fix(cli): print "Nothing to update." when update finds nothing installed

docs/cli-reference.md

@@ -419,7 +419,8 @@ is sent only over `https`; plain `http` is refused except for `localhost`,
   collection install replaces its own lock. Installing into a lock of another
   scope is a `usage_error` (pass `--lock other.json` or `--no-lock`).
 - **update** re-resolves installed sources (all, or those named) and applies the
-  difference, then refreshes the lock file when its scope was updated.
+  difference, then refreshes the lock file when its scope was updated. With
+  nothing installed it prints `Nothing to update.` (`--json`: empty `outcomes`).
 - **uninstall** drops a kit, a collection, or one or more packages; each
   explicit package is its own source (`packages:@scope/name`), whether it was
   installed alone, with others, or by `sync --locked` from a packages lock.

packages/cli/src/commands/install-update.test.ts

@@ -0,0 +1,41 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { InstallLock } from '@skillx/contracts';
+import type { ApplyOutcome } from '../lib/install/install-operations.js';
+import { printUpdated } from './install.js';
+
+const outcome: ApplyOutcome = {
+  lock: {} as InstallLock,
+  lockDigest: 'sha256:lock',
+  items: [],
+  planDigest: 'sha256:plan',
+  warnings: [],
+  applied: [],
+  recovered: { rolledBack: [], rolledForward: [] },
+};
+
+let out: string[];
+
+beforeEach(() => {
+  out = [];
+  vi.spyOn(console, 'log').mockImplementation((...args: unknown[]) => void out.push(args.join(' ')));
+});
+
+afterEach(() => vi.restoreAllMocks());
+
+describe('printUpdated', () => {
+  it('says so when nothing is installed', () => {
+    printUpdated({ outcomes: [], lockPath: null });
+    expect(out.join('\n')).toContain('Nothing to update.');
+  });
+
+  it('prints each applied source and no empty-state line', () => {
+    printUpdated({ outcomes: [outcome, outcome], lockPath: '/tmp/skillx.lock.json' });
+    const text = out.join('\n');
+    expect(text).not.toContain('Nothing to update.');
+    expect(text.match(/✓ done/g)).toHaveLength(2);
+    // The lock line follows only the last source.
+    expect(text.match(/lock written to/g)).toHaveLength(1);
+    expect(text.trimEnd().endsWith('✓ done')).toBe(true);
+    expect(text.lastIndexOf('lock written to /tmp/skillx.lock.json')).toBeGreaterThan(text.indexOf('✓ done'));
+  });
+});

packages/cli/src/commands/install.ts

@@ -38,6 +38,12 @@ function printApplied(outcome: ApplyOutcome, lockPath: string | null): void {
   console.log(chalk.green('\n✓ done'));
 }
 
+/** Human mode for `update`: each applied source, or one line when nothing is installed. */
+export function printUpdated(data: { outcomes: ApplyOutcome[]; lockPath: string | null }): void {
+  if (data.outcomes.length === 0) console.log(chalk.dim('Nothing to update.'));
+  data.outcomes.forEach((o, i) => printApplied(o, i === data.outcomes.length - 1 ? data.lockPath : null));
+}
+
 export const installCommand = withCommon(new Command('install'))
   .description('Install a kit revision, a collection or packages into a runtime skills directory')
   .argument('<refs...>', 'kit:@handle/kit[#revisionId] | collection:<id>[#n] | @publisher/package[@version]...')
@@ -80,7 +86,7 @@ export const updateCommand = withCommon(new Command('update'))
         }
         return { outcomes, lockPath };
       },
-      (data) => data.outcomes.forEach((o, i) => printApplied(o, i === data.outcomes.length - 1 ? data.lockPath : null)),
+      printUpdated,
     ),
   );