callin.io "Respond to function call"

Hello community,
I've been encountering a minor issue for some time now.

I'm attempting to feed HTTP request data into my callin.io agent via a callin.io “respond to function call” action, rather than using the response webhook.

Unfortunately, the voice agent isn't vocalizing the results; it's only reading the error message from the fallback option.

I'm quite certain this is due to a specific JSON format required for the agent to interpret it from callin.io. Does anyone know which format is compatible? I've experimented with various formats without success...

Thank you in advance for your help! Wishing everyone a great year 2025!