diff --git a/apps/cli/release-topics.ts b/apps/cli/release-topics.ts
index 7de4e3b..dc76800 100755
--- a/apps/cli/release-topics.ts
+++ b/apps/cli/release-topics.ts
@@ -14,17 +14,21 @@
  * the same day.
  *
  * Each release is a changelog snapshot at that instant: the issue's problems
- * (a topic's sub-issues plus those since re-parented into Review issues, or a
- * review's sub-issues in solve order — see topics.ts) grouped as closed on the
- * finish day (ET), closed earlier, and open at release, each with its set,
- * difficulty, and the solution files as they stood in the tagged commit — the
- * last main commit before the finish.
+ * that had closed by then (a topic's sub-issues plus those since re-parented
+ * into Review issues, or a review's sub-issues in solve order — see
+ * topics.ts), grouped as closed on the finish day (ET) and closed earlier,
+ * each with its set, difficulty, and the solution files as they stood in the
+ * tagged commit — the last main commit before the finish. Problems still open
+ * at the finish are left out: the release records what finished, and an open
+ * optional problem is tracked by its issue (or its Review day), not here.
+ * apps/docs/lib/releases.ts reads these `### Closed …` tables back for the
+ * docs `/changelog` timeline, so their row shape is its contract.
  *
  * The tag is annotated and backdated (tagger date = finish), so
  * `git tag --sort=taggerdate` reads as the campaign's history even for tags
  * minted by a backfill. The release's own published date cannot be backdated
  * (the API has no field for it), so the docs changelog dates each entry from
- * this timever tag instead (`releasesDatedByTag` in apps/docs/blume.config.ts)
+ * this timever tag instead (apps/docs/lib/releases.ts)
  * — the tag format is that contract.
  *
  * Reconciles instead of reacting: every finished topic or review without a
@@ -201,11 +205,11 @@ function bodySection(body: string, heading: string): string | undefined {
 function render(f: Finished, tag: string, sha: string, files: Map<number, string[]>): string {
   const { issue, problems } = f;
   const finishDay = etDate(new Date(f.finishedAt));
-  // Snapshot at the finish instant: a problem closed later was open then.
+  // Snapshot at the finish instant: a problem closed later was open then, and
+  // open problems are not part of the release.
   const closedBy = (p: Problem) => p.closedAt !== null && p.closedAt <= f.finishedAt;
   const onDay = problems.filter((p) => closedBy(p) && etDate(new Date(p.closedAt!)) === finishDay);
   const earlier = problems.filter((p) => closedBy(p) && etDate(new Date(p.closedAt!)) !== finishDay);
-  const open = problems.filter((p) => !closedBy(p));
 
   const row = (p: Problem): string[] => {
     const lc = Number(p.title.match(/^LC (\d+)/)?.[1]);
@@ -248,7 +252,6 @@ function render(f: Finished, tag: string, sha: string, files: Map<number, string
   const sections = [`<!-- release-topics: #${issue.number} -->\n${summary}`, fields.join(" · ")];
   sections.push(`### Closed ${ET_DAY.format(new Date(f.finishedAt))} — the day the ${f.kind} finished\n\n${table(onDay)}`);
   if (earlier.length) sections.push(`### Closed earlier\n\n${table(earlier)}`);
-  if (open.length) sections.push(`### Open at release\n\n${table(open)}`);
   const notes = NOTES.flatMap((h) => {
     const text = bodySection(issue.body, h);
     return text ? [`**${h}.** ${text}`] : [];
diff --git a/apps/cli/sync.ts b/apps/cli/sync.ts
index 31a0878..99f01be 100755
--- a/apps/cli/sync.ts
+++ b/apps/cli/sync.ts
@@ -18,18 +18,25 @@
  *   renders no badges: the docs MDX `wrapper`
  *   (`apps/docs/components/ProblemBadges.astro`) turns `topics:` and the
  *   `video:` key `videos.ts` writes into the badge row under the description.
+ * - Every page carries its GitHub problem issue as frontmatter `issue:` (the
+ *   issue's URL; the `problem`-labelled issue titled `LC <num> · …`), rendered
+ *   by the same wrapper as a GitHub badge after the others. Like `topics:` it
+ *   is filled once — on create, or on any run that finds it missing — and the
+ *   issue list is fetched only on such a run (never on a sync with nothing
+ *   new); offline, or with no `gh` auth, the page is written without it and
+ *   the next sync retries. Delete the key to refetch it.
  * - Every tag a page carries that no campaign topic teaches (not a key of
- *   `apps/docs/topic-landings.ts`) gets a placeholder guide page,
- *   `guides/<slug>.mdx`, with `list:` pointing at LeetCode's problem list for
- *   the tag. Created once (a missing or empty file), then hand-owned except
- *   for `sidebar.badge`, which sync keeps at the guide's backlink count (the
- *   problem pages carrying the tag; dropped at zero); the tag's badge on a
- *   problem page links to it. A guide may be filed into a category `(group)`
- *   folder (e.g. `guides/(2-algorithms)/`) — no route segment, so
- *   `/guides/<slug>` holds — and is found there by slug; a new placeholder
- *   lands at the `guides/` root for a human to file (and give an `icon:`,
- *   which every badge linking to the guide shows; sync warns while one is
- *   missing or shared).
+ *   `apps/docs/topic-landings.ts`) gets a placeholder guide page in the
+ *   Appendix, `appendix/<slug>.mdx`, with `list:` pointing at LeetCode's
+ *   problem list for the tag. Created once (a missing or empty file), then
+ *   hand-owned except for `sidebar.badge`, which sync keeps at the guide's
+ *   backlink count (the problem pages carrying the tag; dropped at zero); the
+ *   tag's badge on a problem page links to it. A guide may be filed into a
+ *   category `(group)` folder (e.g. `appendix/(2-algorithms)/`) — no route
+ *   segment, so `/appendix/<slug>` holds — and is found there by slug; a new
+ *   placeholder lands at the `appendix/` root for a human to file (and give
+ *   an `icon:`, which every badge linking to the guide shows; sync warns
+ *   while one is missing or shared).
  *
  * The sidebar group is the campaign TOPIC from the README table (`tree-dfs/`,
  * ordered by topic number via a script-owned `meta.ts`). A problem outside the
@@ -60,6 +67,7 @@ import { mkdir, readdir, rename, rmdir, unlink } from "node:fs/promises";
 import { basename, dirname, join } from "node:path";
 
 import { TOPIC_LANDINGS } from "../docs/topic-landings.ts";
+import { github } from "./github.ts";
 
 const ROOT = join(import.meta.dir, "..", "..");
 const WORK = join(ROOT, "work", "1");
@@ -397,10 +405,49 @@ function frontmatterTopics(page: string): TopicTag[] {
   return data.topics.filter((t): t is TopicTag => typeof t?.name === "string" && typeof t?.slug === "string");
 }
 
+// ── GitHub problem issues ────────────────────────────────────────
+
+let issueUrls: Promise<Map<number, string> | undefined> | undefined;
+
+/**
+ * LC number → the URL of its `problem` issue (`LC <num> · <Name>`, open or
+ * closed), listed once per run and only when a page first needs it — or
+ * undefined, warned, when GitHub cannot answer (offline commit, no `gh`
+ * auth): pages go without `issue:` and the next sync fills it in.
+ */
+function problemIssues(): Promise<Map<number, string> | undefined> {
+  issueUrls ??= (async () => {
+    try {
+      const gh = await github();
+      const urls = new Map<number, string>();
+      for await (const raw of gh.list(`/repos/${gh.repo}/issues?labels=problem&state=all`)) {
+        if (!raw || typeof raw !== "object" || "pull_request" in raw) continue;
+        if (!("title" in raw) || typeof raw.title !== "string") continue;
+        if (!("html_url" in raw) || typeof raw.html_url !== "string") continue;
+        const lc = raw.title.match(/^LC (\d+) · /)?.[1];
+        if (lc && !urls.has(Number(lc))) urls.set(Number(lc), raw.html_url);
+      }
+      return urls;
+    } catch (err) {
+      console.warn(`no problem issues: ${err instanceof Error ? err.message : err}`);
+      return undefined;
+    }
+  })();
+  return issueUrls;
+}
+
+/** The problem's issue URL, or undefined (warned when GitHub answered but has no such issue). */
+async function issueUrl(sol: Solution): Promise<string | undefined> {
+  const urls = await problemIssues();
+  const url = urls?.get(sol.num);
+  if (urls && !url) console.warn(`no problem issue titled "LC ${sol.num} · …" for ${sol.num}.${sol.slug}`);
+  return url;
+}
+
 // ── guides ───────────────────────────────────────────────────────
 
 /**
- * Placeholder for a tag no campaign topic teaches: the `/guides/<slug>` page a
+ * Placeholder for a tag no campaign topic teaches: the `/appendix/<slug>` page a
  * problem's topic badge links to. `list:` is the tag's LeetCode problem list,
  * rendered as a badge by the docs MDX `wrapper`. Written once — the page
  * is hand-owned from then on.
@@ -419,8 +466,12 @@ function guidePage(tag: TopicTag): string {
   ].join("\n");
 }
 
-/** Folder meta for `guides/`: its own header tab (`navigation.tabs` in blume.config.ts), so only the label. */
-const GUIDES_META = `import { defineMeta } from "blume";\n\nexport default defineMeta({ title: "Guides" });\n`;
+/**
+ * Folder meta for `appendix/`: a drill-in (`display: "page"`) sidebar row
+ * sorted ahead of the phase groups, so it sits right under the root pages
+ * (Introduction, Keywords, Progress).
+ */
+const APPENDIX_META = `import { defineMeta } from "blume";\n\nexport default defineMeta({ title: "Appendix", icon: "library", order: 0, display: "page" });\n`;
 
 /**
  * A guide's frontmatter with `sidebar.badge` set to its backlink count — the
@@ -547,7 +598,7 @@ function warningText(h: Header): string {
 /** Sidebar/page icon for every problem page (Lucide, resolved by Blume). */
 const PAGE_ICON = "dot";
 
-function renderPage(sol: Solution, tags: TopicTag[] | undefined): string {
+function renderPage(sol: Solution, tags: TopicTag[] | undefined, issue: string | undefined): string {
   const h = sol.header;
   const ids = identifiers(sol);
   const description = h.statement[0]?.replace(/\.\s*$/, "") ?? "";
@@ -559,6 +610,7 @@ function renderPage(sol: Solution, tags: TopicTag[] | undefined): string {
     /[:#]/.test(description) ? `description: '${description.replaceAll("'", "''")}'` : `description: ${description}`,
     `icon: ${PAGE_ICON}`,
     ...(tags ? [topicsYaml(tags)] : []),
+    ...(issue ? [`issue: ${JSON.stringify(issue)}`] : []),
     "sidebar:",
     `  label: '${h.title.replaceAll("'", "''")}'`,
     `  badge: '${h.difficulty}'`,
@@ -654,6 +706,15 @@ async function ensureTopics(page: string, sol: Solution): Promise<string> {
   return fm[0].replace(/^sidebar:$/m, `${topicsYaml(tags)}\nsidebar:`) + page.slice(fm[0].length);
 }
 
+/** Insert `issue:` before `sidebar:` when the frontmatter lacks it; an existing URL is kept as is. */
+async function ensureIssue(page: string, sol: Solution): Promise<string> {
+  const fm = page.match(/^---\n[\s\S]*?\n---/);
+  if (!fm || /^issue:/m.test(fm[0])) return page;
+  const url = await issueUrl(sol);
+  if (!url) return page;
+  return fm[0].replace(/^sidebar:$/m, `issue: ${JSON.stringify(url)}\nsidebar:`) + page.slice(fm[0].length);
+}
+
 /**
  * Offset just past the script-owned `## Solution` section: the next top-level
  * heading that is not inside a code fence, or end of file. Sections a human
@@ -713,7 +774,7 @@ for (const sol of ordered) {
     }
     const tail = page.slice(solutionEnd(page, at));
     const body = page.slice(0, at) + solutionSection(sol) + (tail ? `\n${tail}` : "");
-    const next = await ensureTopics(ensureIcon(ensureLabel(body, sol.header)), sol);
+    const next = await ensureIssue(await ensureTopics(ensureIcon(ensureLabel(body, sol.header)), sol), sol);
     const actions: string[] = [];
     if (existing !== name) {
       await rename(join(DOCS, existing), join(DOCS, name));
@@ -727,7 +788,7 @@ for (const sol of ordered) {
     report.push([workRef, name, actions.join(" + ") || "skipped (in sync)"]);
     written = next;
   } else {
-    const page = renderPage(sol, await fetchTopicTags(sol));
+    const page = renderPage(sol, await fetchTopicTags(sol), await issueUrl(sol));
     await Bun.write(join(DOCS, name), page);
     report.push([workRef, name, "created"]);
     written = page;
@@ -758,16 +819,16 @@ for (const sol of ordered) {
 
 // One guide page per tag that no campaign topic teaches, created when missing
 // (an empty file counts as missing) and never rewritten. A guide is found by
-// slug anywhere under guides/ — a human files it into a category `(group)`,
-// which leaves its route alone — and a new one lands at the guides/ root. A
+// slug anywhere under appendix/ — a human files it into a category `(group)`,
+// which leaves its route alone — and a new one lands at the appendix/ root. A
 // guide whose tag no page carries any more is left alone: it is hand-owned.
 const guideTags = [...tags.values()]
   .filter((tag) => !TOPIC_LANDINGS[tag.slug])
   .sort((a, b) => a.slug.localeCompare(b.slug));
 const guideFiles = new Map<string, string>(); // slug -> path relative to DOCS
-for await (const rel of new Bun.Glob("guides/**/*.mdx").scan(DOCS)) guideFiles.set(basename(rel, ".mdx"), rel);
+for await (const rel of new Bun.Glob("appendix/**/*.mdx").scan(DOCS)) guideFiles.set(basename(rel, ".mdx"), rel);
 for (const tag of guideTags) {
-  const rel = guideFiles.get(tag.slug) ?? `guides/${tag.slug}.mdx`;
+  const rel = guideFiles.get(tag.slug) ?? `appendix/${tag.slug}.mdx`;
   const file = Bun.file(join(DOCS, rel));
   if ((await file.exists()) && file.size > 0) continue;
   await Bun.write(file, guidePage(tag));
@@ -785,7 +846,7 @@ for (const tag of guideTags) {
 // and must not be another guide's.
 const topicIcons = new Set(Object.values(TOPIC_ICONS));
 const guideIcons = new Map<string, string>(); // icon -> the guide that took it first
-for await (const rel of new Bun.Glob("guides/**/*.mdx").scan(DOCS)) {
+for await (const rel of new Bun.Glob("appendix/**/*.mdx").scan(DOCS)) {
   const slug = basename(rel, ".mdx");
   const count = TOPIC_LANDINGS[slug] ? 0 : (tagged.get(slug) ?? 0);
   const page = await Bun.file(join(DOCS, rel)).text();
@@ -809,11 +870,11 @@ for (const [dir, phase] of phases) {
   report.push([`phase ${phase.order}`, `${dir}/meta.ts`, "created"]);
 }
 
-// Script-owned folder metas — one per live topic folder, plus guides/ —
+// Script-owned folder metas — one per live topic folder, plus appendix/ —
 // rewritten only when they differ.
 const metas: [label: string, dir: string, meta: string][] = [
   ...[...groups].map(([dir, topic]): [string, string, string] => [`topic ${topic.order ?? "-"}`, dir, groupMeta(topic)]),
-  ...(guideTags.length ? [["guides", "guides", GUIDES_META] as [string, string, string]] : []),
+  ...(guideTags.length ? [["appendix", "appendix", APPENDIX_META] as [string, string, string]] : []),
 ];
 for (const [label, dir, meta] of metas) {
   const path = join(DOCS, dir, "meta.ts");