It is the 70th minute. Your team leads 1-0. You want to replace your right back, and three players on the bench can cover the position. The coach's instruction is clear: protect the lead.

One candidate likes attacking runs. Another holds his position and provides defensive cover. A third is better at keeping possession.

Football Decider Lab uses this situation to test how Strands Decider follows a coach's instruction when choosing a substitute. I built it for the Strands Decider Hackathon, using Python for the application and a Strands Agent with Amazon Bedrock for the explanation.

The demo uses synthetic match snapshots and player descriptions.…