Pairs trading — market-neutral relative value, and the only strategy that can want to be SHORT. It measures a symbol against a related partner (SPY against VOO, XLE against the benchmark, GLD against TLT) and trades the gap: short the expensive leg, buy the cheap one, close when they converge, and abandon the position outright if the relationship breaks. Its P&L comes from the relationship, not the market direction. Short signals are currently information only — Claude has no verb for going short and the envelope refuses negative targets, so nothing can be shorted until that is deliberately enabled.