Run validators and relayers

Recoil Link's off-chain side is two programs from the rust/main workspace:

Agent	Job	Count
Validator	Watches one chain's Mailbox and signs a checkpoint for every message sent from it; publishes signatures to storage anyone can read	One per chain, per validator operator
Relayer	Reads signatures, delivers prepaid messages to their destinations, pays destination gas	One or more; delivery is permissionless

Recoil Labs runs both today. The full production setup (GCP, Cloud KMS keys, GCS signature storage, alerts) is in docs/recoil-link/production-deployment.md.

Running locally against the testnets

cd recoil-link/rust/main && cargo build --release --bin validator --bin relayer
cd ../.. && rlink registry agent-config --chains sepolia basesepolia --out configs/recoil-link/testnet/agent-config.json
scripts/recoil-link/testnet/validator.sh sepolia     # one per chain
scripts/recoil-link/testnet/relayer.sh

The scripts read keys from ~/.recoil-link/keys/ and run each agent from its own working directory, so only Recoil Link's config is loaded.

Rules that matter

• Never run the agents from rust/main or in an image that copies rust/main/config: that directory holds Hyperlane's chain configs, and the agents load every JSON in ./config.
• Validators need private RPCs. They refuse public endpoints unless allowPublicRpcs is set.
• One instance per relayer key. Two relayers sharing a key race each other's nonces.
• Keys: hex keys for local testing; Cloud KMS (type: gcp) or AWS KMS in production.

Becoming a validator

Adding a validator means adding its address to each chain's ISM, which only the contract owner (the treasury Safe) can do. Contact Recoil Labs if you want to run one; Operators covers what's expected of a validator operator.