docs: ACCOUNTS.md lists dev balances as ETH, and the amount is off by 100x

[albatrosjj]

…in USDC and correct the amount

Arc has no ETH. Balances match assets/localdev/genesis.json.

Two corrections to ACCOUNTS.md, both verifiable from files already in this
repo.

1. Currency. The balance column reads 10,000 ETH. Arc has no ETH; USDC is
the native gas token. The same file already gets this right further down, where
the MetaMask setup section lists Currency Symbol: USDC, so the document
currently contradicts itself.

2. Amount. The documented figure is 10,000. The localdev genesis allocates
0xd3c21bcecceda1000000 to each of these accounts:

$ python3 -c "print(int('0xd3c21bcecceda1000000', 16) / 10**18)"
1000000.0

Native accounting on Arc is 18 decimals, so that is 1,000,000 USDC, not 10,000.
Source: assets/localdev/genesis.json.

This matters for anyone writing their first test against localdev: they read the
table, assume an ETH-denominated chain with a 10,000 balance, and then hit
confusion when gas comes out of the same asset they are transferring.

Changes:

• Balance column: 10,000 ETH -> 1,000,000 USDC for all ten accounts
• Added one line above the table noting that Arc has no ETH, that USDC is the
  native gas token at 18-decimal precision, and pointing at the genesis file the
  figures come from

Docs only, no code changes.

[osr21]

Disclosure: I'm not affiliated with Circle — an external community contributor, not a maintainer, with no write access. Any review state here carries no merge authority and is advisory only; please defer to Circle maintainers for the binding review.

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Both claims check out. I parsed assets/localdev/genesis.json rather than spot-checking the table — all ten accounts carry exactly 0xd3c21bcecceda1000000:

0xd3c21bcecceda1000000 = 10^24 = 1,000,000 x 10^18

identical across all ten, out of 294 total alloc entries. And the currency point is right: the file contradicts itself today, since the MetaMask section already lists Currency Symbol: USDC. Chain ID 1337 in the doc also matches the genesis config, so the rest of the table is sound and this fix is narrowly scoped. ACCOUNTS.md isn't generated by any script either, so hand-editing is the right mechanism.

Pre-empting the objection your wording will attract

Someone is going to read "1,000,000 USDC at 18-decimal native precision" and object that USDC is a 6-decimal token. You're right, but the repo carries both representations and it's worth knowing why the figure survives either reading:

• Native accounting is 18 decimals — crates/evm/src/log.rs:53 annotates 1_000_000_000_000_000_000 as "1 USDC (18 decimals)".
• The NativeFiatToken ERC-20 is 6 decimals — genesis writes decimals = 6 and symbol USDC into its storage slots (scripts/genesis/NativeFiatToken.ts:173-174).
• The precompile converts between them: "NativeFiatToken uses 6 decimals; the precompile operates in 18-decimal native units" (crates/execution-e2e/tests/e2e/eip7708_precompile.rs:48).

So the native balance is 10^24 base units and the token-interface view of the same holding is 10^12 token units — both are 1,000,000 USDC. The human-readable figure is correct in either view; only the raw integer differs. A parenthetical to that effect would save the next reader the same detour.

The one change I'd ask for before merge

The column is headed Balance (Dev Mode), and the document's opening line scopes itself to "Hardhat, Anvil (Foundry), and Arc local development mode" — with the Compatibility section explicitly ticking Hardhat Network and Anvil.

10,000 ETH is not a fabricated number. It is Anvil's default, and I checked rather than assuming — ran anvil locally (foundry 1.1.0):

(0) 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 (10000.000000000000000000 ETH)
(1) 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 (10000.000000000000000000 ETH)
...
$ cast balance 0xf39Fd6e5... --rpc-url http://localhost:18545
10000000000000000000000

10^22 = 10,000 x 10^18, exactly as documented. So the pre-existing text was correct for two of the three tools on the page and wrong only for the third.

Overwriting the single shared column with Arc-only values fixes Arc and simultaneously makes the table wrong for Anvil and Hardhat — a reader who follows the same page's advice to run anvil will see 10,000 ETH and find the table contradicting their terminal. That's trading one inaccuracy for another rather than removing it.

Two ways to close it properly:

1. Rename the column to Balance (Arc localdev) and leave a short note that Anvil and Hardhat default to 10,000 ETH — smallest change, keeps your diff essentially as-is.
2. Two columns — Anvil / Hardhat and Arc localdev — which is more honest to a document that explicitly serves all three, at the cost of a wider table.

Either works; I'd lean toward (1) since it keeps the diff tight and the accounts table readable.

Minor

The single commit's subject line is malformed — two subjects concatenated without a separator:

Change account balances to USDCdocs: denominate dev account balances in USDC and correct the amount

Worth a reword or squash before merge so the history reads cleanly.

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Genuinely useful catch, and well evidenced — the arithmetic is right, the currency is right, and the self-contradiction with the MetaMask section is real. Leaving this as a comment rather than an approval only because of the Anvil/Hardhat column scoping; fix that and I'd have no reservations.

Method note: the Anvil output and the genesis figures above are executed locally, not recalled — genesis parsed with Python, Anvil run from the environment's foundry 1.1.0. The Rust and Solidity references are source review only, since I have no cargo here.