Solana priority-fee tip for agents that build transactions: p25/p50/p75/p90/max and non-zero percentiles of getRecentPrioritizationFees over the last ~150 slots, plus low/medium/high/veryHigh micro-lamport suggestions, refreshed every 2 s. Long-poll with ?since=<seq>&wait=25. Prepaid meter price $0.0002/call (packs at /v1/meter); SSE at /v1/stream/tips.