Reuse Membrane. Customize the rough edges.

Use Membrane’s React controls inside the Halosight workspace. Restyle the standard controls and own the small parts where the interaction needs to change.

Part	Recommendation
Field & value picker	Reuse ComboBox. Feed it searchable field names and API names; keep it anchored to the value being edited.
Standard formulas	Reuse DataInput where its interaction fits. Preserve schema-aware fields, nested values, and formulas.
Appearance	Apply Halosight typography, spacing, borders, and focus states through the SDK’s CSS styling hooks.
If / Then / Otherwise	Use a small custom layout with inline conditions, a visible AND/OR switch, and nested outputs. Keep Membrane’s native expression format.
Workspace	Keep Halosight’s Import / Export / Both views, AI suggestions, custom fields, preview, and final Review / Apply.

Interaction rules

Edits are kept locally as you go. Collapse with a chevron or Escape; no Done button.
Keep the condition visible while changing its field, operator, or value.
Expand nested text or formulas directly under Then or Otherwise.
Search by field name or API name. Selecting a result closes the picker, not the editor.
Review and apply everything together. Closing an editor never applies configuration.

Implementation findings and limits

The published React package 0.29.2 exposes DataInput, ComboBox, and FilterInput. Its formula-component replacement provider is internal, so a full conditional-layout override is not a supported public hook.
FilterInput’s condition renderer explicitly handles AND, but has no explicit OR editing branch. A custom AND/OR layout is the better fit.
Membrane formulas already support conditional branches, AND/OR, text composition, and JSONata. Preserve existing expressions, including ones our GUI does not edit.
The checkout uses JavaScript SDK 0.15.4; the reviewed React package depends on 0.29.2. Test compatibility before upgrading. Its SWR dependency also needs to fit the app’s component and data-access boundaries.
The search issue still needs reproduction. Test focus, keyboard selection, stale async results, and popover stacking. FloatingPortalBoundary addresses controls inside custom dialogs.

Checked October 28, 2026 against official documentation and the published package. Detailed notes.

The v4 prototype uses synthetic data. It demonstrates the interaction; it does not embed the SDK or save to a CRM.