This post was co-written with Motorway and the AWS Prototyping and AI Customer Engineering (PACE) team.

Motorway, a UK-based online car marketplace, runs a daily auction where up to 8,000 dealers bid on up to 2,500 vehicles. Motorway worked with AWS Prototyping and AI Customer Engineering (PACE) to build an AI-powered dealer stock search agent that transforms how dealers find vehicles, replacing hours of manual filtering with natural language queries.

The challenge

The agent gives a confident-sounding response, but how do you prove it works reliably with real money on the line?

Tool selection errors cause wrong search results, eroding dealer trust.