Changeset

Author: julenmendieta

.changeset/vhh-presence-driven-chain-menu.md

@@ -0,0 +1,12 @@
+---
+"@platforma-open/milaboratories.vj-usage.model": patch
+"@platforma-open/milaboratories.vj-usage.ui": patch
+"@platforma-open/milaboratories.vj-usage": patch
+---
+
+Only offer single-cell chains that actually have columns. The chain selector was
+built from the receptor type alone, so on heavy-chain-only (VHH) single-cell input
+it still offered "Light" — picking it failed the workflow with `expected exactly 1
+V gene column for chain, got 0`. A new `availableScChains` model output reports the
+chains present for the selected dataset; the selector now lists only those (and is
+hidden when a single chain leaves nothing to choose).