Phase one
T+0 → T+40 min
Find the damage
Damage has a signature, and it is a shape. Collagen I is a triple helix wound tight enough that its whole length offers a passing molecule exactly one purchase: the fragment end, which intact matrix keeps buried. Cut the tissue and those ends become the most common feature of the neighbourhood — eleven per micron along the severed line, against a background the assay reads as zero.
The carrier reads that density and does arithmetic with it. Below the threshold the complex passes and stays in circulation. Above it, the shell opens and the site is tagged. A full pass of the circulation takes forty minutes in a limb and under nine in a well-perfused organ, and the tag census — the count of live tags in a field — peaks at T+38 and holds flat for the remaining seventy-one hours.
A wound gets one address pass. Everything after this phase works from the list it produced, which is why the threshold is set where it is: a rebuild with no address lands on the first surface it meets, and the first surface it meets is healthy tissue.
Address pass — 11 ends/µm, tag census flat from T+38