My noir character would not realistically carry a bag around so instead I am going to describe what one could expect to find in his desk on a normal day.
Top of the desk can usually be expected to be covered in scattered newspapers. A typewriter sits next to a leather bound book in which Jack keeps his financial logs in. An ashtray sits on the right side of the desk next to the typewriter where Jack can easily ash his cigarette while he sits and sips his scotch. The room has no windows and only a dimly lit light that sits on the left corner of the table just next to the rotary phone. Inside the top drawer sits a loaded .38 snub nose revolver and some rarely used stationary and a pair of reading glasses. In the lower drawer, Jack keeps a bottle of scotch and a few dusty glasses in case he ever wants a drink and doesn’t want to break concentration long enough to walk downstairs.