OnCall Hero

💡 Inspiration

Scheduling service appointments (dentists, auto repair, salons, clinics) often means waiting on hold, dealing with busy phone lines, or navigating awkward back-and-forth scheduling calls. We wanted to build an autonomous AI agent that takes this burden off the user's shoulders—picking up the phone, calling businesses directly, negotiating appointment times, and returning structured results.

☎️ What it does

OnCall Hero is an autonomous AI booking assistant powered by CALL-E. Users simply provide:

1. Service Provider Name
2. Target Phone Number (E.164 format)
3. Customer Name
4. Desired Appointment Time
5. Service Type & Optional Instructions

Once dispatched, OnCall Hero places a real-time phone call to the provider, politely greets the receptionist, requests the desired slot, handles alternative times if needed, confirms booking details, and updates the user with a structured summary in real time.

🛠️ How we built it

• Backend: Built with Node.js and Express.js to handle API requests and manage in-memory call activity logs.
• AI Telephony: Integrated @call-e/calle SDK to construct dynamic system prompts and trigger automated phone interactions via client.calls.createAndWait().
• Frontend: A responsive dashboard interface built with HTML5 and Tailwind CSS, featuring live call status updates and structured summaries.

🛑 Challenges we ran into

• Prompt Engineering for Voice: Formulating system prompts that sound natural over the phone while strictly adhering to task constraints (capturing confirmation details, handling unavailable slots gracefully).
• Asynchronous Execution & UX: Ensuring the web dashboard provided real-time feedback while waiting 30–60 seconds for the telephone conversation to conclude.

🎉 Accomplishments that we're proud of

• Successfully executing end-to-end automated telephone calls through the CALL-E SDK.
• Extracting structured outputs (taskCompleted, status, summary) directly from conversational outcomes.
• Building a clean, intuitive developer-friendly dashboard interface.

📚 What we learned

• How to effectively structure prompts for conversational voice AI agents using CALL-E's task paradigm.
• Best practices for E.164 phone number handling, fallback scheduling logic, and error management.

🚀 What's next for OnCall Hero

• Calendar Integration: Automatically sync confirmed appointments to Google Calendar / Outlook.
• SMS/WhatsApp Notifications: Send immediate booking confirmations and call transcripts to the customer's phone.
• Multi-call Parallel Dispatch: Allow users to query multiple providers simultaneously for the earliest available slot.

Built With

• api
• call-e
• css
• express.js
• html
• javascript
• node.js
• rest
• sdk
• tailwind