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name: model-architecture description: "Inspect and modify YOLOv3 model YAMLs, anchors, Detect heads, parse_model behavior, strides, and tensor shapes." disable-model-invocation: true metadata: disco-role: operating license: AGPL 3.0

Model Architecture Sub-skill

Read this for models/yolo.py, models/common.py, model YAMLs, anchors, class counts, Detect, Model, DetectionModel, parse_model, stride/grid behavior, and output-shape debugging.

Use

• Read references/architecture.md for YAML structure, supported model files, and parser/head behavior.
• Use scripts/yolov3_model_yaml_probe.py to instantiate a YAML and report prediction shapes on a zero tensor.
• Read references/troubleshooting.md for class/anchor/channel mismatch issues.

Important facts

• Built-in detection YAMLs are models/yolov3.yaml, models/yolov3-spp.yaml, and models/yolov3-tiny.yaml.
• This repo does not contain segmentation, classification, pose, or newer YOLO task heads.
• Default Detect output has no = nc + 5; for COCO, 85 channels per anchor prediction.
• At 64x64, default YOLOv3-tiny produces (1, 60, 85) predictions.