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Lightning - Fantasy GM Agent

An agentic product for NBA fantasy basketball. A LangGraph + Claude agent reasons over live Yahoo Fantasy league data and recommends trades and waiver pickups.

Type
Independent product, deployed
Stack
LangGraph, Claude, FastAPI, React, Postgres, LangSmith
Status
Live demo
Link
fantasy-gm-agent.vercel.app ↗
Lightning - Fantasy GM Agent

Overview

Fantasy basketball managers make a steady stream of small decisions: which player to pick up, which trade to accept, who to drop. Lightning is an agent that looks at the live state of a Yahoo Fantasy league and gives recommendations for those decisions.

What I built

  • Agent. A LangGraph agent using Claude that reasons over live Yahoo Fantasy data to recommend trades and waiver pickups.
  • Backend. FastAPI service with Postgres for persistence.
  • Interface. A React app with a chat view, a dashboard and a trade analyzer.
  • Evaluation. LangSmith evals used as a quality gate before each release.

Design choices

I built the product end to end, from the agent to the deployed UI. Evals run before each release, so changes to prompts and tools are checked against a fixed set of cases before they reach users.