Oke, longer timeout values.

private/player.rkt

@@ -204,7 +204,9 @@
                         id action (length (playback-agent-commands agent)))
        command))))
 
-(define agent-heartbeat-timeout-seconds 10)
+;; Allow mobile network interruptions without discarding the playback session
+;; and pending commands while the agent continues playing cached audio.
+(define agent-heartbeat-timeout-seconds 120)
 
 (define (prune-stale-agents! value)
   (with-state-lock
@@ -1834,6 +1836,46 @@
            rackunit
            racket/file)
 
+  (test-case "agent survives a mobile interruption and expires after prolonged silence"
+    (let* ((app-id (make-string 64 #\c))
+           (value (make-player '() #:playlist-keystore #f #:local-output? #f
+                               #:allowed-agent-ids (list app-id))))
+      (dynamic-wind
+        void
+        (λ ()
+          (player-agent-register! value (hasheq 'appId app-id))
+          (let* ((agent (agent-by-id value app-id))
+                 (session (playback-session-for! value "anonymous"))
+                 (id (agent-renderer-id app-id))
+                 (command (enqueue-agent-command! value agent "pause")))
+            (set-playback-session-selected-id! session id)
+            (set-playback-session-backend! session agent)
+            (set-playback-session-backend-kind! session 'agent)
+            (set-playback-session-state! session 'playing)
+            (hash-set! (player-renderer-owners value) id session)
+            ;; A minute without polls must preserve the renderer and its owner.
+            (set-playback-agent-last-seen! agent (- (current-seconds) 60))
+            (prune-stale-agents! value)
+            (check-eq? (agent-by-id value app-id) agent)
+            (check-equal? (playback-session-selected-id session) id)
+            (check-eq? (playback-session-backend session) agent)
+            (check-eq? (playback-session-state session) 'playing)
+            (check-eq? (hash-ref (player-renderer-owners value) id #f) session)
+            ;; Reconnection delivers the pending command and refreshes liveness.
+            (check-equal? (hash-ref (player-agent-poll! value (hasheq 'appId app-id))
+                                    'command)
+                          command)
+            (prune-stale-agents! value)
+            (check-eq? (agent-by-id value app-id) agent)
+            (set-playback-agent-last-seen! agent (- (current-seconds) 121))
+            (prune-stale-agents! value)
+            (check-false (agent-by-id value app-id))
+            (check-false (renderer-by-id value id))
+            (check-false (playback-session-backend session))
+            (check-eq? (playback-session-state session) 'stopped)
+            (check-false (hash-ref (player-renderer-owners value) id #f))))
+        (λ () (player-close! value)))))
+
   (test-case "playlist versions cache 1000 tracks and follow user mutations"
     (let ((value (make-player '() #:playlist-keystore #f #:local-output? #f)))
       (dynamic-wind

scribblings/rkt-web-player.scrbl

@@ -124,6 +124,12 @@ renderers. The server can prefetch the next track to an agent for gapless
 transitions. A 256-bit application ID identifies the agent; the server's
 @tt{[playback-agents]} allowlist decides which agents may connect.
 
+The server keeps an agent's playback session and pending commands for up to
+two minutes without a status update, allowing brief mobile network outages.
+Polling within that period refreshes the connection; after longer silence,
+the server removes the agent from the available outputs. Already downloaded
+audio can continue playing on the agent during an interruption.
+
 Both agents retain downloaded tracks in a local disk cache with a budget of
 1 GB (1,000,000,000 bytes), evicting the least recently used tracks first.
 Selecting a cached track reuses its local file when the server address, source