feat: prefer bun runtime (#435)

scripts/postinstall-patches.js

@@ -1,7 +1,14 @@
 // Postinstall patcher for vendoring our Ink modifications without patch-package.
 // Copies patched runtime files from ./src/vendor into node_modules.
 
-import { copyFileSync, existsSync, mkdirSync } from "node:fs";
+import { execSync } from "node:child_process";
+import {
+  copyFileSync,
+  existsSync,
+  mkdirSync,
+  readFileSync,
+  writeFileSync,
+} from "node:fs";
 import { createRequire } from "node:module";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
@@ -101,3 +108,27 @@ await copyToResolved(
 );
 
 console.log("[patch] Ink runtime patched");
+
+// On Unix with Bun available, use polyglot shebang to prefer Bun runtime.
+// This enables Bun.secrets for secure keychain storage instead of fallback.
+// Windows always uses #!/usr/bin/env node (polyglot shebang breaks npm wrappers).
+if (process.platform !== "win32") {
+  try {
+    execSync("bun --version", { stdio: "ignore" });
+    const lettaPath = join(pkgRoot, "letta.js");
+    if (existsSync(lettaPath)) {
+      let content = readFileSync(lettaPath, "utf-8");
+      if (content.startsWith("#!/usr/bin/env node")) {
+        content = content.replace(
+          "#!/usr/bin/env node",
+          `#!/bin/sh
+":" //#; exec /usr/bin/env sh -c 'command -v bun >/dev/null && exec bun "$0" "$@" || exec node "$0" "$@"' "$0" "$@"`,
+        );
+        writeFileSync(lettaPath, content);
+        console.log("[patch] Configured letta to prefer Bun runtime");
+      }
+    }
+  } catch {
+    // Bun not available, keep node shebang
+  }
+}

src/settings-manager.ts

@@ -4,6 +4,7 @@
 import { homedir } from "node:os";
 import { join } from "node:path";
 import type { PermissionRules } from "./permissions/types";
+import { debugWarn } from "./utils/debug.js";
 import { exists, mkdir, readFile, writeFile } from "./utils/fs.js";
 import {
   deleteSecureTokens,
@@ -131,15 +132,14 @@ class SettingsManager {
     try {
       const available = await this.isKeychainAvailable();
       if (!available) {
-        console.warn(
-          "⚠️  System secrets are not available - using fallback storage",
-        );
-        console.warn(
-          "   This may occur when running in Node.js or restricted environments",
+        // Only show warning in debug mode - fallback storage is expected for npm users
+        debugWarn(
+          "secrets",
+          "System secrets not available - using fallback storage",
         );
       }
     } catch (error) {
-      console.warn("⚠️  Could not check secrets availability:", error);
+      debugWarn("secrets", `Could not check secrets availability: ${error}`);
     }
   }