practice fix follow-up — the picker lists EVERY birth-session group (owner ruling)

Owner escalation on deviation 1: practice availability must not
inherit a visual-rendering threshold. graphClusters() now runs
birthSessionPartition(snap.nodes) directly (same size-desc/id-asc
ordering) instead of reading the snapshot's MIN_CLUSTER_SIZE-filtered
clusters array — MIN_CLUSTER_SIZE stays a hull-drawing rule only.
Label join mirrors the snapshot's (chat title / notes path, null when
the naming record is gone). Contract doc + architecture.md sentence
corrected to match; empty-picker copy reworded ('once a session births
its first proposition' — no 3+ mechanics). Render pins: new empty line
+ a 1- and 2-proposition group listing pin. 1130/1130, tsc 0, lint 0,
build 0.

components/practice-dialog.tsx

@@ -104,7 +104,7 @@ export function PracticeDialogBody({
 					))}
 					{clusters.length === 0 && (
 						<div className="px-3 py-2 text-sm text-muted-foreground">
-							No clusters yet — a cluster appears once a session births 3+ propositions.
+							No clusters yet — a cluster appears once a session births its first proposition.
 						</div>
 					)}
 				</div>

docs/architecture.md

@@ -380,7 +380,7 @@ Practice turns the graph into problem sets the learner reasons through out loud.
 
 **The jobs pattern — registry, not JobRecords.** Practice runs are NOT Workbench jobs: no `JobStore` records, no steer messages, nothing ever wakes the teacher — a practice run isn't chat-scoped (a set outlives its birth session and has no lesson to re-enter; its result is itself, persisted in its own store and read by its own page). What it shares with the Workbench is the observability surface: a `globalThis` run registry (the module-instance idiom — `__lhPracticeRuns`), one row per set-phase (`setId:generation`, `setId:grading`), feeding the activity dock (GraduationCap rows; abort is set-scoped and idempotent; a boot sweep marks orphaned `partitioning`/`generating` sets as `error "Interrupted (server restarted)"` — the job runner's crash-honesty at set grain). Store writes serialize behind a per-set mutex; the pipeline is the sole writer of `data/practice`.
 
-**API + UI.** Creation is GRAPH-DOMAIN, not chat-domain (owner ruling 2026-09-29: "problem sets always take in nodes — graph objects"): `POST /api/practice/sets` takes `{nodeIds, params, title?}` ONLY — no chatId, no clusterId; the UI resolves a picked cluster to its member node ids and passes the cluster's label as the title. `GET /api/graph/clusters` serves the picker: the birth-session clusters the graph view renders (`graphSnapshot`'s clusters verbatim — same ordering, same MIN_CLUSTER_SIZE presentation filter), each as `{key, kind: "chat"|"notes", label, nodeIds, nodeCount}`; a cluster whose naming record is gone keeps `label: null` — honest, never guessed. 202 `{id}` with generation fire-and-forget; 400 empty selection (empty intersection with live nodes — the vanished-nodes edge) / bad params; 503 model/key refusal. `GET /api/practice/sets` · `GET/DELETE /api/practice/sets/[id]` (delete aborts live runs first) · `POST /api/practice/sets/[id]/answers` (202; 409 when not ready). Surfaces: `/practice` (the list — status/counts rows, delete confirm, the new-set dialog with the three dials and the cluster picker — the ONLY creation entry for now; the graph-view cluster entry comes later with the free-form selection UI) and `/practice/[id]` (the exam page — numbered problems, markdown statements with math healing at the display seam, a textarea + focus-gated dictation bar per problem, one Submit per set, the post-grade reveal). Entry: the sidebar's Practice nav row.
+**API + UI.** Creation is GRAPH-DOMAIN, not chat-domain (owner ruling 2026-09-29: "problem sets always take in nodes — graph objects"): `POST /api/practice/sets` takes `{nodeIds, params, title?}` ONLY — no chatId, no clusterId; the UI resolves a picked cluster to its member node ids and passes the cluster's label as the title. `GET /api/graph/clusters` serves the picker: the birth-session partition itself (`birthSessionPartition`, same ordering — size desc, ties by id) — EVERY group regardless of size (owner ruling, same evening: MIN_CLUSTER_SIZE is a hull-drawing rule; practice availability must not inherit a visual threshold), each as `{key, kind: "chat"|"notes", label, nodeIds, nodeCount}`; a cluster whose naming record is gone keeps `label: null` — honest, never guessed. 202 `{id}` with generation fire-and-forget; 400 empty selection (empty intersection with live nodes — the vanished-nodes edge) / bad params; 503 model/key refusal. `GET /api/practice/sets` · `GET/DELETE /api/practice/sets/[id]` (delete aborts live runs first) · `POST /api/practice/sets/[id]/answers` (202; 409 when not ready). Surfaces: `/practice` (the list — status/counts rows, delete confirm, the new-set dialog with the three dials and the cluster picker — the ONLY creation entry for now; the graph-view cluster entry comes later with the free-form selection UI) and `/practice/[id]` (the exam page — numbered problems, markdown statements with math healing at the display seam, a textarea + focus-gated dictation bar per problem, one Submit per set, the post-grade reveal). Entry: the sidebar's Practice nav row.
 
 **Model wiring.** Three roles — `partitioner`, `problemGenerator`, `grader` — all pinned to the **strong** slot (quality-critical, one settings edit from cheap) and in `BACKGROUND_MODEL_ROLES` (per-role overrides). The stage agents are single-submit loops on the shared `runSubmitAgent` seam (`submit-agent.ts`, extracted from extraction for exactly this): a `validate` hook turns a bad submit into a tool-input error the model retries against, within `maxTurns 4`; exhaustion fails the stage honestly (the set says so, the chains re-run cleanly on a new set).
 

src/core/contracts/graph.ts

@@ -260,10 +260,11 @@ export interface Cluster {
 
 /** One birth-session cluster as the practice picker consumes it (owner
  *  ruling 2026-09-29: problem sets take NODES — the UI resolves a picked
- *  cluster to its member ids). Same grouping the graph view renders
- *  (birthSessionPartition semantics, MIN_CLUSTER_SIZE presentation
- *  filter included); `label` is null when the naming record is gone —
- *  honest, never guessed (the graph view renders those unlabeled). */
+ *  cluster to its member ids). EVERY birth-session group regardless of
+ *  size (owner ruling, same evening: MIN_CLUSTER_SIZE is a hull-drawing
+ *  rule — practice availability must not inherit a visual threshold);
+ *  `label` is null when the naming record is gone — honest, never
+ *  guessed (the graph view renders those unlabeled). */
 export interface GraphClusterGroup {
 	/** The birth session's id — a chatId or a notes source id. */
 	key: string;

src/server/graph.ts

@@ -4,6 +4,7 @@ import type { GraphClusterGroup, GraphSnapshot } from "../core/contracts.ts";
 import type { GraphCostSummary } from "../core/cost-summary.ts";
 import { graphCostSummary } from "../core/cost-summary.ts";
 import { graphSnapshot } from "../core/graph.ts";
+import { birthSessionPartition } from "../core/session-clusters.ts";
 import {
 	deleteNodeTraces,
 	nodeDeletionImpact,
@@ -23,21 +24,23 @@ export function graphView(): GraphSnapshot {
 	return graphSnapshot(stores);
 }
 
-/** GET /api/graph/clusters — the birth-session groups the graph view
- *  renders, resolved to node ids for the practice picker (owner ruling
- *  2026-09-29: cluster→nodeIds resolves in the UI; the API stays
- *  graph-domain). Reuses the snapshot's clustering verbatim — same
- *  ordering (size desc, ties by id) and the same MIN_CLUSTER_SIZE
- *  presentation filter the canvas honors. A corrupt/empty graph is an
- *  empty list. */
+/** GET /api/graph/clusters — the birth-session groups, resolved to node
+ *  ids for the practice picker (owner ruling 2026-09-29: cluster→nodeIds
+ *  resolves in the UI; the API stays graph-domain). EVERY group is
+ *  listed regardless of size (owner ruling, same evening:
+ *  MIN_CLUSTER_SIZE is a hull-DRAWING rule — practice availability must
+ *  not inherit a visual threshold), with the partition's own ordering
+ *  (size desc, ties by id asc). The label join mirrors the snapshot's:
+ *  chat title / notes file path, null when the naming record is gone —
+ *  honest, never guessed. A corrupt/empty graph is an empty list. */
 export function graphClusters(): GraphClusterGroup[] {
 	const snap = graphSnapshot(stores);
-	return snap.clusters.map((cluster) => ({
-		key: cluster.id,
-		kind: cluster.id in snap.sessions ? "chat" : "notes",
-		label: cluster.label,
-		nodeIds: cluster.members,
-		nodeCount: cluster.members.length,
+	return birthSessionPartition(snap.nodes).map((group) => ({
+		key: group.id,
+		kind: group.id in snap.sessions ? "chat" : "notes",
+		label: snap.sessions[group.id] ?? snap.fileSources[group.id] ?? null,
+		nodeIds: group.members,
+		nodeCount: group.members.length,
 	}));
 }
 

tests/render-practice.test.tsx

@@ -46,6 +46,15 @@ function clusters(): GraphClusterGroup[] {
 	];
 }
 
+/** Small groups are listable (owner ruling: practice availability never
+ *  inherits the hull-drawing threshold). */
+function smallClusters(): GraphClusterGroup[] {
+	return [
+		{ key: "chat_2", kind: "chat", label: "One-off question", nodeIds: ["n20"], nodeCount: 1 },
+		{ key: "chat_3", kind: "chat", label: "Quick exchange", nodeIds: ["n30", "n31"], nodeCount: 2 },
+	];
+}
+
 function stubProblem(id: string, chains: string[]): Problem {
 	return { id, chains, statement: "", solution: "", rubric: "", status: "generating" };
 }
@@ -129,6 +138,15 @@ describe("PracticeDialogBody — creation (cluster picker)", () => {
 	it("an empty graph is an honest empty list", () => {
 		const html = renderToStaticMarkup(<PracticeDialogBody {...base} clusters={[]} />);
 		assert.ok(html.includes("No clusters yet"));
+		assert.ok(html.includes("once a session births its first proposition"), "no 3+ mechanics in copy");
+	});
+
+	it("1- and 2-proposition groups appear — no hull threshold in the picker", () => {
+		const html = renderToStaticMarkup(<PracticeDialogBody {...base} clusters={smallClusters()} />);
+		assert.ok(html.includes('data-testid="practice-cluster-chat_2"'), "singleton group listed");
+		assert.ok(html.includes("1 propositions"));
+		assert.ok(html.includes('data-testid="practice-cluster-chat_3"'), "pair group listed");
+		assert.ok(html.includes("2 propositions"));
 	});
 
 	it("empty selection (vanished nodes) renders the honest inline line", () => {