diff --git a/‎.changeset/22071-runtime-assets-boot-warning.md‎
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Lines changed: 13 additions & 0 deletions
diff --git a/‎packages/cli/src/commands/serve.ts‎
Lines changed: 10 additions & 6 deletions b/‎packages/cli/src/commands/serve.ts‎
Lines changed: 10 additions & 6 deletions
diff --git a/‎packages/cli/src/utils/console.ts‎
Lines changed: 179 additions & 7 deletions b/‎packages/cli/src/utils/console.ts‎
Lines changed: 179 additions & 7 deletions
@@ -0,0 +1,13 @@
+---
+"@objectstack/cli": patch
+---
+
+`os serve` (and `objectstack start`, which runs it) now says at boot when an app's branding logo or favicon will not be served. Before, the runtime assets route was skipped without a word when its directory was absent, so an artifact booted outside its project directory drew a broken logo and favicon and nothing in the boot output said why.
+
+Clause-②: no
+
+- Once the boot settles, every loaded app whose `branding.logo` or `branding.favicon` is a root path under `/runtime/assets/` that the route will not serve gets one warning line per file. The line names the apps and keys that use the file, the directory searched, and whether that directory came from `OS_RUNTIME_ASSETS_DIR` or the `assets/` default under the working directory. When the directory does not exist, the line says so and says nothing under `/runtime/assets/` is mounted for this run.
+- The apps read are the ones the console is served, through the same metadata protocol read that `GET /api/v1/meta/app` answers from. Config boots and artifact boots are both covered.
+- Whether a file is servable is decided by the route's own filename resolution, so the warning and the route cannot disagree. Absolute URLs, protocol-relative URLs, data URIs, relative paths and other root paths are not checked.
+- The line goes through the kernel logger at `warn`. It shows in the banner's *Boot diagnostics* block, streams live at `--log-level debug` or `info`, and is hidden at `error` or `silent` like every other boot warning.
+- ⛔ What `/runtime/assets/*` serves does not change. No route is added or removed, and the artifact still carries no asset files: ship the `assets/` directory beside it, or point `OS_RUNTIME_ASSETS_DIR` at the files.
@@ -3715,12 +3715,16 @@ export default class Serve extends Command {
       // dist hasn't been built yet.  The directory is resolved as:
       //   1. OS_RUNTIME_ASSETS_DIR env var (explicit override)
       //   2. process.cwd() + '/assets' (when CLI cwd is a runtime/ package)
-      // Silently skips if no assets directory exists.
-      const runtimeAssetsDir = (
-        process.env.OS_RUNTIME_ASSETS_DIR?.trim() ||
-        path.resolve(process.cwd(), 'assets')
-      );
-      await kernel.use(createRuntimeAssetsPlugin(runtimeAssetsDir));
+      // No route is mounted when the directory does not exist. That is not
+      // silent (#22071): once the boot settles, the plugin warns for every
+      // loaded app's branding logo / favicon under /runtime/assets/ it will not
+      // serve, naming the directory searched and which of the two it came from.
+      const runtimeAssetsDirFromEnv = process.env.OS_RUNTIME_ASSETS_DIR?.trim();
+      const runtimeAssetsDir = runtimeAssetsDirFromEnv || path.resolve(process.cwd(), 'assets');
+      await kernel.use(createRuntimeAssetsPlugin(
+        runtimeAssetsDir,
+        runtimeAssetsDirFromEnv ? 'OS_RUNTIME_ASSETS_DIR' : 'cwd',
+      ));
 
       // Unknown-environment hostname guard.
       //
 
@@ -591,16 +591,172 @@ export function createConsoleStaticPlugin(distPath: string, options?: { isDev?:
 
 // ─── Runtime Assets Plugin ──────────────────────────────────────────
 
+/** The URL prefix the runtime assets route is mounted under. */
+const RUNTIME_ASSETS_URL_PREFIX = '/runtime/assets/';
+
+/**
+ * Where the host found the directory it handed {@link createRuntimeAssetsPlugin}:
+ * named by `OS_RUNTIME_ASSETS_DIR`, or the `<cwd>/assets` default taken because
+ * that variable is unset. Only the boot warning reads it, to name the remedy.
+ * Not exported: this module's export set is pinned
+ * (`test/published-subpath-console.pin.test.ts`), and the union is spelled out
+ * structurally in the plugin's signature.
+ */
+type RuntimeAssetsDirSource = 'OS_RUNTIME_ASSETS_DIR' | 'cwd';
+
+/**
+ * The ONE resolution of a `/runtime/assets/:filename` parameter to a path on
+ * disk. The route serves through it and the boot check judges through it
+ * (#22071), so the two cannot disagree about which file a name means or which
+ * names are refused. `null` means the name escapes `assetsDir`, which the route
+ * answers 403.
+ */
+function resolveRuntimeAssetPath(assetsDir: string, filename: string): string | null {
+  const filePath = path.join(assetsDir, filename.replace(/[/\\]+/g, ''));
+  // Path-traversal guard: reject any path that escapes assetsDir.
+  if (!path.resolve(filePath).startsWith(path.resolve(assetsDir))) return null;
+  return filePath;
+}
+
+/**
+ * Whether the route answers 200 for this `:filename`: the same resolution, then
+ * what the route's `readFileSync` needs, a readable regular file. A directory,
+ * a missing file and a refused name all answer no.
+ */
+function runtimeAssetIsServable(assetsDir: string, filename: string): boolean {
+  const filePath = resolveRuntimeAssetPath(assetsDir, filename);
+  if (filePath === null) return false;
+  try {
+    if (!fs.statSync(filePath).isFile()) return false;
+    fs.accessSync(filePath, fs.constants.R_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * What a branding URL asks the runtime assets route for, read the way a browser
+ * resolves an `<img src>` on this origin (dot segments, query and fragment
+ * removed). `undefined` when the value is not this route's URL: an absolute or
+ * protocol-relative URL, a data URI, a relative path or any other root path
+ * names something this plugin does not serve, so it is not checked.
+ * `filename: null` is a path below a subdirectory, which the route's single
+ * `:filename` segment never matches.
+ */
+function runtimeAssetRequest(value: unknown): { url: string; filename: string | null } | undefined {
+  if (typeof value !== 'string') return undefined;
+  const trimmed = value.trim();
+  // A root path only: a relative one resolves against the console page, not `/`.
+  if (!trimmed.startsWith('/')) return undefined;
+  const thisOrigin = 'http://runtime-assets.invalid';
+  let resolved: URL;
+  try {
+    resolved = new URL(trimmed, thisOrigin);
+  } catch {
+    return undefined;
+  }
+  // `//host/…`, and `/\host/…` which a browser reads the same way, name another host.
+  if (resolved.origin !== thisOrigin) return undefined;
+  const pathname = resolved.pathname;
+  if (!pathname.startsWith(RUNTIME_ASSETS_URL_PREFIX)) return undefined;
+  const segment = pathname.slice(RUNTIME_ASSETS_URL_PREFIX.length);
+  if (segment === '') return undefined;
+  if (segment.includes('/')) return { url: pathname, filename: null };
+  // The route reads its parameter decoded; an undecodable one stays raw here.
+  let filename = segment;
+  try {
+    filename = decodeURIComponent(segment);
+  } catch {
+    /* keep the raw segment */
+  }
+  return { url: pathname, filename };
+}
+
+/** The branding keys whose value the console draws as an image URL. */
+const BRANDING_IMAGE_KEYS = ['logo', 'favicon'] as const;
+
+/**
+ * The apps the console is served: the same `protocol.getMetaItems({ type:
+ * 'app' })` read `GET /api/v1/meta/app` answers from, which the console's app
+ * list and chrome (logo, favicon) are drawn from. It covers config boots and
+ * artifact boots alike, because both register their apps with that protocol.
+ */
+async function readServedApps(ctx: any): Promise<any[]> {
+  const protocol = ctx.getService('protocol');
+  if (typeof protocol?.getMetaItems !== 'function') return [];
+  const answer = await protocol.getMetaItems({ type: 'app' });
+  const items = Array.isArray(answer) ? answer : answer?.items;
+  return Array.isArray(items) ? items : [];
+}
+
+/**
+ * One line per branding URL under `/runtime/assets/` that this boot will not
+ * serve, naming every app and key that uses it, the file, the directory
+ * searched, `OS_RUNTIME_ASSETS_DIR`, and whether that directory exists at all.
+ * Empty when every such URL resolves to a servable file.
+ */
+function describeUnservedBrandingAssets(
+  apps: any[],
+  assetsDir: string,
+  mounted: boolean,
+  dirSource: RuntimeAssetsDirSource,
+): string[] {
+  const unserved = new Map<string, { filename: string | null; uses: Map<string, string[]> }>();
+  for (const app of apps) {
+    const appName = String(app?.name ?? app?.id ?? '(unnamed)');
+    for (const key of BRANDING_IMAGE_KEYS) {
+      const request = runtimeAssetRequest(app?.branding?.[key]);
+      if (!request) continue;
+      if (mounted && request.filename !== null && runtimeAssetIsServable(assetsDir, request.filename)) continue;
+      const entry = unserved.get(request.url) ?? { filename: request.filename, uses: new Map<string, string[]>() };
+      entry.uses.set(appName, [...(entry.uses.get(appName) ?? []), `branding.${key}`]);
+      unserved.set(request.url, entry);
+    }
+  }
+
+  const searched = dirSource === 'OS_RUNTIME_ASSETS_DIR'
+    ? `${assetsDir} (named by OS_RUNTIME_ASSETS_DIR)`
+    : `${assetsDir} (the <cwd>/assets default, since OS_RUNTIME_ASSETS_DIR is unset)`;
+  const lines: string[] = [];
+  for (const [url, { filename, uses }] of unserved) {
+    const users = [...uses].map(([appName, keys]) => `app '${appName}' (${keys.join(', ')})`).join(' and ');
+    const file = filename ?? url.slice(RUNTIME_ASSETS_URL_PREFIX.length);
+    const reason = !mounted
+      ? `the directory searched, ${searched}, does not exist, so ${RUNTIME_ASSETS_URL_PREFIX} is not mounted this run`
+      : filename === null
+        ? `${RUNTIME_ASSETS_URL_PREFIX} serves only files directly inside the directory searched, ${searched}, never a subdirectory`
+        : `${file} is not a readable file in the directory searched, ${searched}`;
+    const remedy = filename === null
+      ? `move the file to the top of that directory and drop the subdirectory from the URL, or set OS_RUNTIME_ASSETS_DIR to a directory that holds it at the top`
+      : `put ${file} in that directory${mounted ? '' : ' and restart'}, or set OS_RUNTIME_ASSETS_DIR to the directory that holds it`;
+    lines.push(
+      `Branding asset not served: ${users} → ${url}, but ${reason}; the console will draw a broken image. To fix, ${remedy}.`,
+    );
+  }
+  return lines;
+}
+
 /**
  * Create a plugin that serves static runtime assets at /runtime/assets/*.
  * Decoupled from the console plugin so branding assets (logos, favicons) are
  * served even when the console dist hasn't been built yet.
  *
  * The `distPath` should point at the host project's `runtime/assets` directory
  * (i.e. `path.resolve(process.cwd(), 'assets')` when the CLI cwd is the
- * `runtime/` package).
+ * `runtime/` package); `dirSource` says which of the two it came from.
+ *
+ * When the directory is absent the route is not mounted. Either way, once the
+ * boot has settled (`kernel:bootstrapped`), every loaded app's `branding.logo`
+ * / `branding.favicon` that names a file under `/runtime/assets/` which this
+ * route will not serve is reported ONCE, through this plugin's logger at
+ * `warn` (#22071): an artifact booted outside its project directory otherwise
+ * drew a broken logo and favicon with nothing said on either side. That is the
+ * one channel: under `serve`'s boot-quiet window the line is replayed in the
+ * banner's *Boot diagnostics* block, and at `--log-level debug|info` it streams
+ * live. It changes nothing about what the route serves.
  */
-export function createRuntimeAssetsPlugin(distPath: string) {
+export function createRuntimeAssetsPlugin(distPath: string, dirSource: 'OS_RUNTIME_ASSETS_DIR' | 'cwd') {
   return {
     name: 'com.objectstack.runtime-assets',
 
@@ -612,13 +768,29 @@ export function createRuntimeAssetsPlugin(distPath: string) {
 
       const app = httpServer.getRawApp();
       const assetsDir = path.resolve(distPath);
-      if (!fs.existsSync(assetsDir)) return;
+      const mounted = fs.existsSync(assetsDir);
+
+      // After every `kernel:ready` handler has settled, so an app a later
+      // plugin registers on that hook is read too. A best-effort report: it
+      // must never fail the boot it reports on.
+      ctx.hook('kernel:bootstrapped', async () => {
+        let apps: any[];
+        try {
+          apps = await readServedApps(ctx);
+        } catch (err: any) {
+          ctx.logger.debug(`Branding asset check skipped: the served app list could not be read (${err?.message ?? err})`);
+          return;
+        }
+        for (const line of describeUnservedBrandingAssets(apps, assetsDir, mounted, dirSource)) {
+          ctx.logger.warn(line);
+        }
+      });
+
+      if (!mounted) return;
 
       app.get('/runtime/assets/:filename', async (c: any) => {
-        const filename = String(c.req.param?.('filename') ?? '').replace(/[/\\]+/g, '');
-        const filePath = path.join(assetsDir, filename);
-        // Path-traversal guard: reject any path that escapes assetsDir.
-        if (!path.resolve(filePath).startsWith(path.resolve(assetsDir))) {
+        const filePath = resolveRuntimeAssetPath(assetsDir, String(c.req.param?.('filename') ?? ''));
+        if (filePath === null) {
           return c.text('Forbidden', 403);
         }
         try {