Function ensureSession

src/tools/shared/spawnMultiAgent.ts:172–187

* Creates a new tmux session if it doesn't exist

(sessionName: string)

 * Creates a new tmux session if it doesn't exist
 */
async function ensureSession(sessionName: string): Promise<void> {
  const exists = await hasSession(sessionName)
  if (!exists) {
    const result = await execFileNoThrow(TMUX_COMMAND, [
      'new-session',
      '-d',
      '-s',
      sessionName,
    ])
    if (result.code !== 0) {
      throw new Error(
        `Failed to create tmux session '${sessionName}': ${result.stderr || 'Unknown error'}`,
      )
    }
  }
}

/**
 * Builds CLI flags to propagate from the current session to spawned teammates.