gistfile1.el

(defvar my-helm-source-do-ag
  `((name . "the silver searcher")
    (candidates-process . helm-ag--do-ag-candidate-process)
    (persistent-action . helm-ag-persistent-action)
    (action . (("Open File" . helm-ag--action-find-file)
               ("Open File Other Window" . helm-ag--action--find-file-other-window)))
    (no-matchplugin)
    (nohighlight)
    (requires-pattern . 2)
    (candidate-number-limit . 200)))

(defun my-helm-mini ()
  (interactive)
  (require 'helm-files)
  (let ((helm-ff-transformer-show-only-basename nil)
        (sources '(helm-source-recentf
                   helm-source-buffers-list)))
      (let ((helm-ag-default-directory (or
                                        (with-project-root (cdr project-details))
                                        default-directory)))
        (with-library 'helm-ag (add-to-list 'sources 'my-helm-source-do-ag))
        (with-library 'helm-git-files (add-to-list 'sources 'helm-git-files:all-source))
        (helm-other-buffer sources "*helm mini*"))))

(with-library 'helm
  (require 'helm-config)

  (global-set-key (kbd "C-c a") 'my-helm-mini))