The all-sessions coverage GET dies: the per-session block is the coverage surface

Extraction-UX close-out interlude (master dispatch 2026-09-24, off UI's
ff1ec7a confirmation): nothing client-side consumes GET /api/graph/coverage
— the sidebar block and the chat-bar ring both read GET /api/chats/[id]'s
coverage block. The dead route (app/api/graph/coverage/route.ts) is
deleted; the manual-extract front door (POST /api/graph/coverage/extract)
stays by design.

No server helper was orphaned — the route was composition-only over
shared seams (chatStore, extractionStatuses, stores, coverageOf). The
sessionCoverage doc + the chats/[id] route comment now point at the
per-session block as THE coverage surface.

Pin (tests/coverage.test.ts): the route file's absence (prompt-overrides'
structural-pin precedent) + the Extract POST's survival — a merge cannot
resurrect the dead surface silently.

app/api/chats/[id]/route.ts

@@ -7,8 +7,9 @@ export async function GET(_req: Request, { params }: { params: Promise<{ id: str
 	// turnInFlight lets a returning client re-attach to a running turn
 	// (chat-handler write-ahead + registry — see src/server/turn-liveness.ts).
 	// coverage (extraction-UX redesign, 2026-09-24): the chat view's ring
-	// meter — one session's read of the same derivation /api/graph/coverage
+	// meter + sidebar block — THE coverage surface (the all-sessions GET
-	// serves for all sessions. getChat already 404'd, so the block exists.
+	// route died with the redesign; the Extract POST stays). getChat
+	// already 404'd, so the block exists.
 	return Response.json({ ...chat, turnInFlight: isTurnRunning(id), coverage: sessionCoverage(id) });
 }
 

app/api/graph/coverage/route.ts

@@ -1,40 +0,0 @@
-/**
- * GET /api/graph/coverage — the exact extraction coverage of every session
- * (vision-extraction-coverage.md, settled 2026-09-15): which sessions have
- * unextracted content, how much (tokens + message counts), and which runs
- * are in flight. "Uncovered" is DERIVED here per request — fingerprint the
- * current transcript, diff against the coverage ledger — never tracked as
- * a second ledger. This is the data behind the graph view's coverage panel
- * and its per-session "extract what's missing" buttons.
- */
-import type { UIMessage } from "ai";
-import { chatStore, extractionStatuses, stores } from "@/src/server";
-import { coverageOf } from "@/src/core";
-
-export const dynamic = "force-dynamic";
-
-export async function GET() {
-	const running = new Set(
-		extractionStatuses().filter((run) => run.kind === "chat").map((run) => run.chatId),
-	);
-	const entries = stores.graphStore.readCoverage();
-	const chats = chatStore.listChats().map((summary) => {
-		const record = chatStore.getChat(summary.id);
-		const messages = (record?.messages ?? []) as UIMessage[];
-		const cov = coverageOf(messages, entries, summary.id);
-		return {
-			chatId: summary.id,
-			title: summary.title,
-			updatedAt: summary.updatedAt,
-			totalMessages: cov.slots.length,
-			coveredMessages: cov.coveredCount,
-			uncoveredMessages: cov.uncoveredCount,
-			coveredTokens: cov.coveredTokens,
-			uncoveredTokens: cov.uncoveredTokens,
-			running: running.has(summary.id),
-		};
-	});
-	// Most uncovered first — the actionable sessions lead the panel.
-	chats.sort((a, b) => b.uncoveredTokens - a.uncoveredTokens || (a.updatedAt < b.updatedAt ? 1 : -1));
-	return Response.json({ chats });
-}

src/server/chats.ts

@@ -114,10 +114,11 @@ export async function deleteChatSession(chatId: string, mode: ChatDeleteMode): P
 }
 
 /** One session's coverage read (extraction-UX redesign, owner dispatch
- *  2026-09-24): the chat view's ring meter + popover data — the same
+ *  2026-09-24): the chat view's ring meter + popover data, scoped to one
- *  derivation the all-sessions list serves (/api/graph/coverage), scoped
+ *  chat (the all-sessions GET died with this redesign — nothing consumed
- *  to one chat. "Uncovered" stays DERIVED per request (fingerprint the
+ *  it once the sidebar and ring read here; the Extract POST stays).
- *  transcript, diff the coverage ledger — never dual-tracked).
+ *  Uncovered stays DERIVED per request (fingerprint the transcript,
+ *  diff the coverage ledger — never dual-tracked).
  *
  *  lastFoldedAt: the newest coverage row's fold timestamp — a cheap single
  *  pass over the chat's ledger rows (the ring popover's "last extraction"

tests/coverage.test.ts

@@ -1,5 +1,6 @@
 import assert from "node:assert/strict";
 import { describe, it } from "node:test";
+import * as fs from "node:fs";
 import type { UIMessage } from "ai";
 
 import {
@@ -156,4 +157,16 @@ describe("batchTag — deterministic, ref-stable, mutation-sensitive", () => {
 		const mutated = coverageSlots([user("m1", "aaaa!"), user("m2", "bbbb")]);
 		assert.notEqual(batchTag(slots), batchTag(mutated));
 	});
-});
+});
+describe("the all-sessions coverage GET is dead (extraction-UX close-out, 2026-09-24)", () => {
+	it("the route file is gone — the only coverage endpoint is the Extract POST", () => {
+		// UI confirmation (ff1ec7a): nothing client-side consumes the
+		// all-sessions list anymore — the sidebar block and the ring both
+		// read GET /api/chats/[id]'s coverage block. This pin guards against
+		// a merge resurrecting the dead surface.
+		assert.equal(fs.existsSync("app/api/graph/coverage/route.ts"), false, "the all-sessions GET route is deleted");
+		// stays by design: the manual-extract front door (sidebar block's
+		// Extract affordance) lives on.
+		assert.equal(fs.existsSync("app/api/graph/coverage/extract/route.ts"), true, "the Extract POST survives");
+	});
+});