Sprout is a play-to-plant idle game built on Solana. Players grow virtual trees, earn LEAF tokens through daily nurturing, and a portion of every in-game SOL purchase is routed on-chain to a planting treasury that funds real-world tree planting through One Tree Planted, with weekly Solscan-verifiable transaction proofs published in a public transparency channel. The economy is closed-loop: LEAF spent on tree purchases and upgrades is transferred to a yield pool that pays player withdrawals. LEAF is a Solana SPL token. Total supply is permanently capped at 1,000,000 LEAF. Mint authority is revoked on-chain, freeze authority is revoked, and there is no team allocation, no pre-mine, and no airdrop.