thought_epoch

The thought_epoch program is the on-chain anchor for Lucid’s receipt verification system. It stores Merkle Mountain Range (MMR) roots on Solana, making AI interaction history permanently verifiable. Program ID (devnet): 8QXiFjguJT4PLVzH6BYNMHXZ3eLRaoF8cwx23EBc44Q6

Instructions

Instruction	Description
`init_epoch`	Create a new epoch record PDA (first time only)
`commit_epoch`	Update an existing epoch record with a new MMR root
`init_epochs`	Create a new batch record for up to 16 roots
`commit_epochs`	Update an existing batch record with new roots
`init_epoch_v2`	Create a v2 record with extended metadata
`commit_epoch_v2`	Update a v2 record with new root and metadata

Account Structures

EpochRecord

Stores a single MMR root.

Field	Type	Description
`merkle_root`	`[u8; 32]`	SHA-256 MMR root hash
`authority`	`Pubkey`	Signer authorized to update

PDA seeds: ["epoch", authority]

EpochRecordBatch

Stores up to 16 MMR roots in a single account.

Field	Type	Description
`roots`	`Vec<[u8; 32]>`	Up to 16 MMR root hashes
`authority`	`Pubkey`	Signer authorized to update

PDA seeds: ["epochs", authority]

EpochRecordV2

Extended epoch record with metadata for richer on-chain queries.

Field	Type	Description
`merkle_root`	`[u8; 32]`	SHA-256 MMR root hash
`authority`	`Pubkey`	Signer authorized to update
`epoch_id`	`u64`	Sequential epoch identifier
`leaf_count`	`u64`	Number of receipts in this epoch
`timestamp`	`i64`	Unix timestamp of epoch finalization
`mmr_size`	`u64`	Total MMR size at finalization

PDA seeds: ["epoch_v2", authority]

Usage

The offchain engine finalizes an epoch when either threshold is met (100+ receipts or 1+ hour). It then calls commit_epoch_v2 to anchor the root:

import { Program } from '@coral-xyz/anchor';

await program.methods
  .commitEpochV2(
    root,       // [u8; 32] MMR root
    epochId,    // u64
    leafCount,  // u64
    timestamp,  // i64
    mmrSize     // u64
  )
  .accounts({
    authority: wallet.publicKey,
    epochRecordV2: epochPda,
  })
  .rpc();

Gas Costs

Single commit: 5 LUCID (mGas)
Batch commit (up to 16 roots): 7 LUCID total (2 base + 5 mGas)

Errors

Error	Description
`BatchTooLarge`	Batch size exceeds MAX_BATCH (16)

Solana Programs

EVM Contracts

thought_epoch

Instructions

Account Structures

EpochRecord

EpochRecordBatch

EpochRecordV2

Usage

Gas Costs

Errors

​Instructions

​Account Structures

​EpochRecord

​EpochRecordBatch

​EpochRecordV2

​Usage

​Gas Costs

​Errors

Instructions

Account Structures

EpochRecord

EpochRecordBatch

EpochRecordV2

Usage

Gas Costs

Errors