Enhancement: Allow Context.send to utilize 'source_only' argument for PartialUser.send_message

[ImitativeRemi]

Summary

For sending chat messages using ctx.send for a command function, currently it only uses the sender and message arguments, and does not pass any other arguments to the send_message function.

TwitchIO/twitchio/ext/commands/context.py

Line 546 in 28be549

return await self.channel.send_message(sender=self.bot.bot_id, message=new)

It would be neat to use the 'source_only' argument such that custom chat bot accounts can have their messages not appear in other people's chat during a Shared Chat session.

However, I'm not sure on if the tokens that are generated from the Quickstart are the required 'App Access Token' that's required for using the 'for_source_only' parameter in the Send Chat Message API:

https://discuss.dev.twitch.com/t/adding-for-source-only-parameter-for-shared-chat-and-a-behavior-update-for-send-chat-message-api-endpoint-may-19-2025/63261

Basic Examples

No response

Drawbacks and Impact

No response

Unresolved questions

No response

[chillymosh]

Currently Context.send() will use the Twitch default of True for source_only, when an app token is used. Which means it will only send to source, as Context.send() only uses an app token.

We could expose source_only to allow disabling this feature, although it's not recommended, and most likely not really ever desired.

For sending as a User Token can utilise await ctx.broadcaster.send_message("message", sender_id=self.bot.bot_id, token_for=self.bot.bot_id).