Function isNavigableMessage

src/components/messageActions.tsx:18–64

(msg: NavigableMessage)

// Tier-2 blocklist (tier-1 is height > 0) — things that render but aren't actionable.
export function isNavigableMessage(msg: NavigableMessage): boolean {
  switch (msg.type) {
    case 'assistant':
      {
        const b = msg.message.content[0];
        // Text responses (minus AssistantTextMessage's return-null cases — tier-1
        // misses unmeasured virtual items), or tool calls with extractable input.
        return b?.type === 'text' && !isEmptyMessageText(b.text) && !SYNTHETIC_MESSAGES.has(b.text) || b?.type === 'tool_use' && b.name in PRIMARY_INPUT;
      }
    case 'user':
      {
        if (msg.isMeta || msg.isCompactSummary) return false;
        const b = msg.message.content[0];
        if (b?.type !== 'text') return false;
        // Interrupt etc. — synthetic, not user-authored.
        if (SYNTHETIC_MESSAGES.has(b.text)) return false;
        // Same filter as VirtualMessageList sticky-prompt: XML-wrapped (command
        // expansions, bash-stdout, etc.) aren't real prompts.
        return !stripSystemReminders(b.text).startsWith('<');
      }
    case 'system':
      // biome-ignore lint/nursery/useExhaustiveSwitchCases: blocklist — fallthrough return-true is the design
      switch (msg.subtype) {
        case 'api_metrics':
        case 'stop_hook_summary':
        case 'turn_duration':
        case 'memory_saved':
        case 'agents_killed':
        case 'away_summary':
        case 'thinking':
          return false;
      }
      return true;
    case 'grouped_tool_use':
    case 'collapsed_read_search':
      return true;
    case 'attachment':
      switch (msg.attachment.type) {
        case 'queued_command':
        case 'diagnostics':
        case 'hook_blocking_error':
        case 'hook_error_during_execution':
          return true;
      }
      return false;
  }
}
type PrimaryInput = {
  label: string;
  extract: (input: Record<string, unknown>) => string | undefined;