diff --git a/server/__tests__/update-check-plugin-nogit.test.js b/server/__tests__/update-check-plugin-nogit.test.js
index 091e8dd7..4fe1a4c5 100644
--- a/server/__tests__/update-check-plugin-nogit.test.js
+++ b/server/__tests__/update-check-plugin-nogit.test.js
@@ -176,8 +176,15 @@ describe("getUpdatesStatus — plugin cache with no .git", () => {
 
     const s = await getUpdatesStatus(root, { latestRelease: release("v1.5.1") });
 
-    // The old behaviour: message set, everything else absent.
-    assert.equal(s.message, null, "must not fall through to the not-a-git-clone payload");
+    // The old behaviour: the not-a-git-clone message, everything else absent.
+    // Asserted on the message's CONTENT, not on it being null — a plugin
+    // install now carries its own sentence, and null was only ever a proxy for
+    // "did not fall through here".
+    assert.doesNotMatch(
+      s.message,
+      /not a git clone/i,
+      "must not fall through to the not-a-git-clone payload"
+    );
     assert.equal(s.release_check, "ok", "the release layer must actually run");
     assert.equal(s.install_kind, "plugin");
     assert.equal(s.plugin_marketplace, "sg");
@@ -208,6 +215,31 @@ describe("getUpdatesStatus — plugin cache with no .git", () => {
     assert.ok(s.plugin_marketplace && s.plugin_name && s.repo_root);
   });
 
+  it("carries a human-readable message in every outcome, never a null", async () => {
+    // `agenthub update-check` prints `message` as its headline. Null here made
+    // it print the literal "null" on every plugin-cache install — the one kind
+    // that has no commit count to fall back on.
+    const cases = [
+      [makePluginInstall("msg-newer").root, { latestRelease: release("v1.6.0") }, /v1\.6\.0/],
+      [makePluginInstall("msg-current").root, { latestRelease: release("v1.5.0") }, /newest/i],
+      [
+        makePluginInstall("msg-failed").root,
+        { latestRelease: { ok: false, reason: "unreachable" } },
+        /unreachable/,
+      ],
+      [
+        makePluginInstall("msg-noversion", { version: null }).root,
+        { latestRelease: release("v1.6.0") },
+        /no version|cannot be compared/i,
+      ],
+    ];
+    for (const [root, opts, expected] of cases) {
+      const s = await getUpdatesStatus(root, opts);
+      assert.equal(typeof s.message, "string", `message must be a string, got ${s.message}`);
+      assert.match(s.message, expected);
+    }
+  });
+
   it("does not treat an older published release as an update", async () => {
     const { root } = makePluginInstall("older");
     const s = await getUpdatesStatus(root, { latestRelease: release("v1.4.0") });
diff --git a/server/lib/update-check.js b/server/lib/update-check.js
index 5ea04702..10c5287d 100644
--- a/server/lib/update-check.js
+++ b/server/lib/update-check.js
@@ -402,7 +402,17 @@ async function pluginStatus(root, pluginInstall, options = {}) {
       `commands — "Update now" runs them for you and restarts the dashboard. An already-open ` +
       `Claude Code session still needs '/reload-plugins' to pick up new skills and commands.`,
     manual_command: manualParts.join(" && "),
-    message: null,
+    // A plugin install compares versions exactly like a checkout does, so it
+    // gets the same sentence. Left null, `agenthub update-check` printed the
+    // literal "null" as its headline on every plugin-cache install — the one
+    // install kind that cannot fall back to a commit count.
+    message: releaseIsNewer
+      ? `Release ${release.tag} is available (this install reports ${localVersion || "no version"}).`
+      : comparable
+        ? `Running the newest release (${release.tag}).`
+        : release.ok
+          ? `This install reports no version, so it cannot be compared with release ${release.tag}.`
+          : `Could not read the latest release (${release.reason}); version comparison unavailable.`,
 
     install_kind: "plugin",
     plugin_marketplace: pluginInstall.marketplace,