Tone describes the way the author seems to feel about the subject of the text. The tone of this text seems somewhat indifferent, or emotionless. The narrator describes a pretty violent and terrifying event—a young boy loses his hand to a saw (an injury from which the boy later dies)—in an economical and even indifferent way:

At the word ["supper"], the saw,
As if to prove saws knew what supper meant,
Leaped out at the boy's hand, or seemed to leap—
He must have given the hand. However it was,
Neither refused the meeting.

Such a description, where the saw and the hand are personified as accepting a meeting with one another, makes the event seem almost civilized. The narrator does not express any horror at the event, though he "wish[es] they might have" given the boy the rest of the night off so that it could have been avoided. However, given the name of the poem, "Out, Out—"— an allusion to a line from Shakespeare's Macbeth—the tone also conveys a sense of the inevitability of tragedies like this, as they occur all the time. People die all the time. The original line is "Out, out, brief candle"; the "brief candle" is a metaphor for life—something that doesn't last very long and can go out, so to speak, so quickly and without warning: just as this young boy's life does. Frost adopts this emotionally detached tone as if to convey how commonplace deaths are, even tragic ones; this is why, in the end, everyone else, "since they / Were not the one dead, turned to their affairs." Life goes on.

And then—the watcher at his pulse took fright.

No one believed. They listened at his heart.

Little—less—nothing!—and that ended it. 

No more to build on there. And they, since they

Were not the one dead, turned to their affairs.

Frost is using a very unemotional and detached tone of voice in describing the tragic event recorded in "Out, Out." There is no personal involvement or connection between the voice telling the story and the persons actually involved in the action.

"Call it a day, I wish they might have said" indicates the narrator's awareness of how the events played out, but there is no indication of the narrator's approval or condemnation of the way in which the boy's responsibilities and capabilities were assessed and used or abused. The narrator expresses the wish that the boy had been spared the accident and the early death that resulted.

Once the accident happens, however, the narration is very matter-of-fact and straightforward. The boy pleads with his sister - "Don't let him cut my hand off" - but the injury is too severe. The boy dies. Life goes on - "they, since they were not the one dead, turned to their affairs."