Function applyGrouping

src/utils/groupToolUses.ts:54–182

(
  messages: MessageWithoutProgress[],
  tools: Tools,
  verbose: boolean = false,
)

 * When verbose is true, skips grouping so messages render at original positions.
 */
export function applyGrouping(
  messages: MessageWithoutProgress[],
  tools: Tools,
  verbose: boolean = false,
): GroupingResult {
  // In verbose mode, don't group - each message renders at its original position
  if (verbose) {
    return {
      messages: messages,
    }
  }
  const toolsWithGrouping = getToolsWithGrouping(tools)

  // First pass: group tool uses by message.id + tool name
  const groups = new Map<
    string,
    NormalizedAssistantMessage<BetaToolUseBlock>[]
  >()

  for (const msg of messages) {
    const info = getToolUseInfo(msg)
    if (info && toolsWithGrouping.has(info.toolName)) {
      const key = `${info.messageId}:${info.toolName}`
      const group = groups.get(key) ?? []
      group.push(msg as NormalizedAssistantMessage<BetaToolUseBlock>)
      groups.set(key, group)
    }
  }

  // Identify valid groups (2+ items) and collect their tool use IDs
  const validGroups = new Map<
    string,
    NormalizedAssistantMessage<BetaToolUseBlock>[]
  >()
  const groupedToolUseIds = new Set<string>()

  for (const [key, group] of groups) {
    if (group.length >= 2) {
      validGroups.set(key, group)
      for (const msg of group) {
        const info = getToolUseInfo(msg)
        if (info) {
          groupedToolUseIds.add(info.toolUseId)
        }
      }
    }
  }

  // Collect result messages for grouped tool_uses
  // Map from tool_use_id to the user message containing that result
  const resultsByToolUseId = new Map<string, NormalizedUserMessage>()

  for (const msg of messages) {
    if (msg.type === 'user') {
      for (const content of msg.message.content) {
        if (
          content.type === 'tool_result' &&
          groupedToolUseIds.has(content.tool_use_id)