Function handleSpawnSplitPane

src/tools/shared/spawnMultiAgent.ts:305–539

* Handle spawn operation using split-pane view (default). * When inside tmux: Creates teammates in a shared window with leader on left, teammates on right. * When outside tmux: Creates a claude-swarm session with all teammates in a tiled layout.

(
  input: SpawnInput,
  context: ToolUseContext,
)

 * When outside tmux: Creates a claude-swarm session with all teammates in a tiled layout.
 */
async function handleSpawnSplitPane(
  input: SpawnInput,
  context: ToolUseContext,
): Promise<{ data: SpawnOutput }> {
  const { setAppState, getAppState } = context
  const { name, prompt, agent_type, cwd, plan_mode_required } = input

  // Resolve model: 'inherit' → leader's model; undefined → default Opus
  const model = resolveTeammateModel(input.model, getAppState().mainLoopModel)

  if (!name || !prompt) {
    throw new Error('name and prompt are required for spawn operation')
  }

  // Get team name from input or inherit from leader's team context
  const appState = getAppState()
  const teamName = input.team_name || appState.teamContext?.teamName

  if (!teamName) {
    throw new Error(
      'team_name is required for spawn operation. Either provide team_name in input or call spawnTeam first to establish team context.',
    )
  }

  // Generate unique name if duplicate exists in team
  const uniqueName = await generateUniqueTeammateName(name, teamName)

  // Sanitize the name to prevent @ in agent IDs (would break agentName@teamName format)
  const sanitizedName = sanitizeAgentName(uniqueName)

  // Generate deterministic agent ID from name and team
  const teammateId = formatAgentId(sanitizedName, teamName)
  const workingDir = cwd || getCwd()

  // Detect the appropriate backend and check if setup is needed
  let detectionResult = await detectAndGetBackend()

  // If in iTerm2 but it2 isn't set up, prompt the user
  if (detectionResult.needsIt2Setup && context.setToolJSX) {
    const tmuxAvailable = await isTmuxAvailable()

    // Show the setup prompt and wait for user decision
    const setupResult = await new Promise<
      'installed' | 'use-tmux' | 'cancelled'
    >(resolve => {
      context.setToolJSX!({
        jsx: React.createElement(It2SetupPrompt, {
          onDone: resolve,
          tmuxAvailable,
        }),
        shouldHidePromptInput: true,
      })
    })

    // Clear the JSX
    context.setToolJSX(null)

    if (setupResult === 'cancelled') {