength <= WIFI_WARNING_DBM : strength <= WIFI_WARNING_PERCENT;
+	if (warning) {
+		return {
+			code: "weak_wifi_signal",
+			severity: "warning",
+			message: "Wi-Fi signal weak",
+			detail,
+		};
+	}
+
+	return null;
+}
 
 /**
  * Browser-local implementation of health assessment.
@@ -67,6 +101,11 @@ function assessHealth(device: Device, channels: DeviceChannel[]): DeviceHealth {
 		}
 	}
 
+	if (device.wifiStrength != null) {
+		const wifiIssue = assessWifiStrength(device.wifiStrength);
+		if (wifiIssue) issues.push(wifiIssue);
+	}
+
 	if (device.status !== "online") {
 		issues.push({
 			code: "offline",

packages/web/tests/device-health-badge.test.tsx

@@ -167,4 +167,17 @@ describe("DeviceHealthBadge", () => {
 
 		expect(screen.getByRole("tooltip")).toHaveTextContent("stale");
 	});
+
+	it("shows weak Wi-Fi signal in the tooltip", () => {
+		const device = makeDevice({ status: "online", battery: 80, wifiStrength: -78 });
+		const channels = [makeChannel()];
+
+		render(<DeviceHealthBadge device={device} channels={channels} />);
+
+		const badge = screen.getByLabelText("Device health: Warning");
+		fireEvent.mouseEnter(badge);
+
+		expect(screen.getByRole("tooltip")).toHaveTextContent("Wi-Fi signal weak");
+		expect(screen.getByRole("tooltip")).toHaveTextContent("RSSI -78 dBm");
+	});
 });