References that answer the question you actually searched.

What is keypoint annotation?

What keypoints, skeletons and visibility flags are, how they differ from boxes and masks, then the workflow: schema, placing points, occlusion and left/right, review, export.

How to annotate keypoints in DataTorch

Step by step: put the keypoint schema and skeleton on a label, place points in order with the Keypoints tool, mark occluded points, edit with the Move tool, export to COCO.

The COCO keypoint format

All 17 keypoints in order, 0-based vs 1-based indexing, the official skeleton pairs, visibility flags, and worked annotation JSON.

Keypoint and pose estimation datasets

Downloadable keypoint datasets hosted on DataTorch, plus the standard benchmarks (COCO, MPII, CrowdPose, AP-10K and more) with sizes and keypoint counts.

The DSB2018 nuclei segmentation dataset

What is inside the standard nuclei benchmark, the per-nucleus mask format, common pitfalls, and which model to train: U-Net, StarDist, Cellpose, or Mask R-CNN.