A method and a lateral entry guide tool for deploying a work string in a wellbore defining a window and a lateral wellbore extending from the window are described. The work string and the tool are run through the wellbore to a distance above the window. A locator subassembly is activated to detect the window. The tool is run through the wellbore in a downhole direction from the distance above the window past the window. After the locator subassembly indicates that the tool is past the window, a window entry depth is determined based a depth at which the window was detected. The work string is pulled back to position the tool at the window entry depth. A positioning subassembly is activated. The work string is run through the window while adjusting and calibrating the positioning subassembly as the work string pass through the window into the lateral wellbore.