nlm-login-manual-file-accepts-cookies-json-format
The upstream nlm login —manual —file flag accepts a cookies.json file directly (the same format as profiles/default/cookies.json). This provides a programmatic injection path that bypasses the interactive Chrome CDP flow. However if the cookies originated from a different HTTP client (e.g., notebooklm-py), Google will still reject them at the RPC layer due to client fingerprint mismatch — the injection succeeds but API calls fail.