fix: permission request ID mismatch, SSE duplicates, and subprocess cleanup (#137)

apps/backend/internal/agentctl/server/process/manager.go

@@ -711,8 +711,14 @@ func (m *Manager) GetProcessInfo() map[string]interface{} {
 // handlePermissionRequest handles permission requests from the agent
 // It stores the pending request and waits for a response from the backend
 func (m *Manager) handlePermissionRequest(ctx context.Context, req *adapter.PermissionRequest) (*adapter.PermissionResponse, error) {
-	// Generate a unique ID for this permission request
-	pendingID := fmt.Sprintf("%s-%s-%d", req.SessionID, req.ToolCallID, time.Now().UnixNano())
+	// Use the adapter-provided pending ID if available, otherwise generate one.
+	// This ensures the ID sent to the frontend matches the one used for response lookup.
+	// For OpenCode (per_xxx) and Claude Code (requestID), the adapter passes its ID
+	// so we use the same ID throughout the permission flow.
+	pendingID := req.PendingID
+	if pendingID == "" {
+		pendingID = fmt.Sprintf("%s-%s-%d", req.SessionID, req.ToolCallID, time.Now().UnixNano())
+	}
 
 	m.logger.Info("handling permission request",
 		zap.String("pending_id", pendingID),
@@ -747,7 +753,6 @@ func (m *Manager) handlePermissionRequest(ctx context.Context, req *adapter.Perm
 	}()
 
 	// Send notification to backend via updates channel
-	// We use a custom notification type that the backend will recognize
 	m.sendPermissionNotification(pending)
 
 	// Wait for response indefinitely - user may close and reopen the page
@@ -761,6 +766,8 @@ func (m *Manager) handlePermissionRequest(ctx context.Context, req *adapter.Perm
 	case <-ctx.Done():
 		m.logger.Warn("permission request context cancelled",
 			zap.String("pending_id", pendingID))
+		// Send cancellation notification so the backend can update the permission message status
+		m.sendPermissionCancelledNotification(pending)
 		return &adapter.PermissionResponse{Cancelled: true}, nil
 	}
 }
@@ -831,6 +838,29 @@ func (m *Manager) sendPermissionNotification(pending *PendingPermission) {
 	}
 }
 
+// sendPermissionCancelledNotification sends a notification that a permission request was cancelled.
+// This happens when the context is cancelled (e.g., agent completes or user stops the task)
+// before the user responds to the permission request.
+func (m *Manager) sendPermissionCancelledNotification(pending *PendingPermission) {
+	event := adapter.AgentEvent{
+		Type:      adapter.EventTypePermissionCancelled,
+		SessionID: pending.Request.SessionID,
+		PendingID: pending.ID,
+	}
+
+	m.logger.Info("sending permission cancelled notification",
+		zap.String("pending_id", pending.ID),
+		zap.String("session_id", pending.Request.SessionID))
+
+	select {
+	case m.updatesCh <- event:
+		// Sent successfully
+	default:
+		m.logger.Warn("updates channel full, dropping permission cancelled notification",
+			zap.String("pending_id", pending.ID))
+	}
+}
+
 // RespondToPermission responds to a pending permission request
 func (m *Manager) RespondToPermission(pendingID string, optionID string, cancelled bool) error {
 	m.permissionMu.RLock()

apps/backend/internal/agentctl/server/process/procattr_linux.go

@@ -0,0 +1,27 @@
+//go:build linux
+
+package process
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+// setProcGroup configures the command to run in its own process group.
+// This allows us to kill all child processes together.
+// On Linux, we also set Pdeathsig to ensure the child is killed if the parent dies
+// unexpectedly (SIGKILL, crash, etc.) without calling Stop().
+func setProcGroup(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid:   true,
+		Pdeathsig: syscall.SIGTERM,
+	}
+}
+
+// killProcessGroup kills the entire process group for the given PID.
+// Returns nil if successful, or an error if the kill failed.
+func killProcessGroup(pid int) error {
+	// Kill the entire process group by using negative PID
+	return syscall.Kill(-pid, syscall.SIGKILL)
+}
+

apps/backend/internal/agentctl/server/process/procattr_unix.go

@@ -1,4 +1,4 @@
-//go:build unix
+//go:build unix && !linux
 
 package process
 
@@ -9,6 +9,8 @@ import (
 
 // setProcGroup configures the command to run in its own process group.
 // This allows us to kill all child processes together.
+// Note: Pdeathsig is Linux-specific and not available on macOS/BSD.
+// On these platforms, orphan cleanup relies on explicit Stop() calls.
 func setProcGroup(cmd *exec.Cmd) {
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 }