I'm sure it's a pretty stupid thing I'm missing, but I can't quite see it. My Google Apps Script only needs mail headers so it has a very restrictive scope: "https://www.googleapis.com/auth/gmail.metadata". I really don't want to change this scope because it provides just what I need.

Because of this restrictive scope, many API calls will force you to select the METADATA format instead of the default FULL. This can be checked using the API explorer (https://developers.google.com/gmail/api/v1/reference/users/threads/get). Remember to Select JUST the metadata scope, otherwise it will work! :-)

{ "error": { "errors": [ { "domain": "global", "reason": "forbidden", "message": "Metadata scope doesn't allow format FULL" } ], "code": 403, "message": "Metadata scope doesn't allow format FULL" } } 

Then, from the format drop down menu select "metadata" run again and it will work.

This simple code is enough to replicate the issue:

Code.gs

function getThread() { // get the most recent thread var thread = Gmail.Users.Threads.list('me', {maxResults: 1, fields: 'threads(id)'}); Logger.log('thread: %s', thread); thread = JSON.parse(thread); var threadId = thread.threads[0].id; Logger.log('threadId: %s', threadId); // since my scope is: "https://www.googleapis.com/auth/gmail.metadata" I need to specify the metadata format // next line produces the following error: "Metadata scope doesn't allow format FULL" var thread = Gmail.Users.Threads.get('me', {id: threadId, format: 'metadata'}); } 

appsscript.json

{ "oauthScopes": ["https://www.googleapis.com/auth/gmail.metadata"], "dependencies": { "enabledAdvancedServices": [{ "userSymbol": "Gmail", "serviceId": "gmail", "version": "v1" }] }, "exceptionLogging": "STACKDRIVER" } 

Metadata scope doesn't allow format FULL (line 10, file "Code.gs")

Gmail.Users.Thread.get documentation (https://developers.google.com/gmail/api/v1/reference/users/threads/get) states:

Optional query parameters format string The format to return the messages in.

Acceptable values are:

• "full": Returns the parsed email message content in the payload field and the raw field is not used. (default)
• "metadata": Returns email headers with message metadata such as identifiers and labels.
• "minimal": Only returns email message metadata such as identifiers and labels, it does not return the email headers, body, or payload.

So it's not clear to me how this API call should be written:

var thread = Gmail.Users.Threads.get('me', {id: threadId, format: 'metadata'});

I've tried all the possible combinations of quotes (single, double and no quotes) with case (upper and lower) and nothing has worked... :-(

I'm stumped... please help! :-)

Thanks!!