Mac: surface gateway errors in remote test

apps/macos/Sources/Clawdis/ControlChannel.swift

@@ -99,8 +99,9 @@ final class ControlChannel: ObservableObject {
             self.state = .connected
             return payload
         } catch {
-            self.state = .degraded(error.localizedDescription)
-            throw error
+            let message = self.friendlyGatewayMessage(error)
+            self.state = .degraded(message)
+            throw ControlChannelError.badResponse(message)
         }
     }
 
@@ -116,11 +117,41 @@ final class ControlChannel: ObservableObject {
             self.state = .connected
             return data
         } catch {
-            self.state = .degraded(error.localizedDescription)
-            throw error
+            let message = self.friendlyGatewayMessage(error)
+            self.state = .degraded(message)
+            throw ControlChannelError.badResponse(message)
         }
     }
 
+    private func friendlyGatewayMessage(_ error: Error) -> String {
+        // Map URLSession/WS errors into user-facing, actionable text.
+        if let ctrlErr = error as? ControlChannelError, let desc = ctrlErr.errorDescription {
+            return desc
+        }
+
+        if let urlError = error as? URLError {
+            let port = RelayEnvironment.gatewayPort()
+            switch urlError.code {
+            case .cancelled:
+                return "Gateway connection was closed; start the relay (localhost:\(port)) and retry."
+            case .cannotFindHost, .cannotConnectToHost:
+                return "Cannot reach gateway at localhost:\(port); ensure the relay is running."
+            case .networkConnectionLost:
+                return "Gateway connection dropped; relay likely restarted—retry."
+            case .timedOut:
+                return "Gateway request timed out; check relay on localhost:\(port)."
+            case .notConnectedToInternet:
+                return "No network connectivity; cannot reach gateway."
+            default:
+                break
+            }
+        }
+
+        let nsError = error as NSError
+        let detail = nsError.localizedDescription.isEmpty ? "unknown gateway error" : nsError.localizedDescription
+        return "Gateway error: \(detail)"
+    }
+
     func sendSystemEvent(_ text: String) async throws {
         _ = try await self.request(method: "system-event", params: ["text": AnyHashable(text)])
     }

apps/macos/Sources/Clawdis/GatewayChannel.swift

@@ -41,7 +41,12 @@ private actor GatewayChannelActor {
         self.task?.cancel(with: .goingAway, reason: nil)
         self.task = self.session.webSocketTask(with: self.url)
         self.task?.resume()
-        try await self.sendHello()
+        do {
+            try await self.sendHello()
+        } catch {
+            let wrapped = self.wrap(error, context: "connect to gateway @ \(self.url.absoluteString)")
+            throw wrapped
+        }
         self.listen()
         self.connected = true
         self.backoffMs = 500
@@ -110,7 +115,8 @@ private actor GatewayChannelActor {
     }
 
     private func handleReceiveFailure(_ err: Error) async {
-        self.logger.error("gateway ws receive failed \(err.localizedDescription, privacy: .public)")
+        let wrapped = self.wrap(err, context: "gateway receive")
+        self.logger.error("gateway ws receive failed \(wrapped.localizedDescription, privacy: .public)")
         self.connected = false
         await self.scheduleReconnect()
     }
@@ -177,13 +183,18 @@ private actor GatewayChannelActor {
         do {
             try await self.connect()
         } catch {
-            self.logger.error("gateway reconnect failed \(error.localizedDescription, privacy: .public)")
+            let wrapped = self.wrap(error, context: "gateway reconnect")
+            self.logger.error("gateway reconnect failed \(wrapped.localizedDescription, privacy: .public)")
             await self.scheduleReconnect()
         }
     }
 
     func request(method: String, params: [String: AnyCodable]?) async throws -> Data {
-        try await self.connect()
+        do {
+            try await self.connect()
+        } catch {
+            throw self.wrap(error, context: "gateway connect")
+        }
         let id = UUID().uuidString
         let paramsObject = params?.reduce(into: [String: Any]()) { dict, entry in
             dict[entry.key] = entry.value.value
@@ -202,7 +213,7 @@ private actor GatewayChannelActor {
                     try await self.task?.send(.data(data))
                 } catch {
                     self.pending.removeValue(forKey: id)
-                    cont.resume(throwing: error)
+                    cont.resume(throwing: self.wrap(error, context: "gateway send \(method)"))
                 }
             }
         }
@@ -221,6 +232,20 @@ private actor GatewayChannelActor {
         }
         return Data()
     }
+
+    // Wrap low-level URLSession/WebSocket errors with context so UI can surface them.
+    private func wrap(_ error: Error, context: String) -> Error {
+        if let urlError = error as? URLError {
+            let desc = urlError.localizedDescription.isEmpty ? "cancelled" : urlError.localizedDescription
+            return NSError(
+                domain: urlError.errorDomain,
+                code: urlError.errorCode,
+                userInfo: [NSLocalizedDescriptionKey: "\(context): \(desc)"])
+        }
+        let ns = error as NSError
+        let desc = ns.localizedDescription.isEmpty ? "unknown" : ns.localizedDescription
+        return NSError(domain: ns.domain, code: ns.code, userInfo: [NSLocalizedDescriptionKey: "\(context): \(desc)"])
+    }
 }
 
 actor GatewayChannel {