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SPL transfer and Jupiter swap fail for fractional amounts like 2.01

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@sebxt is already working on this.

Since Oct 18, 2026.

  • #1575 by @sebxt — open

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
35/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
typescript
Domain
api, backend

Research direction

Start with typescript/agentkit/src/action-providers/spl/splActionProvider.ts and typescript/agentkit/src/action-providers/jupiter/jupiterActionProvider.ts, where both actions scale the amount by the mint decimals. Check the tests around SPL transfers and Jupiter quote requests, then verify that 2.01 USDC becomes the integer base unit amount 2010000 for both actions. An open linked pull request already addresses this issue.

Written by the indexing model from the issue text.

Description

What happens

SplActionProvider.transfer converts the whole unit amount to base units with plain floating point math and then calls BigInt on the result:

const adjustedAmount = args.amount * Math.pow(10, mintInfo.decimals);
...
if (sourceAccount.amount < BigInt(adjustedAmount)) {

For many ordinary amounts the product is not an integer. With a 6 decimal mint (USDC), 2.01 * 10 ** 6 is 2009999.9999999998, so BigInt throws and the action returns:

Error transferring SPL tokens: RangeError: The number 2009999.9999999998 cannot be converted to a BigInt because it is not an integer

Other examples with 6 decimals: 2.03, 2.05, 4.02. With 9 decimals: 1.07, 2.01.

JupiterActionProvider.swap uses the same conversion (args.amount * 10 ** mintInfo.decimals) and passes the fractional value straight to quoteGet as amount, so the quote request carries amount=2009999.9999999998 instead of the integer base unit amount the Jupiter API expects.

What should happen

Both actions should convert the amount to an integer number of base units (2.01 USDC is 2010000) and proceed.

Minimal repro

const provider = new SplActionProvider();
// mint with 6 decimals, sender holds enough balance
await provider.transfer(wallet, { recipient, mintAddress, amount: 2.01 });
// => "Error transferring SPL tokens: RangeError: The number 2009999.9999999998 cannot be converted to a BigInt because it is not an integer"

Or directly: BigInt(2.01 * Math.pow(10, 6)) throws.

Root cause

typescript/agentkit/src/action-providers/spl/splActionProvider.ts and typescript/agentkit/src/action-providers/jupiter/jupiterActionProvider.ts scale a JS number by 10 ** decimals without rounding. Binary floating point cannot represent most decimal fractions exactly, so the product is often a hair above or below the intended integer.

Dominant language
TypeScript
Stars
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Forks
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Getting set up

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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