diff --git a/backend/src/db/push_tokens.rs b/backend/src/db/push_tokens.rs
index 58d80c8..f2bed43 100644
--- a/backend/src/db/push_tokens.rs
+++ b/backend/src/db/push_tokens.rs
@@ -124,7 +124,11 @@ mod tests {
         let after_update = list().unwrap();
         let rows: Vec<_> = after_update.iter().filter(|t| t.token == token).collect();
         assert_eq!(rows.len(), 1, "Re-registering must not create a second row");
-        assert_eq!(rows[0].platform, PushPlatform::Ios, "Platform should update");
+        assert_eq!(
+            rows[0].platform,
+            PushPlatform::Ios,
+            "Platform should update"
+        );
         assert_eq!(
             rows[0].created_on, created_on,
             "created_on must be preserved across an upsert"
diff --git a/backend/src/main.rs b/backend/src/main.rs
index fb1adec..765edac 100644
--- a/backend/src/main.rs
+++ b/backend/src/main.rs
@@ -1,6 +1,7 @@
 use crate::settings::get_settings;
 use clap::Parser;
-use log::{LevelFilter, info};
+use log::{LevelFilter, error, info};
+use std::future::Future;
 
 mod data;
 mod db;
@@ -66,15 +67,31 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // Start the device scanners, web server, retention cleaner, and notification delivery loop in
     // parallel. Notification delivery runs on its own task so a slow Pushover never stalls a scan.
+    // Each task is wrapped so that if it exits with an error (e.g. the DHCP scanner failing to bind
+    // its socket because the port is already in use) the failure is logged rather than silently
+    // swallowed — otherwise a scanner just appears "off" with no explanation.
     tokio::join!(
-        scanners::arp::scanner::scan(),
-        scanners::mdns::scanner::listen(),
-        scanners::ssdp::scanner::listen(),
-        scanners::dhcp::scanner::listen(),
-        scanners::snmp::scanner::scan(),
-        web_server::serve(),
+        log_task_errors("ARP scanner", scanners::arp::scanner::scan()),
+        log_task_errors("mDNS scanner", scanners::mdns::scanner::listen()),
+        log_task_errors("SSDP scanner", scanners::ssdp::scanner::listen()),
+        log_task_errors("DHCP scanner", scanners::dhcp::scanner::listen()),
+        log_task_errors("SNMP scanner", scanners::snmp::scanner::scan()),
+        log_task_errors("web server", web_server::serve()),
         retention::run(),
-        notifications::run_delivery()
-    )
-    .0
+        notifications::run_delivery(),
+    );
+
+    Ok(())
+}
+
+/// Await a long-running task and log its error if it exits with one. Without this the errors of
+/// every task but the first were dropped by `tokio::join!`, so a scanner that failed to start
+/// (for example the DHCP scanner being unable to bind port 67) reported no diagnostic at all.
+async fn log_task_errors<F>(name: &str, task: F)
+where
+    F: Future<Output = Result<(), Box<dyn std::error::Error>>>,
+{
+    if let Err(err) = task.await {
+        error!("{name} exited with error: {err}");
+    }
 }
diff --git a/backend/src/model/push_tokens.rs b/backend/src/model/push_tokens.rs
index bc851ab..4dcc2f9 100644
--- a/backend/src/model/push_tokens.rs
+++ b/backend/src/model/push_tokens.rs
@@ -107,7 +107,10 @@ mod tests {
 
     #[test]
     fn platform_parse_is_case_insensitive() {
-        assert_eq!("ANDROID".parse::<PushPlatform>().unwrap(), PushPlatform::Android);
+        assert_eq!(
+            "ANDROID".parse::<PushPlatform>().unwrap(),
+            PushPlatform::Android
+        );
         assert_eq!("iOS".parse::<PushPlatform>().unwrap(), PushPlatform::Ios);
     }
 
diff --git a/backend/src/notifications/delivery.rs b/backend/src/notifications/delivery.rs
index 3c524e0..a6d5a4f 100644
--- a/backend/src/notifications/delivery.rs
+++ b/backend/src/notifications/delivery.rs
@@ -62,7 +62,11 @@ async fn deliver(request: DeliveryRequest) {
             // The relay URL defaults to the project-operated relay, so the [notifications.push]
             // section is optional. The send call is async (reqwest), so unlike Pushover it is
             // awaited directly rather than dispatched to the blocking pool.
-            let config = get_settings().notifications.push.clone().unwrap_or_default();
+            let config = get_settings()
+                .notifications
+                .push
+                .clone()
+                .unwrap_or_default();
             if let Err(err) = push::send(&config, request.title, request.body).await {
                 error!("Failed to deliver notification via the push relay: {err}");
             }
diff --git a/backend/src/notifications/push.rs b/backend/src/notifications/push.rs
index 6c5871c..9a82037 100644
--- a/backend/src/notifications/push.rs
+++ b/backend/src/notifications/push.rs
@@ -77,7 +77,10 @@ pub async fn send(config: &Push, title: String, body: String) -> Result<usize, D
     let parsed: RelayResponse = response.json().await?;
     let dead = dead_tokens(&parsed.results);
     if !dead.is_empty() {
-        debug!("Pruning {} dead push token(s) reported by the relay", dead.len());
+        debug!(
+            "Pruning {} dead push token(s) reported by the relay",
+            dead.len()
+        );
         db::run_blocking(move || db::push_tokens::delete_many(&dead)).await?;
     }
 
@@ -150,7 +153,10 @@ mod tests {
             relay_url: format!("http://{addr}/v1/push"),
         };
         let delivered = send(&config, "title".into(), "body".into()).await.unwrap();
-        assert_eq!(delivered, 1, "Only the live token should count as delivered");
+        assert_eq!(
+            delivered, 1,
+            "Only the live token should count as delivered"
+        );
 
         let all = db::push_tokens::list().unwrap();
         assert!(
diff --git a/backend/src/web_server.rs b/backend/src/web_server.rs
index b8f6c46..a65d19c 100644
--- a/backend/src/web_server.rs
+++ b/backend/src/web_server.rs
@@ -335,4 +335,37 @@ mod tests {
         let openapi = <ApiDoc as OpenApi>::openapi();
         assert_eq!(openapi.info.version, env!("CARGO_PKG_VERSION"));
     }
+
+    #[test]
+    fn openapi_operation_ids_are_unique() {
+        // Every operation defaults its operationId to its handler function name, so handlers that
+        // share a name (e.g. each scanner's `status`, or `read`/`list` across resources) collide.
+        // Duplicate operationIds are invalid OpenAPI and make Swagger UI's "Try it out" execute the
+        // first operation with that id (so the DHCP doc hit `/api/arp_scanner/status`). Assert they
+        // are all unique so that regression cannot return.
+        let openapi = <ApiDoc as OpenApi>::openapi();
+        let mut seen = std::collections::HashSet::new();
+        for (path, item) in &openapi.paths.paths {
+            let operations = [
+                &item.get,
+                &item.put,
+                &item.post,
+                &item.delete,
+                &item.options,
+                &item.head,
+                &item.patch,
+                &item.trace,
+            ];
+            for operation in operations.into_iter().flatten() {
+                let id = operation
+                    .operation_id
+                    .as_ref()
+                    .unwrap_or_else(|| panic!("{path} has an operation with no operationId"));
+                assert!(
+                    seen.insert(id.clone()),
+                    "duplicate operationId {id:?} (at {path})"
+                );
+            }
+        }
+    }
 }
diff --git a/backend/src/web_server/arp_scanner.rs b/backend/src/web_server/arp_scanner.rs
index c68e68f..06d56c8 100644
--- a/backend/src/web_server/arp_scanner.rs
+++ b/backend/src/web_server/arp_scanner.rs
@@ -5,6 +5,7 @@ use crate::web_server::scanner_status::{ActiveScannerStatusResponse, active_resp
 #[utoipa::path(
     get,
     path = "/api/arp_scanner/status",
+    operation_id = "arp_scanner_status",
     tag = "arp_scanner",
     responses(
         (status = 200, description = "ARP scanner status", body = ActiveScannerStatusResponse),
diff --git a/backend/src/web_server/config.rs b/backend/src/web_server/config.rs
index 8cb0711..2dc5425 100644
--- a/backend/src/web_server/config.rs
+++ b/backend/src/web_server/config.rs
@@ -6,6 +6,7 @@ use crate::settings::get_settings;
 #[utoipa::path(
     get,
     path = "/api/config",
+    operation_id = "config_read",
     tag = "config",
     responses(
         (status = 200, description = "Front-end configuration", body = Config),
diff --git a/backend/src/web_server/device_events.rs b/backend/src/web_server/device_events.rs
index 8b5a4a0..71e4cfe 100644
--- a/backend/src/web_server/device_events.rs
+++ b/backend/src/web_server/device_events.rs
@@ -12,6 +12,7 @@ use crate::{db, model::device_events::DeviceEvent, web_server::utils};
 #[utoipa::path(
     get,
     path = "/api/devices/{mac_address}/events",
+    operation_id = "device_events_list",
     tag = "device_events",
     params(
         ("mac_address" = String, Path, description = "MAC address of the device"),
diff --git a/backend/src/web_server/devices.rs b/backend/src/web_server/devices.rs
index edc527a..dedfbd9 100644
--- a/backend/src/web_server/devices.rs
+++ b/backend/src/web_server/devices.rs
@@ -18,6 +18,7 @@ use crate::web_server::utils;
 #[utoipa::path(
     get,
     path = "/api/devices",
+    operation_id = "devices_list",
     tag = "devices",
     params(
         ("is_registered" = Option<bool>, Query, description = "Filter by registration status"),
@@ -95,6 +96,7 @@ pub async fn list(
 #[utoipa::path(
     get,
     path = "/api/devices/{mac_address}",
+    operation_id = "devices_read",
     tag = "devices",
     params(
         ("mac_address" = String, Path, description = "MAC address of the device"),
@@ -116,6 +118,7 @@ pub async fn read(Path(mac_address): Path<String>) -> Result<Json<Device>, Statu
 #[utoipa::path(
     put,
     path = "/api/devices",
+    operation_id = "devices_register",
     tag = "devices",
     request_body = RegisterDevicePayload,
     responses(
@@ -235,6 +238,7 @@ pub async fn update(
 #[utoipa::path(
     delete,
     path = "/api/devices/{mac_address}",
+    operation_id = "devices_unregister",
     tag = "devices",
     params(
         ("mac_address" = String, Path, description = "MAC address of the device"),
diff --git a/backend/src/web_server/dhcp_scanner.rs b/backend/src/web_server/dhcp_scanner.rs
index 7be317a..35de1e5 100644
--- a/backend/src/web_server/dhcp_scanner.rs
+++ b/backend/src/web_server/dhcp_scanner.rs
@@ -5,6 +5,7 @@ use crate::web_server::scanner_status::{PassiveScannerStatusResponse, passive_re
 #[utoipa::path(
     get,
     path = "/api/dhcp_scanner/status",
+    operation_id = "dhcp_scanner_status",
     tag = "dhcp_scanner",
     responses(
         (status = 200, description = "DHCP scanner status", body = PassiveScannerStatusResponse),
diff --git a/backend/src/web_server/mdns_scanner.rs b/backend/src/web_server/mdns_scanner.rs
index da5c27e..cd0ec32 100644
--- a/backend/src/web_server/mdns_scanner.rs
+++ b/backend/src/web_server/mdns_scanner.rs
@@ -5,6 +5,7 @@ use crate::web_server::scanner_status::{PassiveScannerStatusResponse, passive_re
 #[utoipa::path(
     get,
     path = "/api/mdns_scanner/status",
+    operation_id = "mdns_scanner_status",
     tag = "mdns_scanner",
     responses(
         (status = 200, description = "mDNS scanner status", body = PassiveScannerStatusResponse),
diff --git a/backend/src/web_server/notifications.rs b/backend/src/web_server/notifications.rs
index 33e706f..ddb6582 100644
--- a/backend/src/web_server/notifications.rs
+++ b/backend/src/web_server/notifications.rs
@@ -26,6 +26,7 @@ pub struct TestNotificationResponse {
 #[utoipa::path(
     get,
     path = "/api/notifications/{id}",
+    operation_id = "notifications_read",
     tag = "notifications",
     params(
         ("id" = i64, Path, description = "Notification ID"),
@@ -150,6 +151,7 @@ pub async fn send_test() -> Result<Json<TestNotificationResponse>, StatusCode> {
 #[utoipa::path(
     get,
     path = "/api/notifications",
+    operation_id = "notifications_list",
     tag = "notifications",
     params(
         ("is_new" = Option<bool>, Query, description = "Filter by new/read status"),
diff --git a/backend/src/web_server/push_tokens.rs b/backend/src/web_server/push_tokens.rs
index 63ab72a..9e98448 100644
--- a/backend/src/web_server/push_tokens.rs
+++ b/backend/src/web_server/push_tokens.rs
@@ -11,6 +11,7 @@ use crate::model::push_tokens::PushPlatform;
 #[utoipa::path(
     put,
     path = "/api/push_tokens",
+    operation_id = "push_tokens_register",
     tag = "push_tokens",
     request_body = RegisterPushTokenPayload,
     responses(
@@ -38,6 +39,7 @@ pub async fn register(Json(payload): Json<RegisterPushTokenPayload>) -> impl Int
 #[utoipa::path(
     delete,
     path = "/api/push_tokens/{token}",
+    operation_id = "push_tokens_unregister",
     tag = "push_tokens",
     params(
         ("token" = String, Path, description = "The push token to unregister"),
diff --git a/backend/src/web_server/snmp_scanner.rs b/backend/src/web_server/snmp_scanner.rs
index 50e8c78..18e98ff 100644
--- a/backend/src/web_server/snmp_scanner.rs
+++ b/backend/src/web_server/snmp_scanner.rs
@@ -5,6 +5,7 @@ use crate::web_server::scanner_status::{ActiveScannerStatusResponse, active_resp
 #[utoipa::path(
     get,
     path = "/api/snmp_scanner/status",
+    operation_id = "snmp_scanner_status",
     tag = "snmp_scanner",
     responses(
         (status = 200, description = "SNMP scanner status", body = ActiveScannerStatusResponse),
diff --git a/backend/src/web_server/ssdp_scanner.rs b/backend/src/web_server/ssdp_scanner.rs
index cdf413c..8a910d7 100644
--- a/backend/src/web_server/ssdp_scanner.rs
+++ b/backend/src/web_server/ssdp_scanner.rs
@@ -5,6 +5,7 @@ use crate::web_server::scanner_status::{PassiveScannerStatusResponse, passive_re
 #[utoipa::path(
     get,
     path = "/api/ssdp_scanner/status",
+    operation_id = "ssdp_scanner_status",
     tag = "ssdp_scanner",
     responses(
         (status = 200, description = "SSDP scanner status", body = PassiveScannerStatusResponse),