React Flow draws nothing for an edge whose handle ID resolves to no element, so
such an edge persists in the DB and is simply invisible on the canvas, with no
error anywhere. Nothing could reach that state while only the UI wrote handles;
exposing source_handle/target_handle over MCP opens it up, which is the same
failure the shrink remap already prevents from the other direction.
- POST /edges and PATCH /edges/{id} answer 422 when a caller-supplied handle
names a slot its node doesn't have — including a side it opted out of, since
left/right default to no connection point at all.
- Handles outside the per-side vocabulary ('cluster-right' and friends) belong
to their own renderer and are left alone.
- The auto-assignment corrects its own pick instead of raising: it always names
a top/bottom slot 0, which a node that zeroed those sides no longer draws.
A node with no connection point anywhere keeps the original.
- parse_side_handle in schemas/utils.py reads both the source form and the
'<side>-t' target twin the auto-assignment stores.
ha-relevant: no
Pouzor
08d85a40c1