feat: add update command and improve install method detection

src/cli.ts

@@ -16,6 +16,7 @@ import { segmentsCommand } from './commands/segments/index';
 import { teamsDeprecatedCommand } from './commands/teams-deprecated';
 import { templatesCommand } from './commands/templates/index';
 import { topicsCommand } from './commands/topics/index';
+import { updateCommand } from './commands/update';
 import { webhooksCommand } from './commands/webhooks/index';
 import { whoamiCommand } from './commands/whoami';
 import { errorMessage, outputError } from './lib/output';
@@ -90,6 +91,7 @@ ${pc.gray('Examples:')}
   .addCommand(authCommand)
   .addCommand(openCommand)
   .addCommand(whoamiCommand)
+  .addCommand(updateCommand)
   .addCommand(teamsDeprecatedCommand);
 
 // Hide the deprecated --team option from help
@@ -100,7 +102,14 @@ if (teamOption) {
 
 program
   .parseAsync()
-  .then(() => checkForUpdates().catch(() => {}))
+  .then(() => {
+    // Skip the background update notice when the user explicitly ran `update`
+    const ran = program.args[0];
+    if (ran === 'update') {
+      return;
+    }
+    return checkForUpdates().catch(() => {});
+  })
   .catch((err) => {
     outputError({
       message: errorMessage(err, 'An unexpected error occurred'),

src/commands/update.ts

@@ -0,0 +1,70 @@
+import { Command } from '@commander-js/extra-typings';
+import type { GlobalOpts } from '../lib/client';
+import { buildHelpText } from '../lib/help-text';
+import { outputError, outputResult } from '../lib/output';
+import { createSpinner } from '../lib/spinner';
+import { isInteractive } from '../lib/tty';
+import {
+  detectInstallMethod,
+  fetchLatestVersion,
+  isNewer,
+} from '../lib/update-check';
+import { VERSION } from '../lib/version';
+
+export const updateCommand = new Command('update')
+  .description('Check for available CLI updates')
+  .addHelpText(
+    'after',
+    buildHelpText({
+      context: `Checks the latest release on GitHub (bypasses the cache).
+Shows the current version, latest version, and how to upgrade.`,
+      output: `  {"current":"1.4.0","latest":"1.5.0","update_available":true,"upgrade_command":"npm install -g resend-cli"}
+  {"current":"1.5.0","latest":"1.5.0","update_available":false}`,
+      examples: ['resend update', 'resend update --json'],
+    }),
+  )
+  .action(async (_opts, cmd) => {
+    const globalOpts = cmd.optsWithGlobals() as GlobalOpts;
+    const interactive = isInteractive() && !globalOpts.json;
+
+    const spinner = interactive
+      ? createSpinner('Checking for updates...')
+      : null;
+
+    const latest = await fetchLatestVersion();
+
+    if (!latest) {
+      spinner?.fail('Could not check for updates');
+      outputError(
+        { message: 'Could not reach GitHub releases', code: 'fetch_failed' },
+        { json: globalOpts.json },
+      );
+      return;
+    }
+
+    const updateAvailable = isNewer(VERSION, latest);
+    const upgrade = detectInstallMethod();
+
+    if (globalOpts.json || !isInteractive()) {
+      outputResult(
+        {
+          current: VERSION,
+          latest,
+          update_available: updateAvailable,
+          ...(updateAvailable ? { upgrade_command: upgrade } : {}),
+        },
+        { json: globalOpts.json },
+      );
+      return;
+    }
+
+    if (updateAvailable) {
+      const isUrl = upgrade.startsWith('http');
+      spinner?.warn(`Update available: v${VERSION} → v${latest}`);
+      console.log(
+        `\n  ${isUrl ? 'Visit' : 'Run'}: \x1B[36m${upgrade}\x1B[0m\n`,
+      );
+    } else {
+      spinner?.stop(`Already up to date (v${VERSION})`);
+    }
+  });

src/lib/update-check.ts

@@ -32,7 +32,7 @@ function writeState(state: UpdateState): void {
 /**
  * Compare two semver strings. Returns true if remote > local.
  */
-function isNewer(local: string, remote: string): boolean {
+export function isNewer(local: string, remote: string): boolean {
   const parse = (v: string) => v.replace(/^v/, '').split('.').map(Number);
   const [lMaj, lMin, lPat] = parse(local);
   const [rMaj, rMin, rPat] = parse(remote);
@@ -45,7 +45,7 @@ function isNewer(local: string, remote: string): boolean {
   return rPat > lPat;
 }
 
-async function fetchLatestVersion(): Promise<string | null> {
+export async function fetchLatestVersion(): Promise<string | null> {
   try {
     const res = await fetch(GITHUB_RELEASES_URL, {
       headers: { Accept: 'application/vnd.github.v3+json' },
@@ -89,19 +89,26 @@ function shouldSkipCheck(): boolean {
   return false;
 }
 
-function detectInstallMethod(): string {
+export function detectInstallMethod(): string {
   const execPath = process.execPath || process.argv[0] || '';
+  const scriptPath = process.argv[1] || '';
+
+  // npm / npx global install — check first because npm_execpath and
+  // the script path inside node_modules are the most reliable signals,
+  // even when Node itself was installed via Homebrew.
+  if (
+    process.env.npm_execpath ||
+    /node_modules/.test(scriptPath) ||
+    /node_modules/.test(execPath)
+  ) {
+    return 'npm install -g resend-cli';
+  }
 
-  // Homebrew
+  // Homebrew (direct tap install, not npm-via-brew)
   if (/\/(Cellar|homebrew)\//i.test(execPath)) {
     return 'brew update && brew upgrade resend';
   }
 
-  // npm / npx global install
-  if (/node_modules/.test(execPath) || process.env.npm_execpath) {
-    return 'npm install -g resend-cli';
-  }
-
   // Install script (default install location)
   if (/[/\\]\.resend[/\\]bin[/\\]/.test(execPath)) {
     if (process.platform === 'win32') {

tests/lib/update-check.test.ts

@@ -16,7 +16,10 @@ import {
   test,
   vi,
 } from 'vitest';
-import { checkForUpdates } from '../../src/lib/update-check';
+import {
+  checkForUpdates,
+  detectInstallMethod,
+} from '../../src/lib/update-check';
 import { VERSION } from '../../src/lib/version';
 import { captureTestEnv } from '../helpers';
 
@@ -177,3 +180,60 @@ describe('checkForUpdates', () => {
     expect(stderrOutput).toBe('');
   });
 });
+
+describe('detectInstallMethod', () => {
+  const restoreEnv = captureTestEnv();
+  let origExecPath: string;
+  let origArgv1: string | undefined;
+
+  beforeEach(() => {
+    origExecPath = process.execPath;
+    origArgv1 = process.argv[1];
+    delete process.env.npm_execpath;
+  });
+
+  afterEach(() => {
+    Object.defineProperty(process, 'execPath', { value: origExecPath });
+    process.argv[1] = origArgv1 as string;
+    restoreEnv();
+  });
+
+  test('detects npm when script path contains node_modules', () => {
+    Object.defineProperty(process, 'execPath', {
+      value: '/opt/homebrew/bin/node',
+    });
+    process.argv[1] = '/opt/homebrew/lib/node_modules/resend-cli/dist/cli.js';
+
+    expect(detectInstallMethod()).toBe('npm install -g resend-cli');
+  });
+
+  test('detects npm when npm_execpath is set even with homebrew node', () => {
+    Object.defineProperty(process, 'execPath', {
+      value: '/opt/homebrew/bin/node',
+    });
+    process.argv[1] = '/opt/homebrew/bin/resend';
+    process.env.npm_execpath =
+      '/opt/homebrew/lib/node_modules/npm/bin/npm-cli.js';
+
+    expect(detectInstallMethod()).toBe('npm install -g resend-cli');
+  });
+
+  test('detects homebrew when no npm signals present', () => {
+    Object.defineProperty(process, 'execPath', {
+      value: '/opt/homebrew/Cellar/resend/1.4.0/bin/resend',
+    });
+    process.argv[1] = '/opt/homebrew/Cellar/resend/1.4.0/libexec/cli.js';
+
+    expect(detectInstallMethod()).toBe('brew update && brew upgrade resend');
+  });
+
+  test('detects install script', () => {
+    Object.defineProperty(process, 'execPath', {
+      value: '/Users/test/.resend/bin/resend',
+    });
+    process.argv[1] = '/Users/test/.resend/bin/resend';
+
+    const expected = process.platform === 'win32' ? 'irm' : 'curl';
+    expect(detectInstallMethod()).toContain(expected);
+  });
+});