Reference

Transaction Classification Glossary

Every class ID TrueBasis assigns — what it means structurally, how it was detected, and CPA review notes for professional follow-up.

Not sure how to use these classifications? Read the results guide for a full walkthrough of your audit output.

Trading & Swaps

SWAP
High Confidence Trading

Token Swap

You exchanged one token for another through a decentralized exchange. TrueBasis detected this by identifying a call to a known DEX router — Uniswap V3, 1inch, Curve, or a V2 fork — combined with a token-in / token-out transfer pattern. The specific protocol is recorded in the audit evidence.

CPA review note: Structurally, one token was sent to a DEX router and a different token was received. Your CPA should assess the treatment of this exchange.
ROUTER_SWAP
High Confidence Trading

Router Swap (Uniswap V2)

A token swap routed through a hardcoded Uniswap V2 router address. Functionally identical to SWAP — the distinction is how TrueBasis detected it. ROUTER_SWAP is used when the contract address itself matches a known router, rather than a method selector match.

CPA review note: Structurally the same pattern as SWAP: router involvement with token-in and token-out transfers. Your CPA should assess the treatment of this exchange.
APPROVAL
High Confidence Trading

Token Approval

You granted a smart contract permission to spend tokens from your wallet up to a specified amount. This is a required step before most DEX trades, DeFi deposits, and NFT marketplace listings. No tokens actually moved in this transaction — only permission was granted.

CPA review note: Structurally, no tokens moved—only an approval to spend was granted. Your CPA should review whether any fees paid in this transaction are relevant to document.

DeFi — Lending, Vaults & Liquidity

BORROW
High Confidence DeFi

Loan Initiated

You borrowed assets from a lending protocol — Aave V2/V3 or Compound V2/V3. TrueBasis detected this via the protocol's borrow method selector and confirmed the receiving address. The borrowed amount and protocol are recorded in the audit evidence.

CPA review note: Structurally, assets were received from a lending protocol. TrueBasis flags open BORROW positions without a matching REPAY so your CPA can review the full position lifecycle.
REPAY
High Confidence DeFi

Loan Repayment

You repaid borrowed assets to a lending protocol. TrueBasis links REPAY transactions to their corresponding BORROW in the session engine, so your CPA can see the full lifecycle of a lending position.

CPA review note: Structurally, assets were returned to a lending protocol. Your CPA should review interest and fee components in context.
VAULT_DEPOSIT_MINT
High Confidence DeFi

Vault Deposit

You deposited tokens into a yield vault or protocol and received a receipt token (sometimes called a share token or LP token) in return. Common in ERC-4626 vaults, Yearn, and similar yield aggregators. The receipt token represents your claim on the underlying deposited assets.

CPA review note: Structurally, tokens were deposited and receipt (share) tokens were received. Your CPA should assess the treatment of this exchange of tokens for the specific protocol.
VAULT_WITHDRAW_BURN
High Confidence DeFi

Vault Withdrawal

You redeemed your receipt/share tokens and received the underlying assets back from a vault. TrueBasis detects this by identifying the token burn event paired with an outgoing asset transfer from the vault contract.

CPA review note: Structurally, receipt tokens were redeemed and underlying assets left the vault. Your CPA should compare amounts to the original deposit and review any yield or fee components.
LP_ADD
Medium Confidence DeFi

Liquidity Added

You deposited two tokens into a liquidity pool and received LP tokens representing your share of the pool. Common on Uniswap, Curve, and their forks. TrueBasis detects this via the dual-token deposit pattern and LP token mint event.

CPA review note: Structurally, two tokens were deposited and LP tokens were minted. Your CPA should assess the treatment of this exchange and of any later redemption.
LP_REMOVE
Medium Confidence DeFi

Liquidity Removed

You redeemed LP tokens and withdrew your share of a liquidity pool. You may receive a different ratio of the two tokens than you originally deposited due to impermanent loss and fee accrual.

CPA review note: Structurally, LP tokens were burned and the underlying assets returned (possibly in a different ratio than deposited). Your CPA should compare inflows and outflows to the pool.
REWARDS_CLAIM
High Confidence DeFi

Rewards Claim

You claimed protocol rewards or a merkle-tree distribution — staking rewards, liquidity mining emissions, governance token distributions, or similar. TrueBasis detects this via the claim() method selector or known distributor contract addresses.

CPA review note: Structurally, tokens were received from a claim or distributor contract. This pattern is often mislabeled in third-party tools; your CPA should verify how the receipt should be recorded.
PROTOCOL_DEPOSIT
Medium Confidence DeFi

Protocol Deposit

Tokens were sent to a known protocol contract, but the interaction did not match a specific known pattern like a vault deposit or liquidity provision. Used when TrueBasis can confirm the destination is a legitimate protocol but cannot determine the exact intent.

CPA review note: Structurally, tokens were sent to a known protocol contract without a more specific pattern match. Your CPA should review the contract and transaction details.
PAYABLE_CONTRACT_ETH_DEPOSIT
Medium Confidence DeFi

ETH Sent to Contract

ETH was sent directly to a payable smart contract with no calldata — meaning no specific function was called. This often happens with staking contracts, simple deposit mechanisms, or older protocol designs that accept plain ETH transfers.

CPA review note: Structurally, ETH was sent to a payable contract with no calldata. Your CPA should determine what the contract did with the funds.

Transfers & Bridges

EOA_TRANSFER
High Confidence Transfer

Wallet-to-Wallet Transfer

A simple transfer between two externally-owned addresses (regular wallets, not smart contracts). No protocol was involved. This is the most basic transaction type on any blockchain.

CPA review note: Structurally, this is a simple transfer between two externally owned addresses. If both are the client's wallets, providing owned_addresses.json lets TrueBasis confirm self-transfers automatically; otherwise your CPA should verify counterparty ownership.
SELF_TRANSFER_CONFIRMED
High Confidence Transfer

Self-Transfer (Confirmed)

Funds moved between two addresses you confirmed you own. TrueBasis verified this because both addresses appeared in your owned_addresses.json file.

CPA review note: Structurally confirmed as a move between addresses listed in owned_addresses.json. Your CPA should still keep a record of wallet addresses on file.
SELF_TRANSFER_CANDIDATE
Medium Confidence Transfer

Self-Transfer (Unconfirmed)

This transaction went to an address that appeared in your audit's wallet set, but ownership was not confirmed via owned_addresses.json. TrueBasis suspects this is a self-transfer but cannot confirm it structurally.

CPA review note: Structurally, ownership of the destination could not be confirmed. Provide owned_addresses.json on a future audit to allow automatic confirmation if appropriate.
BRIDGE_TRANSFER
High Confidence Transfer

Bridge Transfer

You sent assets to a known cross-chain bridge deposit contract — moving tokens from one blockchain to another (e.g. Ethereum to Arbitrum). TrueBasis confirmed the destination address matches a known bridge contract.

CPA review note: Structurally, assets were sent to a known bridge deposit contract. Mechanics vary by bridge (burn/mint, lock/mint, etc.); your CPA should assess the full flow.
BRIDGE_TRANSFER_CONFIRMED
High Confidence Transfer

Bridge Transfer (Matched)

TrueBasis matched this bridge transaction to its counterpart on the destination chain — same recipient, same token, same amount (within 1%), within 24 hours, on a different chain. Full round-trip bridge confirmed. Risk level is set to NONE for matched bridge pairs.

CPA review note: Structurally, TrueBasis matched deposit and destination-chain receipt (same recipient, token, and amount within tolerance). Your CPA should still validate that the pattern matches the client's facts.
CONTRACT_TRANSFER
Low Confidence Transfer

Contract Transfer

A token transfer to a smart contract that does not match any known protocol pattern. The destination is a contract, but TrueBasis could not determine what it does. This is a catch-all for interactions with contracts not yet in the protocol registry.

CPA review note: Structurally, tokens moved to a contract TrueBasis could not classify. Your CPA should investigate the destination contract to determine what occurred.

NFT

NFT_MINT
Medium Confidence NFT

NFT Mint

You minted a non-fungible token directly from a contract. TrueBasis identifies this by detecting a transfer from the zero address (the standard on-chain signal for a mint event) with a non-fungible token amount.

CPA review note: Structurally, an NFT was minted from the zero address and value may have been paid in the same transaction. Your CPA should document what was paid and received.
NFT_SALE
Medium Confidence NFT

NFT Sale

You bought or sold an NFT through a marketplace. TrueBasis detects this via known marketplace contracts — Seaport (OpenSea), Blur, and others — combined with a payment flow (ETH or token moving in exchange for an NFT).

CPA review note: Structurally, an NFT and payment (ETH or tokens) moved through a known marketplace flow. Your CPA should assess the treatment of both legs of the exchange.

Risk Flags & Unresolved

AIRDROP_RECEIVED
Low Confidence Risk

Airdrop Received

Tokens arrived in your wallet without you initiating a transaction — an unsolicited incoming transfer. TrueBasis checks the token contract's age and verification status to help distinguish legitimate airdrops from dust attacks or spam tokens. Unverified or very new contracts increase risk level.

CPA review note: Structurally, tokens arrived without an outgoing transaction from this wallet. Contract age and verification inform risk; your CPA should review whether the receipt is material and how to document it.
MEV_VICTIM
Medium Confidence Risk

MEV Sandwich Attack

TrueBasis detected that your swap was sandwiched by a MEV (Maximal Extractable Value) bot on Ethereum mainnet. A bot placed a transaction immediately before and after yours in the same block, manipulating the price to extract value from your trade. You received fewer tokens than you should have at the quoted price.

CPA review note: Structurally, a swap occurred with sandwich activity detected—the executed price was worse than the quoted path. Your CPA should review quantities received versus expected for documentation.
UNCLASSIFIED
Low Confidence Risk

Unclassified

TrueBasis could not match this transaction to any known pattern. The contract or method selector is not in the protocol registry, and the transfer pattern did not match any structural heuristic. These transactions appear in review.csv and require manual investigation.

CPA review note: TrueBasis could not assign a structural class. Your CPA should investigate the transaction on a block explorer to determine what occurred—this is a structural gap, not a determination of how it should be recorded.

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