Marathon Strategy RAG — a coach that cites its sources

A marathon coach that cites its sources. Ask a race-strategy question and get practical advice grounded in real marathon science — and in my own data analyses of 30,000+ Boston finishers.

You

Should I try to negative-split my first marathon?

Coach

Probably not as a goal. In 31,912 Boston finishers only 2.5% actually ran a negative split, and ~94% slowed — median +14% [1]. Aim for an even effort instead: hold back slightly through halfway so you're not part of the 27% who fall apart after 30 km [2].

Why a citing coach?

Running advice is everywhere and a plain chatbot will invent statistics with total confidence. This coach answers only from a curated knowledge base and cites every claim with a [n] that traces back to a real source — established training science, or one of my own published marathon analyses.

📊

Grounded in real data

Cards distilled from my analyses of the Boston field — negative splits, the wall, the heat tax, course difficulty, super-shoes.

🔎

Every claim cited

Answers carry [n] citations back to the exact knowledge card — no invented numbers.

🆓

Free & local

Embeddings and search run on your machine with sentence-transformers + Chroma. The knowledge base ships in the repo.

🧩

Easily extended

Add a markdown card, re-index, and the coach can cite it — no retraining.

How it works

Under the hood: generation runs on the Claude CLI by default (uses your Claude subscription, no per-token cost); set ANTHROPIC_API_KEY to use the API instead. Retrieval is always local and free.