Tideline by Elizabeth Bear

Tideline by Elizabeth Bear (Asimov’s SF, June 2007) opens with Chalcedony, a damaged combat vehicle, prospecting for “trash jewels” as it works its way along the beach in what eventually turns out to be a devastated future world. Then it meets a feral child called Belvedere. Belvedere asks the robot what it is doing, and Chalcedony tells him that it is gathering “shipwreck beads” to make necklaces. We later find out that it intends making 41 necklaces, one to commemorate each of the members of its combat unit, all of whom are now dead.
A relationship develops between the two, beginning with Belvedere picking up a chain with a Buddha figure on it and passing it up to the robot—Chalcedony has a damaged leg, which makes it difficult to stoop to ground level—and it reciprocates by microwaving a bag full of seashells and seaweed for the child. Chalcedony tells Belvedere to eat the seaweed too (“rich in nutrients”), the first instance of the robot mentoring and caring for the child over the following days and months (and which includes, at one point, the robot saving his life by killing two men who attack him). During this period Chalcedony also tells Belvedere stories about the members of its platoon.
Over the course of the story Chalcedony’s batteries run down—the solar charge it gets each day isn’t enough to keep it at full power—and it is also stuck between the cliff and the sea. The robot realises that it will not survive the approaching winter, so it works as quickly as it can on finishing its memorial necklaces before then.
The final part of the story (spoiler) sees the robot use some of the last of its precious energy reserves to save the life of an injured German Shepard found by Belvedere:

When the sun was up and the young dog was breathing comfortably, the gash along its haunch sewn closed and its bloodstream saturated with antibiotics, she turned back to the last necklace. She would have to work quickly, and Sergeant Patterson’s necklace contained the most fragile and beautiful beads, the ones Chalcedony had been most concerned with breaking and so had saved for last, when she would be most experienced.
Her motions grew slower as the day wore on, more laborious. The sun could not feed her enough to replace the expenditures of the night before. But bead linked into bead, and the necklace grew—bits of pewter, of pottery, of glass and mother of pearl. And the chalcedony Buddha, because Sergeant Patterson had been Chalcedony’s operator.

When Chalcedony wakes the next day after being recharged by the sun, the robot sees that Belvedere has finished assembling the necklace; Belvedere hands it over so Chalcedony can finish the job by hardening the links. Chalcedony then tasks Belvedere to go on an errantry, to find people to learn the platoon members’ stories and to wear the necklaces that commemorate them. When Belvedere asks what sort of people he should give them to, Chalcedony replies:

“People who would help a child,” she said. “Or a wounded dog. People like a platoon should be.”

This is a slow burn piece that is effectively done, but the degree of anthropomorphism in the story is both (a) its weak point (do we really believe a sentient war machine is a “she”, or would be grieving its comrades and making necklaces to remember them?¹) and (b) its strength (this kind of sentimentality goes down big with SF readers in general and awards voters in particular²).
***+ (Good to Very Good). 4,400 words. Story link.

1. The more you consider the way Chalcedony behaves, the less likely it all seems.

2. This story won the 2008 Hugo, Sturgeon, and Asimov’s Reader’s Poll Awards. Of course.