Tuktuk

TukTuk Assignment

Assignment

Implement the scheduler and the cron job in any of the previous challenges.

Implementation

TukTuk is integrated into the escrow-litesvm program as an auto-refund scheduler. When a maker creates an escrow, they can schedule a TukTuk task that automatically refunds the escrowed tokens if no taker fulfills the trade by the expiry time.

New Instructions

auto_refund — Permissionless refund executed by TukTuk crankers

• No maker signature required (TukTuk crankers call this on behalf of the maker)
• Graceful no-op if the escrow was already taken or manually refunded
• Transfers vault tokens back to maker and closes both vault and escrow accounts

schedule_refund — Maker-signed instruction to schedule the auto-refund

• CPIs into TukTuk's queue_task_v0 to register a time-triggered task
• Compiles the auto_refund instruction into TukTuk's transaction format
• Accepts an expiry_timestamp to set when the refund should execute

Source Files

• programs/anchor-escrow/src/instructions/auto_refund.rs
• programs/anchor-escrow/src/instructions/schedule_refund.rs

Tests

All 7 tests pass including 2 new auto-refund tests:

• test_auto_refund_success — make → auto_refund → verify tokens returned, vault + escrow closed
• test_auto_refund_already_taken_noop — make → take → auto_refund → verify graceful no-op

cd ../escrow-litesvm
cargo test -p anchor-escrow -- --nocapture

Resources

• TukTuk Docs
• Helper Repo
• Cron schedule expressions