diff --git a/.changeset/adr-0021-single-form-cutover.md b/.changeset/adr-0021-single-form-cutover.md
new file mode 100644
index 000000000..2781ab719
--- /dev/null
+++ b/.changeset/adr-0021-single-form-cutover.md
@@ -0,0 +1,25 @@
+---
+"@objectstack/spec": major
+---
+
+ADR-0021 single-form cutover (BREAKING): the inline analytics author surface is
+removed — every dashboard widget, report, and list-chart must now bind a
+semantic `dataset` and select dimensions/measures **by name**.
+
+Removed from the spec:
+
+- **DashboardWidget** — `object`, `categoryField`, `categoryGranularity`,
+  `valueField`, `aggregate`, `measures` (and the `WidgetMeasure` schema/type).
+  `dataset` + `values` are now required; `filter` is the presentation-scope
+  runtimeFilter; `dimensions` / `compareTo` are retained.
+- **Report** — top-level (and joined-block) `objectName`, `columns`,
+  `groupingsDown`, `groupingsAcross`, `filter`. A non-joined report now requires
+  `dataset` + `values`; `rows` are the dimensions.
+- **ListChart** — `xAxisField`, `yAxisFields`, `aggregation`, `groupByField`.
+  `dataset` + `values` are now required.
+
+Migration: replace the inline query with a `defineDataset(...)` and reference it
+by name. A flat record listing (the former `tabular` report / inline list) is an
+object-bound ListView (ADR-0017), not an analytics dataset. See
+`docs/adr/0021-analytics-dataset-semantic-layer.md` and the
+`content/docs/guides/analytics-datasets.mdx` guide.