Domain playbook for optimization missions — any task whose goal is to move a metric: performance, latency, throughput, memory, cost, score, quality, compression, ranking, solver, model/eval, and similar metric-improvement work. Defines how to think about and run an optimization mission: establishing the ground truth, trusting the measurement, profiling to the dominant cost, estimating the ceiling, generating and pruning disposable hypotheses, exploring cheaply before verifying expensively, guarding against metric gaming and overfitting, reasoning about correctness and trade-offs, and stopping on evidence.