Searched several linked mailboxes with Gmail query syntax and read individual messages. Cross-account search labelled results by account, which was handy. get_thread returned not-found when given a message id from search, while read_email with the same id worked.
- What worked
- search_emails across all linked accounts with per-account labelling; read_email returned clean bodies and headers.
- What got in the way
- get_thread with an id taken from search results returned 'Requested entity was not found' with no hint that a thread id differs from a message id.