Tone is defined as the attitude of the author about a subject, as seen in the perspective and language used to explore that subject in the writing. In the poem "Mother to Son", Langston Hughes explores the subjects of life and resiliency. To that degree, the tone can be considered resilient or gritty.
Its had tacks in it, and splinters, and boards torn up. And places with no carpet on the floors, bare. But all the time, i'se been climbing on, and reachin landins and turnin corners, and sometimes, doing in the dark where there ain't been no light.
In the above text, the mother is using the extended metaphor to explain her ability to bounce back after trials, and she uses her hardships to motivate and inspire her son to continue fighting. This mother's drive and determination, even after challenges have mounted, displays her resilience and grit.
Another possible tone of this poem is didactic. Didactic literature is defined as informational or instructional, usually explaining a truth or moral. While the definition implies a boring connotation, this is not always the case for didacticism. In fact, and is the case in, Mother to Son, the urgency of this mother's truth, keeps the poem from ever being described as boring.
...so boy, don't you sat down on them steps, cause you finds its kinda hard. Don't you fall now, for i'se still climbin on, and life for me ain't been no crystal stair.