FixFast: Autonomous emergency contractor dispatch agent.

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  Final Inference

Inspiration

When a property emergency strikes at 2 AM—a burst pipe, electrical outage, or broken lock—calling multiple contractors manually is stressful, slow, and unreliable. Most emergency services either don't answer, quote unreasonable rates, or give vague ETAs. We set out to build FixFast: an autonomous voice agent that takes immediate control in crisis moments by calling, negotiating, and dispatching contractors in real-time without requiring human intervention.

What it does

FixFast is an autonomous phone-dispatch agent powered by CALL-E that handles emergency contractor dispatching from start to finish:

• Outbound Voice Negotiation: Automatically dials local trade professionals (plumbers, HVAC technicians, electricians, locksmiths).
• Constraint Validation: Negotiates pricing against a maximum budget and verifies arrival time against an ETA limit .
• Instant Booking & Lock: Secures the first qualified contractor who accepts the terms and instantly halts all active/pending calls to prevent double-booking.

How we built it

• Voice & Call Engine: Powered by CALL-E to conduct real-time, natural human speech conversations and negotiations over standard phone lines.
• Backend State Machine: Built with Python to manage dispatch queues, evaluate negotiation parameters dynamically, and process CALL-E webhooks.
• Mathematical Concurrency Control: Implemented an atomic locking mechanism to guarantee zero double-booking errors during parallel dialing. As soon as one contractor confirms, all secondary active calls are atomically transitioned to an automated, polite cancellation prompt.

Challenges we ran into

• Handling Unpredictable Voice Responses: Contractors often speak informally or interrupt during emergency calls. Fine-tuning prompt structures in CALL-E to strictly extract numerical price quotes and arrival times while maintaining natural conversation flow took significant iteration.
• Race Condition Prevention: Managing real-time Webhook responses when two contractors answered and accepted terms within seconds of each other required strict atomic mutex locks on the backend database.

Accomplishments that we're proud of

• Zero Double-Booking Prevention: Proved that concurrent outbound voice agents can safely operate in high-stakes environments without duplicate dispatches.
• Seamless CALL-E Integration: Created an agent capable of real-time price negotiation under strict business logic constraints.
• End-to-End Execution: Developed a functional pipeline from emergency trigger to real phone call dispatch.

What we learned

• How to structure LLM voice system prompts for rigid numeric extraction (ETA and cost) during fluid phone conversations.
• Designing resilient fallback paths and state transitions when interacting with external real-world physical services via voice APIs.

What's next for FixFast: Autonomous emergency contractor dispatch agent.

• Escrow & Instant Payments: Integrating payment gateway pre-authorization to hold funds and pay contractors automatically upon job verification.
• PMS Integrations: Connecting FixFast directly into tenant property management platforms (e.g., AppFolio, Buildium) to handle incoming maintenance tickets 24/7.
• Multilingual Negotiations: Adding multi-language support to seamlessly negotiate across diverse contractor networks.
• Google Maps: Enabling local vendor/contractor search by using google maps.

Built With

• call-e
• nextjs
• tailwind
• typescript