You can ask Deeta things without opening it first. Useful when your hands are busy.
Asking
Say it in three parts, pausing between each:
"Hey Siri" … "Ask Deeta" … then, when Siri asks "What would you like to ask?", say "Who do I know in Bristol?"
Siri then opens Deeta and runs the question there. The question can't be included in the same breath as "Ask Deeta" — Siri needs to ask for it.
Setting it up
Nothing to set up. Deeta registers the shortcut when you install it — say the phrase and it works.
Settings → AI → Use Deeta with Siri explains it in the app, and you'll find the shortcut listed in your iPhone's Shortcuts app under Deeta.
Saving something with Siri
You can also send text to Deeta from other apps and from Shortcuts, and pick who it's about. See Turning what you say into deets.
Troubleshooting
Siri says it doesn't know about Deeta. Open Deeta once first — shortcuts register on first launch. If it still doesn't work, delete and reinstall Deeta, which re-registers everything.
Siri opened Deeta but nothing was asked. The question didn't come through. Say "Ask Deeta" first, wait for Siri to ask what you'd like to ask, then say the question.
Siri mishears "Deeta". Say it clearly, with a short pause after "Hey Siri".
It works on my iPhone but not my other devices. Shortcuts register per device. Open Deeta once on each.
Nothing happened at all. Check Siri is on (Settings → Apple Intelligence & Siri) and that Deeta appears under Siri's app list.
Siri says "Ask Deeta isn't available here right now." Asking through Siri can be switched off in some regions or for a while. Ask in the AI tab instead. When it's off, the Use Deeta with Siri row is hidden in Settings too.
Questions
Does Siri hear my contacts? No. Siri hears your question, and Apple processes those words as with any Siri request. Deeta answers it, and Apple isn't given your contacts.
Does it use my monthly allowance? Yes, the same allowance as asking in the app — unless you're in Private Mode, which is unmetered. See Choosing how your questions are answered.
Can Siri read the answer aloud? Not currently — Deeta opens and shows it.
Can I use it with a HomePod or CarPlay? The question is handed to Deeta on your iPhone, so you'll need your phone to see the answer.