Explain R6 data authoring and record verification gaps

README.md

@@ -53,6 +53,8 @@ The example opens in an architecture view with work nested inside its performers
 
 **Model explorer** groups roots by engineering purpose and opens one container's direct children. Breadcrumbs navigate ownership; **Allocated work** is listed separately. Search names, kinds or `@aliases` to find elements with ancestor context. Results are paged in groups of 100. **Collapse all** folds the outline; **Locate** clears the filter and reveals the selected element's ancestry.
 
+**Data & interfaces** separates exchange nature from mechanism, supports bounded reusable types and typed defaults, and gives each interface item allocation its own protocol and artifact identity. Operation parameters have provider-side directions; qualified message paths distinguish repeated Record uses. Record/item/interface specialization preserves inherited identities. See the [data contract](docs/language.rst) for exact semantics and compatibility.
+
 The inspector exposes typed properties, references, ordered lists, aliases and UUID identity. Applying or navigating away attempts to commit the draft; invalid values remain editable. **Escaped strings (advanced)** uses quoted JSON escapes for exact tabs, line breaks and carriage returns, for example `"First\nSecond"`. UUID changes atomically update dependent references. Accepted model/source history retains up to 100 edits within an estimated 32 MiB history budget.
 
 Choose **Interaction**, **Functional exchange** or **Boundary exchange** in the diagram palette, then click the source and a highlighted compatible target, or drag between them. Functional exchanges use output/input ports; function cards create or reuse real ports atomically. Boundary exchanges use compatible component ports. Middle-button drag pans without losing the chosen source; arrow keys also pan while drawing with the canvas focused. Click empty space to restart, or Escape to cancel. Each completed connection is one model/source history operation; edit its name and carried items in Properties.
@@ -70,7 +72,7 @@ In the state view, **Select / move** drags vertices and containers without repar
 **Textual model** has a source-file folder tree, per-file drafts, syntax highlighting, live linting and explicit **Apply all**. Collapse/Locate navigate the hierarchy; collapsed folders retain draft and diagnostic indicators. Right-click a file for contextual actions. Projects can use relative includes to organize source into files. For example:
 
 ```text
-arcadia 3;
+arcadia 4;
 project harbor "Harbor assistance" {
     oa_entity control "Harbor control" {}
     oa_activity respond "Respond to requests" {