diff --git a/.github/scripts/announce-discord.mjs b/.github/scripts/announce-discord.mjs
index 06d933c..77b150d 100644
--- a/.github/scripts/announce-discord.mjs
+++ b/.github/scripts/announce-discord.mjs
@@ -1,20 +1,25 @@
 #!/usr/bin/env node
-// Post a release announcement to a Discord webhook. Formats mechanically from
-// the GitHub Release: title + the opening sentence(s) of the lead paragraph
-// (the code-dense detail comes later, so the opener reads cleanly) + link.
-// Transport-agnostic formatting lives here so it can move into a shared action
-// verbatim when we extend to nimblebrain / mpak.
+// Post a synapse release announcement to the NimbleBrain #announcements Discord
+// webhook. Formats from the GitHub Release: a one-sentence teaser (synapse's
+// CHANGELOG leads are code-dense, so the opening sentence reads far cleaner in
+// Discord than the full body) plus links to the full notes and the compare diff.
+//
+// Synapse-specific by design — NOT a shared/reusable action. Other products get
+// their own announce, tuned to their own changelog style.
 //
 // Env:
-//   WEBHOOK_URL   Discord webhook. Empty/unset -> print payload + skip (never
-//                 fails a release, so merging before the secret exists is safe).
+//   WEBHOOK_URL   Discord webhook. Empty/unset -> print payload + skip (a release
+//                 never fails on a missing secret).
 //   REPO          owner/name (GITHUB_REPOSITORY).
-//   RELEASE_JSON  path to `gh release view ... --json tagName,name,body,url`.
+//   RELEASE_JSON  path to `gh release view ... --json tagName,name,body,url,publishedAt`.
+//   PREV_TAG      previous release tag, for the compare link (optional).
 //   DRY_RUN       "true" -> print payload, don't POST.
 import { readFileSync } from "node:fs";
 
 const webhook = (process.env.WEBHOOK_URL || "").trim();
-const repoName = (process.env.REPO || "").split("/").pop() || "release";
+const repo = process.env.REPO || "NimbleBrainInc/synapse";
+const repoName = repo.split("/").pop() || "synapse";
+const prevTag = (process.env.PREV_TAG || "").trim();
 const dryRun = process.env.DRY_RUN === "true";
 
 const rel = JSON.parse(readFileSync(process.env.RELEASE_JSON || "release.json", "utf8"));
@@ -34,11 +39,9 @@ for (; i < lines.length; i++) {
 }
 const para = lead.join(" ").trim();
 
-// Teaser = the first sentence (plus the second only if the first is terse and
-// they still fit). CHANGELOG leads open with prose; the inline-code-heavy detail
-// comes later, so an opening sentence renders cleanly in Discord instead of a
-// wall of code pills. Sentence boundaries are detected backtick-aware, so a `.`
-// inside an identifier like `tokens.bgSubtle` is never a false split.
+// Teaser = the first sentence (+ the second only if the first is terse and they
+// still fit). Sentence boundaries are detected backtick-aware, so a `.` inside an
+// identifier like `tokens.bgSubtle` is never a false split.
 function splitSentences(text) {
   let inCode = false;
   let start = 0;
@@ -72,17 +75,27 @@ if (desc.length > CAP) {
   desc = `${desc.slice(0, cut > 0 ? cut : CAP).trimEnd()}…`;
 }
 if (!desc) {
-  // The parser found no prose lead under the version heading (e.g. a CHANGELOG
-  // that leads with `### Fixed`, or a manually-cut release using GitHub's
-  // auto-generated notes). Post a generic line but make the gap visible in the
-  // run log rather than silently shipping content-free copy.
-  console.log("::warning::No lead paragraph found in the release body — posting generic copy. Check the CHANGELOG format.");
+  console.log("::warning::No lead paragraph found in the release body — posting generic copy. Check CHANGELOG.md.");
+}
+
+const links = [`[Full release notes →](${url})`];
+if (prevTag && tag) {
+  links.push(`[Changelog ${prevTag}…${tag} →](https://github.com/${repo}/compare/${prevTag}...${tag})`);
 }
-const description = `${desc || "New release."}\n\n[Full release notes →](${url})`;
+const description = `${desc || "New release."}\n\n${links.join("\n")}`;
 
 const payload = {
   username: "NimbleBrain Releases",
-  embeds: [{ title: `🚀 ${repoName} ${tag}`, url, description, color: 0x0055ff }],
+  embeds: [
+    {
+      title: `🚀 ${repoName} ${tag}`,
+      url,
+      description,
+      color: 0x0055ff, // NimbleBrain brand blue
+      footer: { text: "@nimblebrain/synapse" },
+      ...(rel.publishedAt ? { timestamp: rel.publishedAt } : {}),
+    },
+  ],
 };
 
 if (!webhook || dryRun) {
diff --git a/.github/workflows/announce.yml b/.github/workflows/announce.yml
index f7218bb..8098b30 100644
--- a/.github/workflows/announce.yml
+++ b/.github/workflows/announce.yml
@@ -41,12 +41,22 @@ jobs:
           TAG: ${{ github.event.release.tag_name || github.event.inputs.tag }}
         run: |
           gh release view "$TAG" --repo "$GITHUB_REPOSITORY" \
-            --json tagName,name,body,url > release.json
+            --json tagName,name,body,url,publishedAt > release.json
+          # Previous release tag for the compare link: the newest non-current
+          # published release. Assumes single-track sequential releases (true for
+          # synapse — semver order matches publish order). A backport published
+          # after a higher version would yield a cosmetically backwards compare
+          # link; switch the pipe to `sort -V` if synapse ever ships out of order.
+          # Empty on the first release -> the script omits the compare link.
+          PREV=$(gh release list --repo "$GITHUB_REPOSITORY" --exclude-drafts \
+            --json tagName --jq '.[].tagName' | grep -vxF "$TAG" | head -n1 || true)
+          echo "PREV_TAG=$PREV" >> "$GITHUB_ENV"
 
       - name: Announce to Discord
         env:
           WEBHOOK_URL: ${{ secrets.DISCORD_ANNOUNCE_WEBHOOK }}
           REPO: ${{ github.repository }}
           RELEASE_JSON: release.json
+          PREV_TAG: ${{ env.PREV_TAG }}
           DRY_RUN: ${{ github.event.inputs.dry_run || 'false' }}
         run: node .github/scripts/announce-discord.mjs