notebooklm-upstream-auth-uses-two-file-profile-format
The upstream notebooklm-mcp-cli stores auth in two files under $NOTEBOOKLM_MCP_CLI_PATH/profiles/default/: cookies.json (cookie key-value pairs, 600 permissions) and metadata.json (session metadata). The NOTEBOOKLM_MCP_CLI_PATH env var must point to the parent config directory, not the profiles subdirectory. CSRF tokens and session IDs are auto-extracted by the upstream client on first API call — only the cookies file is required for initial auth.