Ramon Fontelles — Writing https://ramonfontelles.com/articles Notes on AI agents, retrieval, backtesting and trading-system research. en The backtest that lies, and the rules that stop it https://ramonfontelles.com/articles/backtest-that-lies https://ramonfontelles.com/articles/backtest-that-lies A 98% hit rate fell to ~55% with 300 ms of latency. The rules that keep short-horizon backtests honest: bar order, slippage, payout and leakage audits. Fri, 18 Sep 2026 08:00:00 GMT Teaching a debugging agent where to look first https://ramonfontelles.com/articles/debugging-agent-intent-routing https://ramonfontelles.com/articles/debugging-agent-intent-routing Building an AI agent for parasitic-extraction debugging without a vector DB: gated phases, hybrid lexical search, benchmarks and intent routing. Fri, 18 Sep 2026 08:00:00 GMT HFT feature explorer: one recorded 15-minute SOL market https://ramonfontelles.com/articles/hft-feature-explorer https://ramonfontelles.com/articles/hft-feature-explorer Explore 15 minutes of Polymarket and Binance data from my HFT recorder: quotes, feed freshness and features on one clock, with filters and z-scores. Fri, 18 Sep 2026 08:00:00 GMT HFT on Polymarket: Rust, timestamps and the 98% hit rate that wasn't https://ramonfontelles.com/articles/hft-rust https://ramonfontelles.com/articles/hft-rust Recorder-first HFT research on Polymarket: Rust via PyO3, Parquet datasets on local receipt time, LightGBM, and a 98% hit rate that fell to ~55%. Fri, 18 Sep 2026 08:00:00 GMT To predict Polymarket outcomes, I first had to build the dataset https://ramonfontelles.com/articles/prediction-betting https://ramonfontelles.com/articles/prediction-betting Phase 1 of my Polymarket research: a resumable collector over the Gamma, Data and CLOB APIs, holder features, and why collection became the bottleneck. Fri, 18 Sep 2026 08:00:00 GMT A trading bot is infrastructure, not an edge https://ramonfontelles.com/articles/reality-of-bots https://ramonfontelles.com/articles/reality-of-bots Lessons from a live Polymarket bot and an HFT stack: explicit states, fills as proof of execution, WebSockets as truth, API calls off the hot loop. Fri, 18 Sep 2026 08:00:00 GMT Trading 15-minute Polymarket markets until the data said stop https://ramonfontelles.com/articles/trading-15m https://ramonfontelles.com/articles/trading-15m Four entry modes, walk-forward sweeps and a live CLOB bot for 15-minute Polymarket markets, and why I stopped when EV after fees stayed near zero. Fri, 18 Sep 2026 08:00:00 GMT