feat: name leftover criterion on the matching Event Lineage node (v0.91.0)

AGENTS.md

@@ -75,12 +75,13 @@ in the same spirit) -- never against real data, per the hard rule above.
 against a live local stack (`make up`) and self-skip without one -- see
 [README.md](README.md#local-product-stack-docker-compose).
 
-Period leftover pairs (ADR 0017 / 0018) are computed in
+Period leftover pairs (ADR 0017 / 0018 / 0032) are computed in
 `lineageweave/leftover_pairs.py` from the residual after a real
 GRM/GPCM score, never invented. Missing cells stay out of the
 Gabriel factorization. Closest and farthest post–criterion pairs
 persist to `report_leftover_pair` and sit above the member list so
-a click opens that post.
+a click opens that post. An Event Lineage node that is a leftover
+pair also names the leftover criterion under the title.
 
 `frontend/` has its own toolchain (Node pinned via `frontend/mise.toml`,
 pnpm via Corepack -- do not add a second Node package manager or a

ARCHITECTURE.md

@@ -122,7 +122,8 @@ flowchart LR
   `rankweave_client.py`'s default transport raises
   `RankWeaveNotAvailable`. `GET /api/rankings` then returns
   `rankweave_not_available` and an empty ranking list. Hidden posts
-  are omitted from every channel. See ADR 0024.
+  are omitted from every channel. See ADR 0024. An Event Lineage
+  node that is also a leftover pair names that criterion (ADR 0032).
 
 ## Standards and citations
 

CHANGELOG.d/0.91.0-leftover-lineage-node.md

@@ -0,0 +1,8 @@
+# 0.91.0 — Leftover caption on the matching Event Lineage node
+
+## Added
+
+- Event Lineage nodes that are leftover pairs name the leftover
+  criterion (ADR 0032). After `make seed`, the leftover node reads
+  **Closest leftover · sales-lead** under the title; click opens
+  that post. A node that is not a leftover pair stays unmarked.

CHANGELOG.md

@@ -4,6 +4,16 @@ All notable changes to this project are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versioning follows
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.91.0] - 2026-08-18
+
+### Added
+
+- Event Lineage nodes that are leftover pairs name the leftover
+  criterion (ADR 0032). After `make seed`, the leftover node reads
+  **Closest leftover · sales-lead** under the title; click opens
+  that post. A node that is not a leftover pair stays unmarked.
+  Never invent a fused score or a theta.
+
 ## [0.75.0] - 2026-08-17
 
 ### Added

docs/adr/0032-leftover-pair-on-lineage-node.md

@@ -0,0 +1,53 @@
+# ADR 0032 — Name leftover on the matching Event Lineage node
+
+**Decision status:** Accepted
+**Date:** 2026-08-18
+
+## Context
+
+ADR 0018 puts leftover pairs above the period-report member list.
+Event Lineage is the surface a buyer scans to reconstruct the thread
+before they reach the home post list. The leftover post is already a
+DAG node; the node just does not name the leftover criterion.
+
+Do not invent a second leftover store. Do not invent a fused score
+or a theta. Do not change the existing `Open post: {title}`
+accessible name — leftover is a visible caption on the already-named
+control.
+
+## Decision
+
+When an authorized leftover pair names an Event Lineage node, that
+node shows `Closest leftover · {criterion}` or
+`Farthest leftover · {criterion}` under the post title.
+
+A node that is not a leftover pair stays unmarked. A leftover pair
+for a hidden post never reaches the DAG (ADR 0017 ABAC). A report
+fetch error clears leftover captions and leaves the reconstructed
+graph intact — never an invented pair.
+
+After `make seed`, the leftover Event Lineage node reads **Closest
+leftover · sales-lead** under the title; click still opens that post.
+
+Leftover evidence is the same authorized `leftover_pairs` already
+on the period-report payload. The home DAG and the popup DAG share
+that list.
+
+## Consequences
+
+Leftover buttons above the member list stay (ADR 0018). Home-row
+leftover stays on #254 / ADR 0031. Calendar leftover stays on #253 /
+ADR 0030. Rankings leftover stays on #252 / ADR 0029. This slice
+only labels the already-visible Event Lineage node.
+
+## Related
+
+Depends on [ADR 0017](0017-persist-lsirm-leftover-pairs.md) and
+[ADR 0018](0018-leftover-pair-report-ui.md).
+
+## References
+
+Jeon, M., Jin, I. H., Schweinberger, M., & Baugh, S. (2021). Mapping
+unobserved item–respondent interactions: A latent space item response
+model with interaction map. *Psychometrika, 86*(2), 378–403.
+https://doi.org/10.1007/s11336-021-09762-5

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "frontend",
   "private": true,
-  "version": "0.75.0",
+  "version": "0.91.0",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/App.css

@@ -215,6 +215,12 @@
   fill: canvastext;
 }
 
+.lineage-dag-leftover {
+  font-size: 9px;
+  letter-spacing: 0.02em;
+  fill: color-mix(in srgb, canvastext 72%, transparent);
+}
+
 .lineage-dag-node:focus {
   outline: none;
 }

frontend/src/App.test.tsx

@@ -56,6 +56,7 @@ describe("App, authenticated", () => {
   function stubBackend(options?: {
     admin?: boolean;
     calendarCommitments?: unknown[];
+    reportsUnavailable?: boolean;
     rankings?: {
       status?: "accepted" | "unavailable";
       status_reason?: string | null;
@@ -228,6 +229,14 @@ describe("App, authenticated", () => {
           }),
         );
       }
+      if (options?.reportsUnavailable && url.includes("/api/reports/")) {
+        return Promise.resolve(
+          new Response(JSON.stringify({ detail: "Period report unavailable" }), {
+            status: 503,
+            headers: { "Content-Type": "application/json" },
+          }),
+        );
+      }
       if (url.includes("/api/reports/compare/") && method === "GET") {
         return Promise.resolve(
           jsonResponse({
@@ -808,6 +817,31 @@ describe("App, authenticated", () => {
     await waitFor(() => expect(screen.getByText("The full body text.")).toBeInTheDocument());
   });
 
+  it("names leftover criterion on the matching Event Lineage node", async () => {
+    stubBackend();
+    render(<App />);
+
+    const leftoverNode = await screen.findByLabelText("Open post: Public post");
+    await waitFor(() => expect(leftoverNode).toHaveTextContent("Closest leftover · sales-lead"));
+    expect(leftoverNode).toHaveAccessibleName("Open post: Public post");
+    const unmarked = screen.getByLabelText("Open post: Unrelated: annual account review");
+    expect(unmarked).not.toHaveTextContent("leftover");
+
+    await userEvent.click(leftoverNode);
+
+    await waitFor(() => expect(screen.getByText("The full body text.")).toBeInTheDocument());
+  });
+
+  it("clears leftover badges on the DAG when the report fetch fails", async () => {
+    stubBackend({ reportsUnavailable: true });
+    render(<App />);
+
+    const leftoverNode = await screen.findByLabelText("Open post: Public post");
+    await waitFor(() => expect(screen.getByLabelText("A-100 lineage")).toBeInTheDocument());
+    expect(leftoverNode).not.toHaveTextContent("leftover");
+    expect(leftoverNode).toHaveAccessibleName("Open post: Public post");
+  });
+
   it("fetches and renders the post list, then opens a detail popup on click", async () => {
     const fetchMock = stubBackend();
 

frontend/src/App.tsx

@@ -52,6 +52,7 @@ import {
   type PostSummary,
   type RankingList,
   type RelatedNode,
+  type LeftoverPair,
   type VocEvidence,
 } from "./api";
 import { LineageDag } from "./LineageDag";
@@ -272,11 +273,13 @@ function EventLineageSection({
   graph,
   postId,
   onSelectPost,
+  leftoverPairs,
 }: {
   lineage: PostLineage | null;
   graph: LineageGraph | null;
   postId: string;
   onSelectPost?: (postId: string) => void;
+  leftoverPairs?: LeftoverPair[];
 }) {
   if (!lineage) return <p>Loading lineage...</p>;
   const scoped = graph ? subgraphForPost(graph, postId) : { nodes: [], edges: [] };
@@ -299,7 +302,7 @@ function EventLineageSection({
   return (
     <>
       {scoped.nodes.length > 0 && onSelectPost && (
-        <LineageDag graph={scoped} onSelectPost={onSelectPost} />
+        <LineageDag graph={scoped} onSelectPost={onSelectPost} leftoverPairs={leftoverPairs} />
       )}
       {hasLinks && (
         <ul className="lineage-list">
@@ -1087,13 +1090,15 @@ function PostDetailPopup({
   accessToken,
   canExtract,
   graph,
+  leftoverPairs,
   onClose,
   onSelectPost,
 }: {
   postId: string;
   accessToken: string;
   canExtract: boolean;
   graph: LineageGraph | null;
+  leftoverPairs?: LeftoverPair[];
   onClose: () => void;
   onSelectPost?: (postId: string) => void;
 }) {
@@ -1247,6 +1252,7 @@ function PostDetailPopup({
                 graph={graph}
                 postId={postId}
                 onSelectPost={onSelectPost}
+                leftoverPairs={leftoverPairs}
               />
             </section>
 
@@ -1425,10 +1431,12 @@ function ReportsPanel({
   accessToken,
   canRebuild,
   onSelectPost,
+  onLeftoverPairsChange,
 }: {
   accessToken: string;
   canRebuild: boolean;
   onSelectPost: (postId: string) => void;
+  onLeftoverPairsChange: (pairs: LeftoverPair[]) => void;
 }) {
   const [grouping, setGrouping] = useState("process_unit");
   const [period, setPeriod] = useState("2026-W02");
@@ -1455,9 +1463,13 @@ function ReportsPanel({
         setPayload(reports);
         setIndex(periods);
         setComparison(compared);
+        onLeftoverPairsChange(reports.reports.flatMap((row) => row.leftover_pairs ?? []));
       })
-      .catch((err) => setError(String(err)));
-  }, [accessToken, grouping, period]);
+      .catch((err) => {
+        setError(String(err));
+        onLeftoverPairsChange([]);
+      });
+  }, [accessToken, grouping, period, onLeftoverPairsChange]);
 
   async function handleRebuild() {
     setRebuilding(true);
@@ -1472,8 +1484,10 @@ function ReportsPanel({
       setPayload(reports);
       setIndex(periods);
       setComparison(compared);
+      onLeftoverPairsChange(reports.reports.flatMap((row) => row.leftover_pairs ?? []));
     } catch (err) {
       setError(String(err));
+      onLeftoverPairsChange([]);
     } finally {
       setRebuilding(false);
     }
@@ -1658,6 +1672,7 @@ function PostList({ accessToken }: { accessToken: string }) {
   const [graph, setGraph] = useState<LineageGraph | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [selectedPostId, setSelectedPostId] = useState<string | null>(null);
+  const [leftoverPairs, setLeftoverPairs] = useState<LeftoverPair[]>([]);
   const [canRebuild, setCanRebuild] = useState(false);
   const [rebuilding, setRebuilding] = useState(false);
   const [rebuildError, setRebuildError] = useState<string | null>(null);
@@ -1691,7 +1706,12 @@ function PostList({ accessToken }: { accessToken: string }) {
     <>
       <RankingsPanel accessToken={accessToken} onSelectPost={setSelectedPostId} />
       <CalendarPanel accessToken={accessToken} onSelectPost={setSelectedPostId} />
-      <ReportsPanel accessToken={accessToken} canRebuild={canRebuild} onSelectPost={setSelectedPostId} />
+      <ReportsPanel
+        accessToken={accessToken}
+        canRebuild={canRebuild}
+        onSelectPost={setSelectedPostId}
+        onLeftoverPairsChange={setLeftoverPairs}
+      />
       <section className="popup-section lineage-home">
         <div className="lineage-home-header">
           <h2>Event Lineage</h2>
@@ -1703,7 +1723,13 @@ function PostList({ accessToken }: { accessToken: string }) {
         </div>
         {rebuildError && <p className="error">{rebuildError}</p>}
         {!graph && <p>Loading lineage graph...</p>}
-        {graph && <LineageDag graph={graph} onSelectPost={setSelectedPostId} />}
+        {graph && (
+          <LineageDag
+            graph={graph}
+            onSelectPost={setSelectedPostId}
+            leftoverPairs={leftoverPairs}
+          />
+        )}
       </section>
       <ul className="post-list">
         {posts.map((post) => (
@@ -1726,6 +1752,7 @@ function PostList({ accessToken }: { accessToken: string }) {
           accessToken={accessToken}
           canExtract={canRebuild}
           graph={graph}
+          leftoverPairs={leftoverPairs}
           onClose={() => setSelectedPostId(null)}
           onSelectPost={setSelectedPostId}
         />

frontend/src/LineageDag.tsx

@@ -1,4 +1,5 @@
-import type { LineageGraph } from "./api";
+import type { LeftoverPair, LineageGraph } from "./api";
+import { leftoverBadgeText, leftoverPairsForPost } from "./leftoverCaption";
 import { layoutLineageDag } from "./lineageLayout";
 
 function truncateLabel(label: string): string {
@@ -8,9 +9,11 @@ function truncateLabel(label: string): string {
 export function LineageDag({
   graph,
   onSelectPost,
+  leftoverPairs,
 }: {
   graph: LineageGraph;
   onSelectPost: (postId: string) => void;
+  leftoverPairs?: LeftoverPair[];
 }) {
   const groups = layoutLineageDag(graph);
   if (graph.nodes.length === 0) {
@@ -50,6 +53,8 @@ export function LineageDag({
               })}
               {group.nodes.map((node) => {
                 const kind = node.is_branch_point ? "branch" : node.is_root ? "root" : "node";
+                const leftoverForNode = leftoverPairsForPost(leftoverPairs, node.id);
+                const leftoverTitles = leftoverForNode.map(leftoverBadgeText);
                 return (
                   <g
                     key={node.id}
@@ -70,7 +75,21 @@ export function LineageDag({
                     <text x={12} y={4}>
                       {truncateLabel(node.label)}
                     </text>
-                    <title>{`${node.label} — ${node.occurred_at.slice(0, 10)}`}</title>
+                    {leftoverForNode.map((pair, index) => (
+                      <text
+                        key={`${pair.pair_kind}:${pair.criterion_code}`}
+                        className="lineage-dag-leftover"
+                        x={12}
+                        y={16 + index * 12}
+                      >
+                        {leftoverBadgeText(pair)}
+                      </text>
+                    ))}
+                    <title>
+                      {leftoverTitles.length > 0
+                        ? `${node.label} — ${node.occurred_at.slice(0, 10)} — ${leftoverTitles.join(" · ")}`
+                        : `${node.label} — ${node.occurred_at.slice(0, 10)}`}
+                    </title>
                   </g>
                 );
               })}