diff --git a/workers/godlock-uk/package.json b/workers/godlock-uk/package.json
index 9bc3b89..626514f 100644
--- a/workers/godlock-uk/package.json
+++ b/workers/godlock-uk/package.json
@@ -5,7 +5,7 @@
   "license": "Apache-2.0",
   "type": "module",
   "scripts": {
-    "test": "node --test steer.test.mjs presence.test.mjs pages.test.mjs engine.test.mjs runtime.test.mjs mesh.test.mjs site-presence.test.mjs donate.test.mjs receipts.test.mjs identity.test.mjs ingest.test.mjs shelves.test.mjs redline.test.mjs submit.test.mjs survival.test.mjs help.test.mjs softwares-ssot.test.mjs sot-outlet.test.mjs debate-score.test.mjs indexnow.test.mjs"
+    "test": "node --test steer.test.mjs presence.test.mjs pages.test.mjs engine.test.mjs runtime.test.mjs mesh.test.mjs site-presence.test.mjs donate.test.mjs receipts.test.mjs identity.test.mjs ingest.test.mjs shelves.test.mjs redline.test.mjs submit.test.mjs survival.test.mjs help.test.mjs softwares-ssot.test.mjs sot-outlet.test.mjs debate-score.test.mjs indexnow.test.mjs thread-expand.test.mjs"
   },
   "dependencies": {
     "wrangler": "^4.127.1"
diff --git a/workers/godlock-uk/src/index.js b/workers/godlock-uk/src/index.js
index d5a8191..d89d527 100644
--- a/workers/godlock-uk/src/index.js
+++ b/workers/godlock-uk/src/index.js
@@ -23,6 +23,7 @@ import {
 import { donateDoc, DONATE_RAILS, donateQrIdFromPath } from "./donate.js";
 import { handleRuntimeRoot, isRuntimeRequest, runtimeCors } from "./runtimeRoot.js";
 import { appendLedger, verifyLedger, ledgerEntriesForId, sha256hex } from "./ledger.js";
+import { receiptProofForId } from "./receiptProof.js";
 import {
   robotsTxt, sitemapXml, citeDoc, llmsDoc, aiDoc, siteOpenApi, mcpDiscoveryDoc, BANNER, DOWNLOAD, DOWNLOAD_STATS, DOWNLOAD_COUNT, GITHUB, AUTHOR,
   indexNowKeyBody, INDEXNOW_KEY_PATH, INDEXNOW_WELL_KNOWN_PATH,
@@ -1276,10 +1277,12 @@ export default {
         const entries = await ledgerEntriesForId(env, id);
         const stats = await gatherStats(env, { wrote, ctx });
         if (wantsJson(request, url)) {
+          const proof = await receiptProofForId(env, id);
           return json({
             ok: true,
             receipt: publicPayload(row),
             ledger: entries,
+            proof,
             current_score: stats.current_score,
             residual: stats.residual,
             triad_display: stats.triad_display,
diff --git a/workers/godlock-uk/src/receiptProof.js b/workers/godlock-uk/src/receiptProof.js
new file mode 100644
index 0000000..5dec3d6
--- /dev/null
+++ b/workers/godlock-uk/src/receiptProof.js
@@ -0,0 +1,91 @@
+/**
+ * Receipt proof for the expand (drop-down) view of a public thread.
+ * Hash-linked and sealed. NOT signed: there is no signature anywhere here.
+ *
+ * Fails closed: status is "verified" only when every ledger entry for the
+ * receipt recomputes to its entry_hash, links to the entry before it, and the
+ * whole ledger verifies from genesis to the head that is reported as the seal.
+ * Anything else is "unverified" or "missing". Nothing is invented.
+ * Author: Aziel Eliab.
+ */
+import { hashPayload, ZERO } from "./ledger.js";
+
+export const PROOF_NOT_SIGNED = "Hash-linked and sealed. Not signed.";
+
+function parse(blob) {
+  try { return { ok: true, value: JSON.parse(blob || "{}") }; } catch { return { ok: false, value: {} }; }
+}
+
+/**
+ * Pure. rows = every ledger row (sequence ASC, raw payload_json), id = receipt id.
+ * Returns { status, receipt_hash, prev_hash, seal, sealed_at, entries, errors, not_signed }.
+ */
+export function buildReceiptProof(rows, id) {
+  const needle = String(id || "");
+  const all = Array.isArray(rows) ? rows : [];
+  const errors = [];
+  let expectedPrev = ZERO;
+  let expectedSeq = 1;
+  let head = ZERO;
+  let headAt = null;
+  const mine = [];
+  for (const row of all) {
+    const seq = Number(row.sequence);
+    if (seq !== expectedSeq) errors.push("sequence gap at " + seq);
+    if (String(row.previous_hash) !== expectedPrev) errors.push("previous_hash mismatch at sequence " + seq);
+    const p = parse(row.payload_json);
+    if (!p.ok) errors.push("payload_json not JSON at sequence " + seq);
+    const recomputed = hashPayload({
+      sequence: seq,
+      timestamp_utc: row.timestamp_utc,
+      action: row.action,
+      payload: p.value,
+      previous_hash: row.previous_hash,
+    });
+    const hashOk = p.ok && recomputed === row.entry_hash;
+    if (!hashOk) errors.push("entry_hash mismatch at sequence " + seq);
+    if (needle && String(row.payload_json || "").indexOf(needle) >= 0) {
+      mine.push({
+        sequence: seq,
+        action: String(row.action),
+        timestamp_utc: row.timestamp_utc,
+        entry_hash: String(row.entry_hash),
+        previous_hash: String(row.previous_hash),
+        hash_ok: hashOk,
+        link_ok: String(row.previous_hash) === expectedPrev,
+      });
+    }
+    expectedPrev = String(row.entry_hash);
+    expectedSeq = seq + 1;
+    head = String(row.entry_hash);
+    headAt = row.timestamp_utc;
+  }
+  const base = { not_signed: PROOF_NOT_SIGNED, verify_url: "/verify", entries: mine };
+  if (!mine.length) {
+    return { ...base, status: "missing", receipt_hash: null, prev_hash: null, seal: null, sealed_at: null, errors: ["no ledger entry for this receipt"] };
+  }
+  const first = mine[0];
+  const chainOk = errors.length === 0 && mine.every((e) => e.hash_ok && e.link_ok);
+  return {
+    ...base,
+    status: chainOk ? "verified" : "unverified",
+    receipt_hash: first.entry_hash,
+    prev_hash: first.previous_hash,
+    timestamp_utc: first.timestamp_utc,
+    // The seal is the ledger head the chain verified up to. Only reported when it verified.
+    seal: chainOk ? head : null,
+    sealed_at: chainOk ? headAt : null,
+    errors,
+  };
+}
+
+export async function receiptProofForId(env, id) {
+  try {
+    const rows = (await env.DB.prepare(
+      "SELECT sequence, timestamp_utc, action, payload_json, previous_hash, entry_hash FROM ledger ORDER BY sequence ASC"
+    ).all()).results || [];
+    return buildReceiptProof(rows, id);
+  } catch (err) {
+    return { status: "missing", not_signed: PROOF_NOT_SIGNED, verify_url: "/verify", entries: [], receipt_hash: null, prev_hash: null, seal: null, sealed_at: null, errors: ["ledger read failed"] };
+  }
+}
diff --git a/workers/godlock-uk/src/ui.js b/workers/godlock-uk/src/ui.js
index afd113e..609b006 100644
--- a/workers/godlock-uk/src/ui.js
+++ b/workers/godlock-uk/src/ui.js
@@ -507,13 +507,76 @@ export function priorReceiptItems(rows, { fullChallenge = false } = {}) {
   return (rows || []).map((r) => {
     const challenge = fullChallenge ? challengeBlockText(r) : challengePreview(r);
     return `<li>
-      <div class="challenge-preview">${esc(challenge)}</div>
+      <details class="thread" data-receipt-id="${esc(r.id)}">
+      <summary><span class="challenge-preview">${esc(challenge)}</span></summary>
+      <div class="thread-body" aria-live="polite"><p class="muted">Loading reasoning and receipt…</p></div>
+      </details>
       ${rescoreLine(r)}
       <div class="muted">${esc(when(r.created_utc))}</div>
       <a href="/receipt/${esc(r.id)}">Receipt</a></li>`;
   }).join("");
 }
 
+/**
+ * Pure view model for an expanded thread. Input is the /receipt/:id?format=json
+ * body (or null on fetch failure). Fails closed: only status "verified" from the
+ * server proof is shown as verified. Never invents reasoning or a receipt.
+ * Kept free of outer references so it can be inlined via toString().
+ */
+export function threadView(j) {
+  var out = { reasoning: [], receipt: [], status: "missing", note: "Hash-linked and sealed. Not signed." };
+  if (!j || j.ok !== true || !j.receipt) {
+    out.receipt.push(["Receipt", "missing (could not be fetched)"]);
+    return out;
+  }
+  var r = j.receipt;
+  if (typeof r.summary === "string" && r.summary) out.reasoning.push(["Summary", r.summary]);
+  if (typeof r.explanation === "string" && r.explanation) out.reasoning.push(["Reasoning", r.explanation]);
+  if (!out.reasoning.length) out.reasoning.push(["Reasoning", "No reasoning was recorded for this receipt."]);
+  var p = j.proof;
+  if (!p || typeof p !== "object") {
+    out.receipt.push(["Receipt", "missing (no proof returned)"]);
+    return out;
+  }
+  var st = p.status === "verified" ? "verified" : (p.status === "unverified" ? "unverified" : "missing");
+  if (st === "verified" && !(p.receipt_hash && p.prev_hash && p.seal)) st = "unverified";
+  out.status = st;
+  out.receipt.push(["Status", st]);
+  out.receipt.push(["Receipt hash", p.receipt_hash || "missing"]);
+  out.receipt.push(["Prev hash", p.prev_hash || "missing"]);
+  out.receipt.push(["Seal (verified ledger head)", st === "verified" ? p.seal : "missing"]);
+  out.receipt.push(["Timestamp", p.timestamp_utc || "missing"]);
+  out.receipt.push(["Verify", p.verify_url || "/verify"]);
+  return out;
+}
+
+export function threadExpandScript() {
+  return `<script>
+(function(){
+  var threadView=${threadView.toString()};
+  function row(box,k,v,mono){var p=document.createElement("p");var b=document.createElement("b");b.textContent=k+": ";p.appendChild(b);
+    if(k==="Verify"){var a=document.createElement("a");a.href=v;a.textContent="Verify chain";p.appendChild(a);}
+    else{var s=document.createElement("span");s.textContent=String(v);if(mono)s.className="hash";p.appendChild(s);}box.appendChild(p);}
+  function render(body,j){var m=threadView(j);body.textContent="";
+    m.reasoning.forEach(function(x){row(body,x[0],x[1],false);});
+    var h=document.createElement("div");h.className="k";h.textContent="Receipt ("+m.status+")";body.appendChild(h);
+    m.receipt.forEach(function(x){row(body,x[0],x[1],/hash|Seal/.test(x[0]));});
+    var n=document.createElement("p");n.className="muted";n.textContent=m.note;body.appendChild(n);}
+  document.querySelectorAll("details.thread").forEach(function(d){
+    d.addEventListener("toggle",function(){
+      if(!d.open||d.getAttribute("data-loaded"))return;
+      d.setAttribute("data-loaded","1");
+      var body=d.querySelector(".thread-body");
+      fetch("/receipt/"+encodeURIComponent(d.getAttribute("data-receipt-id"))+"?format=json",{headers:{"Accept":"application/json"}})
+        .then(function(r){return r.ok?r.json():null;})
+        .then(function(j){render(body,j);})
+        .catch(function(){render(body,null);});
+    });
+  });
+})();
+</script>`;
+}
+
 export function nodesLiveFromStats(stats) {
   const s = stats && typeof stats === "object" ? stats : {};
   const mesh = s.mesh && typeof s.mesh === "object" ? s.mesh : {};
@@ -641,6 +704,7 @@ ${latestHtml}
 <h2>Prior receipts</h2>
 <p class="muted prior-more">Newest ${esc(HOME_PRIOR_LIMIT)}. Every receipt is kept. <a href="${esc(RECEIPTS_PATH)}">Full receipts chain</a>.</p>
 <ul class="prior">${list}</ul>
+${threadExpandScript()}
 `;
 }
 
@@ -677,6 +741,7 @@ ${steerPanel(s.steer, s)}
 <p class="muted"><a href="${esc(REASON_PATH)}">How it is scored</a> · <a href="/">Ask a question</a>.</p>
 ${receiptsPager({ page, pages, total: total != null ? total : receipts })}
 <ul class="prior">${list}</ul>
+${threadExpandScript()}
 ${ingestTipSection()}
 ${actReceiptsSection(rows)}
 `;
diff --git a/workers/godlock-uk/thread-expand.test.mjs b/workers/godlock-uk/thread-expand.test.mjs
new file mode 100644
index 0000000..b0ccde2
--- /dev/null
+++ b/workers/godlock-uk/thread-expand.test.mjs
@@ -0,0 +1,71 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { hashPayload, canonicalJson, ZERO } from "./src/ledger.js";
+import { buildReceiptProof } from "./src/receiptProof.js";
+import { threadView, threadExpandScript, priorReceiptItems } from "./src/ui.js";
+
+function chain(payloads) {
+  const rows = []; let prev = ZERO;
+  payloads.forEach((payload, i) => {
+    const e = { sequence: i + 1, timestamp_utc: "2026-10-0" + (i + 1) + "T00:00:00.000Z", action: "submit", payload, previous_hash: prev };
+    const entry_hash = hashPayload(e);
+    rows.push({ ...e, payload_json: canonicalJson(payload), entry_hash });
+    prev = entry_hash;
+  });
+  return rows;
+}
+
+describe("receipt proof", () => {
+  const rows = chain([{ id: "aaa" }, { id: "bbb111" }, { id: "ccc" }]);
+  it("verifies and seals at the ledger head", () => {
+    const p = buildReceiptProof(rows, "bbb111");
+    assert.equal(p.status, "verified");
+    assert.equal(p.receipt_hash, rows[1].entry_hash);
+    assert.equal(p.prev_hash, rows[0].entry_hash);
+    assert.equal(p.seal, rows[2].entry_hash);
+    assert.match(p.not_signed, /Not signed/);
+  });
+  it("missing receipt fails closed", () => {
+    const p = buildReceiptProof(rows, "zzz999");
+    assert.equal(p.status, "missing"); assert.equal(p.seal, null);
+  });
+  it("tampered payload is unverified with no seal", () => {
+    const bad = rows.map((r) => ({ ...r }));
+    bad[1].payload_json = canonicalJson({ id: "bbb111", x: 1 });
+    const p = buildReceiptProof(bad, "bbb111");
+    assert.equal(p.status, "unverified"); assert.equal(p.seal, null);
+  });
+  it("tamper elsewhere in the chain also blocks the seal", () => {
+    const bad = rows.map((r) => ({ ...r })); bad[2].previous_hash = ZERO;
+    assert.equal(buildReceiptProof(bad, "bbb111").status, "unverified");
+  });
+});
+
+describe("thread expand view", () => {
+  it("fetch failure shows receipt missing, no reasoning invented", () => {
+    const v = threadView(null);
+    assert.equal(v.status, "missing"); assert.equal(v.reasoning.length, 0);
+  });
+  it("verified proof renders hashes, seal and verify link", () => {
+    const v = threadView({ ok: true, receipt: { summary: "S", explanation: "E" }, proof: { status: "verified", receipt_hash: "h1", prev_hash: "h0", seal: "h9", timestamp_utc: "t", verify_url: "/verify" } });
+    assert.equal(v.status, "verified");
+    assert.deepEqual(v.reasoning, [["Summary", "S"], ["Reasoning", "E"]]);
+    const m = Object.fromEntries(v.receipt);
+    assert.equal(m["Seal (verified ledger head)"], "h9"); assert.equal(m.Verify, "/verify");
+  });
+  it("verified without a seal is downgraded", () => {
+    const v = threadView({ ok: true, receipt: { summary: "S" }, proof: { status: "verified", receipt_hash: "h1", prev_hash: "h0", seal: null } });
+    assert.equal(v.status, "unverified");
+  });
+  it("unverified proof never shows a seal", () => {
+    const v = threadView({ ok: true, receipt: {}, proof: { status: "unverified", receipt_hash: "h1", prev_hash: "h0", seal: "h9" } });
+    assert.equal(Object.fromEntries(v.receipt)["Seal (verified ledger head)"], "missing");
+  });
+  it("prior rows render a drop-down and the page script parses", () => {
+    const html = priorReceiptItems([{ id: "abc", created_utc: "2026-10-01T00:00:00Z", challenge_text: "q" }]);
+    assert.match(html, /<details class="thread" data-receipt-id="abc">/);
+    const js = threadExpandScript().replace(/^<script>|<\/script>$/g, "");
+    assert.doesNotThrow(() => new Function(js));
+    assert.doesNotMatch(threadExpandScript(), /signed by|signature/i);
+  });
+});