fix: auto-resolve LETTABOT_API_KEY from lettabot-api.json (#367)

src/api/auth.ts

@@ -21,7 +21,38 @@ export function generateApiKey(): string {
 }
 
 /**
- * Load API key from file or environment, or generate new one
+ * Load API key from environment or file. Throws if not found.
+ * Use this in CLI tools where generating a new key would be incorrect.
+ */
+export function loadApiKey(): string {
+  // 1. Check environment variable first
+  if (process.env.LETTABOT_API_KEY) {
+    return process.env.LETTABOT_API_KEY;
+  }
+
+  // 2. Try to load from file
+  const filePath = path.resolve(process.cwd(), API_KEY_FILE);
+  if (fs.existsSync(filePath)) {
+    try {
+      const data = fs.readFileSync(filePath, 'utf-8');
+      const store: ApiKeyStore = JSON.parse(data);
+      if (store.apiKey && typeof store.apiKey === 'string') {
+        return store.apiKey;
+      }
+    } catch {
+      // Fall through to error
+    }
+  }
+
+  throw new Error(
+    'API key not found. Start the lettabot server first (it generates lettabot-api.json), ' +
+    'or set LETTABOT_API_KEY environment variable.'
+  );
+}
+
+/**
+ * Load API key from file or environment, or generate new one.
+ * Use this on the server side where generating a key on first run is expected.
  */
 export function loadOrGenerateApiKey(): string {
   // 1. Check environment variable first

src/cli/message.ts

@@ -12,6 +12,7 @@
 
 // Config loaded from lettabot.yaml
 import { loadAppConfigOrExit, applyConfigToEnv } from '../config/index.js';
+import { loadApiKey } from '../api/auth.js';
 const config = loadAppConfigOrExit();
 applyConfigToEnv(config);
 import { existsSync, readFileSync } from 'node:fs';
@@ -150,11 +151,8 @@ async function sendViaApi(
   }
 ): Promise<void> {
   const apiUrl = process.env.LETTABOT_API_URL || 'http://localhost:8080';
-  const apiKey = process.env.LETTABOT_API_KEY;
-
-  if (!apiKey) {
-    throw new Error('LETTABOT_API_KEY not set. Check bot server logs for the key.');
-  }
+  // Resolve API key: env var > lettabot-api.json (never generate -- that's the server's job)
+  const apiKey = loadApiKey();
 
   // Check if file exists
   if (options.filePath && !existsSync(options.filePath)) {
@@ -357,7 +355,7 @@ Environment variables:
   SLACK_BOT_TOKEN         Required for Slack
   DISCORD_BOT_TOKEN       Required for Discord
   SIGNAL_PHONE_NUMBER     Required for Signal (text only, no files)
-  LETTABOT_API_KEY        Required for WhatsApp (text and files)
+  LETTABOT_API_KEY        Override API key (auto-read from lettabot-api.json if not set)
   LETTABOT_API_URL        API server URL (default: http://localhost:8080)
   SIGNAL_CLI_REST_API_URL Signal daemon URL (default: http://127.0.0.1:8090)