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Late Prover Bot

Introduction​

Late Prover Bot monitors the beacon chain for validator exit requests that have passed their required deadline. When a validator fails to exit on time, the bot generates a cryptographic Merkle proof of the delay and submits it to the ValidatorExitDelayVerifier smart contract, enabling penalty enforcement on the responsible node operator.

Requirements​

Hardware​

  • 1-core CPU
  • 8GB RAM

Nodes​

  • Ethereum EL RPC service
  • Ethereum CL API service (Beacon Node)

How to use​

The bot runs as a daemon, continuously processing finalized beacon chain roots. For each root, it discovers ValidatorsExitBusOracle events in the corresponding EL block range, groups validators by their exit deadline slot, and generates proofs for any that have exceeded their deadline. Proofs are submitted in batches via verifyValidatorExitDelay() (or verifyHistoricalValidatorExitDelay() for older roots).

Envs​

Required variables are (mainnet):

VariableDefaultDescription
CHAIN_ID-Ethereum chain ID. 1 for mainnet, 560048 for Hoodi
EL_RPC_URLS-Comma-separated list of EL RPC endpoints
CL_API_URLS-Comma-separated list of CL Beacon API endpoints
LIDO_LOCATOR_ADDRESS-Lido Locator contract address. Addresses for each network can be found here
TX_SIGNER_PRIVATE_KEY-Private key used to sign and submit transactions. Not required when DRY_RUN=true
DRY_RUNfalseIf true, proofs are generated but transactions are not sent

Optional variables can be found here.

Running​

Source Code​

  1. Clone repository and install requirements: 
    git clone git@github.com:lidofinance/late-prover-bot.git
    cd late-prover-bot
  2. Install dependencies: 
    yarn install
    yarn run typechain
    yarn build
  3. Run the bot: 
    yarn run start:prod

Docker​

Docker image can be found here.

Monitoring​

Prometheus metrics and health check are available on the same port:

  • http://localhost:${HTTP_PORT}/metrics
  • http://localhost:${HTTP_PORT}/health