DX report — two days from zero to a verified factory on Arc mainnet, and the six things that cost time

[edycutjong]

Everything protocol-level worked first try: unchanged Solidity/Foundry (solc 0.8.30, osaka), USDC as native gas,
CREATE2 + constructor-SELFDESTRUCT moving a pre-funded balance exactly as evm-differences.md documents, and CCTP FAST +
the Forwarding Service landing the first USDC in one call. The friction was all tooling and early-mainnet:

1. First USDC on Arc is a chicken-and-egg: the CCTP receiveMessage mint is paid in USDC on Arc, which a fresh wallet
   has none of. useForwarder: true solves it — but that is the answer to the first question every new builder has, and it
   is not where they look first (the bridge guide).
2. forge script with a CREATE2 salt fails "Chain 5042 not supported" — Foundry's deterministic-deployer path guards on
   a known-chains list. Workaround: the Arachnid factory directly. A note in the Foundry section would save an hour.
3. msg.sender inside startBroadcast is Foundry's default sender, not the keystore. A probe sent funds to the wrong
   address this way. Pass owner/treasury explicitly — worth a warning in the deploy docs.
4. eth_getLogs is capped at 10,000 blocks per call (9,999-block span answers; 10,000 → -32012), and sustained rate
   on the public RPC is ≈0.5 getLogs/s (1/s is refused indefinitely with -32005; 1 per 2 s always succeeds — 40/40 each).
   Both numbers belong on the RPC page.
5. rpc-endpoints.md says mainnet RPC/explorer are "permissioned"; both answer anonymously. A backend-less page depends
   on which of those is the commitment.
6. Docs address drift: integrate_exchanges_cctp-bridging.md names MessageTransmitter 0xE737e5cE… (no code on mainnet);
   the live one is 0x81D40F21… per the contract-addresses reference.

Full report with dates and tx hashes: https://github.com/edycutjong/pigeonhole/blob/main/docs/DX-REPORT.md