Mark Gmail thread as read
Input
threadId requiredHex legacy thread id (as returned by search_emails).
account optionalGoogle account email to act as (authuser=). Without it Gmail picks u/0, nondeterministic in a multi-account browser jar.
Output
read requiredthreadId requiredpage optionalWhich All Mail page the thread was found on (1-based).
already_read optionaltrue = the thread was already read; nothing was clicked.
Search Gmail
Search the signed-in Gmail with the native query syntax (from:, to:, subject:, has:attachment, after:/before:, labels…) and return matching threads: threadId (feed it to get_thread / reply_to_email), sender, senderEmail, subject, snippet, date, unread, starred, hasAttachment. Results are threads rather than individual messages, which is Gmail's own search granularity, and only the first page of results is returned (up to 50).
Create a Gmail draft
Compose a Gmail message and save it as a draft without sending it. Takes to/cc/bcc, subject and body, and confirms the draft exists in Drafts afterward rather than trusting the compose window closing.
Send Gmail email
Send an email from the signed-in Gmail account, with a plain-text body and an optional single file attachment.