What Happened

NotebookLM upload skill failed with “Auth required” even after user completed browser auth flow.

Investigation

Shell script (notebook.sh) checked for auth like this:

AUTH_FILE="$AUTH_DIR/notebook-lm-auth.json"
if [[ ! -f "$AUTH_FILE" ]]; then
    echo "Auth required..."
fi

But TypeScript upload script (upload.ts) actually used Chrome profile:

const AUTH_DIR = join(homedir(), ".config", "moltbot", "notebook-lm-chrome");
// ... launches browser with userDataDir

The auth flow saved a Chrome profile directory, not a JSON file. The shell script checked for the wrong artifact.

Resolution

Fixed shell script to check for Chrome profile instead:

CHROME_PROFILE="$AUTH_DIR/notebook-lm-chrome/Default"
if [[ ! -d "$CHROME_PROFILE" ]]; then
    echo "Auth required..."
fi

Lesson

When integrating scripts in different languages, verify the actual artifacts each component creates.

Common pattern: Shell wrapper → TypeScript implementation. The wrapper often makes assumptions about what the implementation does. Always trace the actual file/directory creation path.

Debugging Tip

# Before: "Why doesn't auth work?"
ls -la ~/.config/moltbot/notebook-lm*
# Reveals: notebook-lm-chrome/ exists, notebook-lm-auth.json does not