Methods named prepare* return a serialized prepared flow — an ordered list of unsigned transactions for the user's wallet to sign.
In Celina, a prepared flow is not a workflow engine. It is the object returned by prepare*: primarily steps, an ordered list of unsigned transactions (PreparedTx). The same object is what you:
pass to wagmi / viem one step at a time, or
submit via createAAClient / sendPreparedFlow as sponsored UserOp(s)
prepareSend
transaction
1 (ERC-20 transfer; CELO uses GoldToken)
prepareFx
mentoFx
1–2 (optional approve + swap)
prepareSwap
uniswap
1–3 (optional ERC-20 + Permit2 approve + swap)
prepareSupply
aave
1–2 (optional approve + supply)
prepareWithdraw
aave
1 (withdraw)
prepareClaimUbi
gooddollar
1 (UBI claim)
prepareReserveSwap
gooddollar
1–2 (optional ERC-20 approve + MentoBroker swapIn)
prepareFunction
contract
1 (caller-supplied ABI write)
{
preparedFlow: true,
steps: PreparedTx[],
summary: string, // human-readable label for UI
from: `0x${string}`,
chainId: 42220, // celo.id / CHAIN.id
}The preparedFlow: true discriminator makes it easy to detect prepared flows in chat APIs or JSON responses.
kind
"native" | "erc20" | "contract"
Transaction category
to
`0x${string}`
Target contract or recipient
data
`0x${string}` (optional)
Calldata for contract calls
value
string (optional)
Wei amount as decimal string (JSON-safe)
description
string
Human-readable step label for UI
native — Native-value transfer (to is recipient, value is wei); rare in Celina prepare flows
erc20 — ERC-20 call (to is token contract, data is encoded function). CELO sends use GoldToken (0x471E…) via token duality.
contract — Generic contract call (Aave pool, Mento router, Universal Router, etc.)
When an ERC-20 approval is required before a swap or supply, the SDK returns multiple steps in order:
Sign and confirm each step sequentially. Do not skip or reorder steps.
Call simulatePreparedStep from @andrewkimjoseph/celina-sdk/simulation per step, immediately before sendTransactionAsync — after any prior step is mined. Simulation uses current chain state; simulating step 2 before step 1 confirms falsely fails with insufficient allowance.
Local stdio MCP execute_* tools use the same helper internally before signing with CELO_PRIVATE_KEY.
Those MCP tools sign and broadcast with CELO_PRIVATE_KEY instead of returning unsigned flows to the user.
value fields are decimal strings (not BigInt) so flows serialize cleanly over JSON APIs:
When calling wagmi, convert back to BigInt:
Prepared calldata is tagged with Celina ERC-8021 Schema 0 attribution (appendCelinaCalldataTag) for on-chain identification — sends, Mento FX, Uniswap, Aave, and GoodDollar. You do not need to modify data before passing it to wagmi or to createAAClient().sendPreparedFlow — the same tagged steps work for EOA signing and sponsored UserOps.
createAAClient also accepts optional attributionTags. When set, sendPreparedFlow applies the same ERC-8021 tagger to each step’s data (useful for hand-built steps). When omitted, step data is passed through unchanged. Prefer one consistent tag list per send path — on createCelinaClient for prepare*, or on createAAClient for hand-built flows. Full wire format and check vs verify: On-chain attribution.
See Configuration for the full options table.
Account Abstraction — sponsored UserOps via createAAClient
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const flow = await celina.mentoFx.prepareFx(from, "USDm", "EURm", "100");
// flow.steps might be:
// [0] Approve USDm for Mento FX
// [1] Swap 100 USDm → ~92 EURmimport { serializePreparedFlow } from "@andrewkimjoseph/celina-sdk";
// prepare* methods already return serialized flows
const flow = await celina.transaction.prepareSend(from, to, "CELO", "1");
// flow.steps[0].value === "0" (amount is in transfer calldata)value: step.value ? BigInt(step.value) : undefinedcreateCelinaClient({
attributionTags: ["celo_862c21dd97a7", "celeste_ai"],
});
// ERC-8021 → toDataSuffix(["celina", "celo_862c21dd97a7", "celeste_ai"])