How Mercado Libre built an AI-native operation for buying and selling used cars

In just ten weeks, Mercado Libre and Wonderful went to three AI agents in production across Mercado Libre Vehículos in Mexico. In its first runs, the deployment handled roughly 99% of conversations without human intervention and issued close to 2,200 quotes.

The challenge

Mercado Libre is Latin America's largest marketplace. Within Mercado Libre Vehículos, selling a used car is a high-consideration transaction, with multiple steps between a seller's initial interest and an in-person vehicle inspection.

Every point where a seller has to wait or repeat information creates an opportunity for the transaction to drop off.

Wonderful and Mercado Libre set out to create an AI agent that could accompany sellers through this process in a single conversation, from sharing their vehicle details and receiving a valuation through to scheduling an inspection.

Building it

Wonderful and Mercado Libre co-created an AI agent that runs on WhatsApp, the country's most widely used messaging channel.

The agent guides used-car sellers from the moment they share their vehicle details through to scheduling an in-person inspection, without human intervention in the flow.

The agent operates on a five-skill architecture:

1. Vehicle registration

2. Trim identification

3. Pricing

4. Appointment scheduling

5. Answers to frequently asked questions

Throughout the process, the agent draws on used-car domain expertise and transaction-specific know-how to guide sellers and reduce drop-off during the transaction.

Building into the buying and selling experience

Wonderful worked hand in hand with Mercado Libre's team to build the foundation across Mercado Libre's core systems from the start.

As Mariano Nunes, General Manager of Vehículos Mercado Libre México, described it, the solution was built directly into the buying and selling experience rather than working separately. This allows the agents to behave as part of the user journey rather than something bolted onto it.

The deployment is complemented by operational applications that allow a human to step in when needed and give Mercado Libre visibility into agent performance for its day-to-day operation.

From kickoff to three agents in production in ten weeks

The entire program, from the first immersion session to the go-live of three agents, took just ten weeks.

The deployment comprises three agents in production:

• Seller agent, which guides used-car sellers through the process from vehicle details to inspection scheduling

• Buyer-seller agent, which connects buyers with sellers

• Auctions agent, which works with Mercado Libre's network of authorized dealerships

All three agents are now active in the market.

The impact

The deployment quickly demonstrated what an AI-native operation can look like in production:

• ~99% of conversations handled without human intervention

• Close to 2,200 quotes issued in its first weeks

• 49% week-over-week growth

Rather than automating a single step, the seller agent manages the journey from the first message through to an in-person inspection, providing a valuation and guiding the seller through the process in a single conversation.

Expanding within Mercado Libre Vehículos

With three agents already in production, Mercado Libre and Wonderful plan to open the agent flow to a larger share of traffic within Mercado Libre Vehículos and add further use cases in the same vertical.

"This solution lets us meet the seller at their first message with a valuation and guide them through a single conversation all the way to the inspection. Together with Wonderful's team, we built the solution directly into the buying and selling experience rather than working separately. This is why the agents behave as part of the user journey rather than something bolted onto it."

Mariano Nunes, General Manager of Vehículos Mercado Libre México