How can I pass messages instead of prompts in a non-custom harness?

[shitianfang]

I want to inject the result of an agent in box B completing a task into the tooltip of the messages of the agent in box A to notify the user that the task in box B is complete. This requires manipulating messages, but I found that the default Claude does not support this operation.

[enesakar]

do you want to trigger Box B from Box A? you can orchestrate this using SDK? are you suggesting to enable doing this without any serverful app?

[shitianfang]

I apologize, this is a mistaken requirement, but directly connecting to the box via the frontend without a backend is a genuine need, because serverless transport stream can still time out. I implemented it using a custom harness and Ably AI transport, but it's very time-consuming, and I'd like a simpler, more native way. @enesakar

[shitianfang]

Perhaps this can be solved simply by adjusting the key permissions for subscribing to messages.