TanStack · tannerlinsley · Aug 12, 2026 · Aug 12, 2026 · Aug 12, 2026 · Aug 12, 2026
diff --git a/.changeset/calm-radial-focus.md b/.changeset/calm-radial-focus.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/charts': minor
+---
+
+Add angular grouped focus for radial charts and geometry-backed arc tooltips.
diff --git a/API-FRICTION.md b/API-FRICTION.md
@@ -5,7 +5,7 @@ observed difficulty from examples, production migrations, tests, and agent
 evaluations so later API, documentation, and TanStack Intent skill work is
 based on evidence.
 
-Last updated: 2026-08-11
+Last updated: 2026-08-12
 
 ## Triage rule
 
@@ -307,6 +307,8 @@ Each entry records:
 | F-268 | Animated arc flags became invalid fractional path values       | API                   | resolved   |
 | F-269 | Angular mounted its browser host during server rendering       | API                   | resolved   |
 | F-270 | Catalog migration left generated release evidence stale        | Tooling               | resolved   |
+| F-271 | Radial focus collapsed angular cross-sections to centroids     | API                   | resolved   |
+| F-272 | Pointer probes armed between transient inactive frames         | Tooling               | resolved   |
 
 ## Findings
 
@@ -7954,3 +7956,52 @@ Each entry records:
 - Verification: the focused roadmap test and catalog preview check pass. The
   only rendered asset change normalizes synchronized-cursor point keys from
   timestamp labels to the migrated ISO date labels; geometry is unchanged.
+
+### F-271 — Radial focus collapsed angular cross-sections to centroids
+
+- Status: resolved
+- Severity: high
+- Owner: API
+- Observed in: radial tooltip interaction review
+- Friction: polar lines, areas, and dots exposed only Cartesian centroid
+  anchors to the default nearest-point resolver. Moving around one semantic
+  angle could select a different radius or adjacent angle, and grouped radial
+  tooltips had no equivalent of `group-x`. `radialArc` also emitted a centroid
+  without attaching its already available painted boundary, so pie and donut
+  focus could disagree with the visible slice.
+- Decision: export `focusGroupAngle` from the exact polar subpath. It selects
+  the nearest bounded radial ray, uses radius distance as the primary-point
+  tie-breaker, groups one point per series at the same semantic angle, and
+  orders keyboard tasks angularly. Keep the strategy out of ordinary and
+  universal barrels. Attach the existing D3-replayed interaction boundary to
+  every `radialArc`, including authored generators.
+- Verification: focused polar tests resolve two series from a one-pixel
+  angular ray while both anchors are farther away, preserve the closest radius
+  as primary, and reduce keyboard navigation to one task per semantic angle.
+  Arc tests hit the painted annulus at zero fallback distance, reject its hole,
+  and reuse the exact point attached to the scene geometry. Polar, radial-bar,
+  sunburst, callable-surface, documentation, and root TypeScript checks pass.
+  The measured polar arc is 15.06 KiB gzip, gauge 24.08, radial labels 20.66,
+  radial bars 24.17, and polar line/scatter 25.28; their isolated ceilings now
+  record those reviewed interaction costs while the locked representative-mark
+  bundle remains unchanged at 25.59 KiB gzip.
+
+### F-272 — Pointer probes armed between transient inactive frames
+
+- Status: resolved
+- Severity: high
+- Owner: Tooling
+- Observed in: radial-focus release PR stress partition 3
+- Friction: the Chart.js grouped-pointer cell moved outside the chart and
+  accepted its first inactive frame as settled. Its activation timer then
+  observed the tooltip active again and failed before measuring the target.
+  The exact cell passed locally, confirming a scheduling race rather than a
+  radial-focus regression, but the correctness failure was intentionally not
+  retryable.
+- Decision: require two consecutive inactive animation frames before arming
+  pointer activation timing. Keep renderer and correctness failures
+  non-retryable; this stabilizes the measured precondition instead of hiding a
+  failed sample with another attempt.
+- Verification: the exact Chart.js grouped-pointer cell and the complete quick
+  partition 3 pass with trusted activation, exact grouped series values, and
+  zero recovered retries.
diff --git a/benchmarks/comparison/bundle-baseline.json b/benchmarks/comparison/bundle-baseline.json
@@ -1,8 +1,8 @@
 {
   "schemaVersion": 4,
-  "generatedAt": "2026-08-11T23:49:36.793Z",
+  "generatedAt": "2026-08-12T23:00:29.524Z",
   "packageVersions": {
-    "tanstack": "0.11.0",
+    "tanstack": "0.11.2",
     "chartjs": "4.5.1",
     "echarts": "6.1.0",
     "recharts": "3.10.1",
@@ -11,8 +11,8 @@
   "sources": {
     "tanstack": {
       "kind": "workspace",
-      "revision": "02e24867f1699fa918fd49eaedfad64bc3f4e9e5",
-      "inputDigest": "sha256:790fc8c0e954afbba943d637d43b665739d2438d2cc6c341e81613baad327508"
+      "revision": "b9d8c541ef6a94afdc1812555ee0e4459c81d140",
+      "inputDigest": "sha256:52b55a904317f891ec664992193770fd9468bddddeef1e8f9fe10ec113051b05"
     },
     "chartjs": {
       "kind": "package",

diff --git a/benchmarks/comparison/stress/README.md b/benchmarks/comparison/stress/README.md
@@ -146,7 +146,8 @@ and streaming inputs are source-accounted independently.
 Multi-series output gates exact ordered series identity, stable color
 ownership, explicit x-domain changes, and per-series vertex counts. Trusted
 pointer checks validate the exact focused x and every series value on the
-initial chart and again after reorder, append, and visibility updates.
+initial chart and again after reorder, append, and visibility updates. Pointer
+activation timing starts only after two consecutive inactive animation frames.
 
 Cross-library timing rank is informational. Browser timing, long tasks, and
 retained-memory deltas are meaningful only within the same run, machine, and

diff --git a/benchmarks/conformance/previews/manifest.json b/benchmarks/conformance/previews/manifest.json
@@ -2,7 +2,7 @@
   "schemaVersion": 1,
   "width": 288,
   "height": 192,
-  "sourceHash": "e51640f5fc66d37a982722a282685167d084940132c429f7a2515f16f28714f3",
+  "sourceHash": "93452895c364c1dd0cc6b824137d35b8c43e0a022dca544e38dccea52b94fb88",
   "assets": [
     {
       "id": "01-line-gaps",

diff --git a/docs/comparison.md b/docs/comparison.md
@@ -12,14 +12,14 @@ turning untested behavior into a checkmark.
 
 | Library                                                                                | Package              | Measured source     |
 | -------------------------------------------------------------------------------------- | -------------------- | ------------------- |
-| [TanStack Charts](./overview.md)                                                       | `@tanstack/charts`   | workspace `02e2486` |
+| [TanStack Charts](./overview.md)                                                       | `@tanstack/charts`   | workspace `b9d8c54` |
 | [Chart.js](https://www.chartjs.org/docs/latest/)                                       | `chart.js`           | npm `4.5.1`         |
 | [Apache ECharts](https://echarts.apache.org/handbook/en/best-practices/canvas-vs-svg/) | `echarts`            | npm `6.1.0`         |
 | [Recharts](https://recharts.github.io/en-US/)                                          | `recharts`           | npm `3.10.1`        |
 | [Observable Plot](https://observablehq.com/plot/features/plots)                        | `@observablehq/plot` | npm `0.6.17`        |
 
 The competitor versions are exact package pins, not latest versions inferred
-at page render time. The measured TanStack workspace revision is `02e2486`.
+at page render time. The measured TanStack workspace revision is `b9d8c54`.
 
 ## Capability matrix
 
@@ -90,7 +90,7 @@ output model.
 
 ## Bundle snapshot
 
-Baseline date: `2026-08-11`.
+Baseline date: `2026-08-12`.
 
 Controlled ranges cover 12 independently built, minified browser consumers:
 line, bar, area, and scatter at basic, interactive, and advanced tiers. Only

diff --git a/docs/guides/tooltips-and-focus.md b/docs/guides/tooltips-and-focus.md
@@ -48,6 +48,29 @@ category. A sparse snapped cursor can opt into
 `maxFocusDistance: Number.POSITIVE_INFINITY`; keep the finite default when
 empty space should mean no focus.
 
+## Angular focus
+
+Use `focusGroupAngle` for the radial equivalent of `group-x`:
+
+```ts
+import { defineChart, type ChartDefinition } from '@tanstack/charts'
+import { focusGroupAngle } from '@tanstack/charts/polar'
+import { tooltip } from '@tanstack/charts/tooltip'
+
+declare const radialDefinition: ChartDefinition
+
+const interactiveDefinition = defineChart(radialDefinition, {
+  focus: focusGroupAngle,
+  tooltip,
+})
+```
+
+The nearest radial ray selects the semantic angle, the closest radius becomes
+primary, and the tooltip receives one point per series at that angle. The
+strategy uses the same finite `maxFocusDistance` policy as axis grouping.
+Ordinary pie and donut charts can keep default nearest focus: `radialArc`
+attaches the exact painted slice geometry, including the donut hole.
+
 Default `primary` and `group` presentation follows the canonical focused scene
 points. Equal x/y/series values in another facet do not implicitly paint a
 second focus marker. To synchronize a visual cursor across facets without

diff --git a/docs/reference/focus-and-interaction.md b/docs/reference/focus-and-interaction.md
@@ -139,6 +139,12 @@ or direct strategy use. The exact exported objects receive the same host-level
 containment behavior as their presets. A strategy that wraps or copies one of
 them is custom and owns its complete pointer resolution.
 
+`focusGroupAngle` is available from `@tanstack/charts/polar`. It resolves the
+nearest radial ray, groups points with the same semantic angle value, and
+orders keyboard tasks by angle. Use it for grouped radar, polar-line, and
+radial-dot tooltips. Painted `radialArc` geometry already participates in
+default nearest focus.
+
 ## Crosshair guides
 
 `crosshair` is a data-less presentation mark. It follows the chart's resolved

diff --git a/docs/reference/index.md b/docs/reference/index.md
@@ -159,7 +159,7 @@ aggregate `/scales` export.
 | `@tanstack/charts/motion`               | `motion`, `ChartMotionOptions`, and renderer-neutral motion types                                                                                                                                                               |
 | `@tanstack/charts/network/force`        | `forceLayout`, built-in descriptors, named D3-compatible force factories, private working-clone context, settled node/link result, and lineage types                                                                            |
 | `@tanstack/charts/network/sankey`       | `sankeyDiagram`, shorthand and callable alignment types, responsive layout options, immutable node/link values, comparator contexts, and lineage types                                                                          |
-| `@tanstack/charts/polar`                | `pie`, `polar`, `radialArc`, `radialBarRadius`, `radialBarAngle`, other radial marks, and radial/angle guides                                                                                                                   |
+| `@tanstack/charts/polar`                | `pie`, `polar`, `focusGroupAngle`, `radialArc`, `radialBarRadius`, `radialBarAngle`, other radial marks, and radial/angle guides                                                                                                |
 | `@tanstack/charts/universal`            | Common root authoring, runtime, scene, and static SVG values without browser hosts or adapters                                                                                                                                  |
 | `@tanstack/charts/reconcile`            | `reconcileChartSvg`, `reconcileChartSvgFragment`                                                                                                                                                                                |
 | `@tanstack/charts/rect`                 | `rect`, `cell`                                                                                                                                                                                                                  |

diff --git a/docs/reference/marks/polar.md b/docs/reference/marks/polar.md
@@ -8,6 +8,7 @@ Polar marks are available only from the capability subpath:
 ```ts
 import {
   angleGrid,
+  focusGroupAngle,
   pie,
   polar,
   radialArc,
@@ -82,6 +83,28 @@ resize.
 The outer chart omits `x` and `y`. Cartesian axes do not participate in the
 internal polar scales.
 
+## `focusGroupAngle`
+
+```ts
+import { defineChart, type ChartDefinition } from '@tanstack/charts'
+import { focusGroupAngle } from '@tanstack/charts/polar'
+import { tooltip } from '@tanstack/charts/tooltip'
+
+declare const definition: ChartDefinition
+
+const interactiveDefinition = defineChart(definition, {
+  focus: focusGroupAngle,
+  tooltip,
+})
+```
+
+`focusGroupAngle` is the polar equivalent of `group-x`. Pointer resolution
+uses the nearest radial ray instead of the nearest point anchor, then returns
+one point per series with the same semantic angle value. The closest radius is
+primary. Keyboard navigation visits one representative per angle in angular
+order. `maxFocusDistance` is the scene-pixel distance from the pointer to the
+ray; set it to `Number.POSITIVE_INFINITY` for continuous angular snapping.
+
 ## `pie`
 
 ```ts
@@ -154,6 +177,11 @@ function radialArc<TDatum>(
 | `strokeDasharray` | Boundary dash array                                            |
 | `opacity`         | Whole-arc opacity                                              |
 
+Each arc attaches its sampled painted boundary to its interaction point.
+Default nearest focus therefore follows the visible slice, including holes,
+rounded corners, reversed sweeps, and custom D3 generators, instead of using
+only the centroid anchor.
+
 Use the native `pie` transform for flat typed rows with source lineage. D3
 `pie` output remains valid interoperability input because its `startAngle`,
 `endAngle`, and `padAngle` fields are also the channels this mark needs. A pie,

diff --git a/packages/charts-core/docs/comparison.md b/packages/charts-core/docs/comparison.md
@@ -12,14 +12,14 @@ turning untested behavior into a checkmark.
 
 | Library                                                                                | Package              | Measured source     |
 | -------------------------------------------------------------------------------------- | -------------------- | ------------------- |
-| [TanStack Charts](./overview.md)                                                       | `@tanstack/charts`   | workspace `02e2486` |
+| [TanStack Charts](./overview.md)                                                       | `@tanstack/charts`   | workspace `b9d8c54` |
 | [Chart.js](https://www.chartjs.org/docs/latest/)                                       | `chart.js`           | npm `4.5.1`         |
 | [Apache ECharts](https://echarts.apache.org/handbook/en/best-practices/canvas-vs-svg/) | `echarts`            | npm `6.1.0`         |
 | [Recharts](https://recharts.github.io/en-US/)                                          | `recharts`           | npm `3.10.1`        |
 | [Observable Plot](https://observablehq.com/plot/features/plots)                        | `@observablehq/plot` | npm `0.6.17`        |
 
 The competitor versions are exact package pins, not latest versions inferred
-at page render time. The measured TanStack workspace revision is `02e2486`.
+at page render time. The measured TanStack workspace revision is `b9d8c54`.
 
 ## Capability matrix
 
@@ -90,7 +90,7 @@ output model.
 
 ## Bundle snapshot
 
-Baseline date: `2026-08-11`.
+Baseline date: `2026-08-12`.
 
 Controlled ranges cover 12 independently built, minified browser consumers:
 line, bar, area, and scatter at basic, interactive, and advanced tiers. Only

diff --git a/packages/charts-core/docs/guides/tooltips-and-focus.md b/packages/charts-core/docs/guides/tooltips-and-focus.md
@@ -48,6 +48,29 @@ category. A sparse snapped cursor can opt into
 `maxFocusDistance: Number.POSITIVE_INFINITY`; keep the finite default when
 empty space should mean no focus.
 
+## Angular focus
+
+Use `focusGroupAngle` for the radial equivalent of `group-x`:
+
+```ts
+import { defineChart, type ChartDefinition } from '@tanstack/charts'
+import { focusGroupAngle } from '@tanstack/charts/polar'
+import { tooltip } from '@tanstack/charts/tooltip'
+
+declare const radialDefinition: ChartDefinition
+
+const interactiveDefinition = defineChart(radialDefinition, {
+  focus: focusGroupAngle,
+  tooltip,
+})
+```
+
+The nearest radial ray selects the semantic angle, the closest radius becomes
+primary, and the tooltip receives one point per series at that angle. The
+strategy uses the same finite `maxFocusDistance` policy as axis grouping.
+Ordinary pie and donut charts can keep default nearest focus: `radialArc`
+attaches the exact painted slice geometry, including the donut hole.
+
 Default `primary` and `group` presentation follows the canonical focused scene
 points. Equal x/y/series values in another facet do not implicitly paint a
 second focus marker. To synchronize a visual cursor across facets without

diff --git a/packages/charts-core/docs/reference/focus-and-interaction.md b/packages/charts-core/docs/reference/focus-and-interaction.md
@@ -139,6 +139,12 @@ or direct strategy use. The exact exported objects receive the same host-level
 containment behavior as their presets. A strategy that wraps or copies one of
 them is custom and owns its complete pointer resolution.
 
+`focusGroupAngle` is available from `@tanstack/charts/polar`. It resolves the
+nearest radial ray, groups points with the same semantic angle value, and
+orders keyboard tasks by angle. Use it for grouped radar, polar-line, and
+radial-dot tooltips. Painted `radialArc` geometry already participates in
+default nearest focus.
+
 ## Crosshair guides
 
 `crosshair` is a data-less presentation mark. It follows the chart's resolved

diff --git a/packages/charts-core/docs/reference/index.md b/packages/charts-core/docs/reference/index.md
@@ -159,7 +159,7 @@ aggregate `/scales` export.
 | `@tanstack/charts/motion`               | `motion`, `ChartMotionOptions`, and renderer-neutral motion types                                                                                                                                                               |
 | `@tanstack/charts/network/force`        | `forceLayout`, built-in descriptors, named D3-compatible force factories, private working-clone context, settled node/link result, and lineage types                                                                            |
 | `@tanstack/charts/network/sankey`       | `sankeyDiagram`, shorthand and callable alignment types, responsive layout options, immutable node/link values, comparator contexts, and lineage types                                                                          |
-| `@tanstack/charts/polar`                | `pie`, `polar`, `radialArc`, `radialBarRadius`, `radialBarAngle`, other radial marks, and radial/angle guides                                                                                                                   |
+| `@tanstack/charts/polar`                | `pie`, `polar`, `focusGroupAngle`, `radialArc`, `radialBarRadius`, `radialBarAngle`, other radial marks, and radial/angle guides                                                                                                |
 | `@tanstack/charts/universal`            | Common root authoring, runtime, scene, and static SVG values without browser hosts or adapters                                                                                                                                  |
 | `@tanstack/charts/reconcile`            | `reconcileChartSvg`, `reconcileChartSvgFragment`                                                                                                                                                                                |
 | `@tanstack/charts/rect`                 | `rect`, `cell`                                                                                                                                                                                                                  |