diff --git a/devolutions-gateway/src/api/tunnel.rs b/devolutions-gateway/src/api/tunnel.rs
index 6c3af7254..ffd7270d6 100644
--- a/devolutions-gateway/src/api/tunnel.rs
+++ b/devolutions-gateway/src/api/tunnel.rs
@@ -37,20 +37,37 @@ pub struct EnrollResponse {
 
 #[derive(Serialize)]
 pub struct AgentDomainAdvertisement {
+    /// Domain route advertised by the Agent.
     pub domain: String,
+    /// Whether the Agent discovered the domain automatically.
     pub auto_detected: bool,
 }
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum AgentStatus {
+    /// No tunnel connection exists for the Agent.
+    Offline,
+    /// The Agent has a tunnel connection and a recent heartbeat.
+    Online,
+    /// The Agent has a tunnel connection, but its heartbeat has expired.
+    Unresponsive,
+}
+
 #[derive(Serialize)]
 pub struct AgentInfo {
+    /// Stable Agent identity.
     pub agent_id: Uuid,
+    /// Unique management name assigned during enrollment.
     pub name: String,
-    pub cert_fingerprint: Option<String>,
-    pub is_online: bool,
+    /// Current tunnel connection status.
+    pub status: AgentStatus,
+    /// Last heartbeat timestamp in milliseconds since the Unix epoch.
     pub last_seen_ms: Option<u64>,
+    /// Subnet routes currently advertised by the Agent.
     pub subnets: Option<Vec<String>>,
+    /// Domain routes currently advertised by the Agent.
     pub domains: Option<Vec<AgentDomainAdvertisement>>,
-    pub route_epoch: Option<u64>,
 }
 
 pub fn make_router<S>(state: DgwState) -> Router<S> {
@@ -194,20 +211,21 @@ fn agent_info(
         return AgentInfo {
             agent_id: accepted.agent_id,
             name: accepted.name,
-            cert_fingerprint: None,
-            is_online: false,
+            status: AgentStatus::Offline,
             last_seen_ms: None,
             subnets: None,
             domains: None,
-            route_epoch: None,
         };
     };
 
     AgentInfo {
         agent_id: accepted.agent_id,
         name: accepted.name,
-        cert_fingerprint: Some(runtime.cert_fingerprint),
-        is_online: runtime.is_online,
+        status: if runtime.is_online {
+            AgentStatus::Online
+        } else {
+            AgentStatus::Unresponsive
+        },
         last_seen_ms: Some(runtime.last_seen_ms),
         subnets: Some(runtime.subnets),
         domains: Some(
@@ -220,7 +238,6 @@ fn agent_info(
                 })
                 .collect(),
         ),
-        route_epoch: Some(runtime.route_epoch),
     }
 }
 
@@ -292,3 +309,38 @@ async fn delete_agent(
 
     Ok(axum::http::StatusCode::NO_CONTENT)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn accepted_agent(agent_id: Uuid) -> agent_tunnel::authorization::AcceptedAgent {
+        agent_tunnel::authorization::AcceptedAgent {
+            agent_id,
+            name: String::from("montreal-office"),
+            client_spki_sha256: [0x11; 32],
+        }
+    }
+
+    #[test]
+    fn connected_agent_without_recent_heartbeat_is_unresponsive() {
+        let agent_id = Uuid::new_v4();
+        let runtime = agent_tunnel::registry::AgentInfo {
+            agent_id,
+            name: String::from("montreal-office"),
+            cert_fingerprint: String::from("fingerprint"),
+            is_online: false,
+            last_seen_ms: 1234,
+            subnets: Vec::new(),
+            domains: Vec::new(),
+            route_epoch: 1,
+        };
+
+        let info = agent_info(accepted_agent(agent_id), Some(runtime));
+
+        assert_eq!(info.status, AgentStatus::Unresponsive);
+        assert_eq!(info.last_seen_ms, Some(1234));
+        assert_eq!(info.subnets, Some(Vec::new()));
+        assert!(info.domains.is_some_and(|domains| domains.is_empty()));
+    }
+}
diff --git a/testsuite/tests/cli/agent/tunnel.rs b/testsuite/tests/cli/agent/tunnel.rs
index 55a5e1dae..d6460ae57 100644
--- a/testsuite/tests/cli/agent/tunnel.rs
+++ b/testsuite/tests/cli/agent/tunnel.rs
@@ -473,8 +473,7 @@ async fn wait_for_registered_agent(
                             })
                         });
 
-                if agent.get("is_online").and_then(serde_json::Value::as_bool) == Some(true)
-                    && agent.get("route_epoch").and_then(serde_json::Value::as_u64) == Some(1)
+                if agent.get("status").and_then(serde_json::Value::as_str) == Some("online")
                     && subnets == expected_subnets
                     && domains == expected_domains
                     && domains_are_explicit
@@ -680,14 +679,14 @@ async fn enrolled_agent_forwards_domain_only_route_and_reconnects() {
         Some("smoke-agent")
     );
     assert_eq!(
-        offline.get("is_online").and_then(serde_json::Value::as_bool),
-        Some(false)
+        offline.get("status").and_then(serde_json::Value::as_str),
+        Some("offline")
     );
-    assert!(offline.get("cert_fingerprint").is_some_and(serde_json::Value::is_null));
     assert!(offline.get("last_seen_ms").is_some_and(serde_json::Value::is_null));
     assert!(offline.get("subnets").is_some_and(serde_json::Value::is_null));
     assert!(offline.get("domains").is_some_and(serde_json::Value::is_null));
-    assert!(offline.get("route_epoch").is_some_and(serde_json::Value::is_null));
+    assert!(offline.get("cert_fingerprint").is_none());
+    assert!(offline.get("route_epoch").is_none());
     let mut agent = agent_tokio_cmd()
         .env("DAGENT_CONFIG_PATH", agent_config.path())
         .arg("run")