docs: live SSTORE gas widget backed by a verified on-chain probe

[alexander-sei]

What

Adds a live widget to the SSTORE Gas Cost section of evm/differences-with-ethereum that reads the storage-write gas cost directly from the chain, so it can never drift from reality the way a hardcoded number can. This is the self-maintaining answer to the staleness problem behind #34.

How it works

snippets/sstore-gas-live.jsx calls SstoreGasProbe via eth_call (read-only — state is discarded, no gas spent). The contract measures a throwaway SSTORE with the GAS opcode, so it returns whatever the governance parameter KeySeiSstoreSetGasEIP2200 is set to right now.

It surfaces two numbers, with a mainnet/testnet toggle:

• SSTORE_SET parameter ≈ 72,000 (the governance value, Prop #109)
• Cold first write ≈ 74,100 (= param + EIP-2929 cold access)

Verified on-chain contract

The contract source lives on-chain via Sourcify, not in this repo. Both deployments are exact_match (creation + runtime) and visible on Seiscan:

Network	Address
Mainnet (pacific-1 / 1329)	0xeeB428bcf499D0A1c401f123F64BFf754a5de57A
Testnet (atlantic-2 / 1328)	0xE5A35b2457E1C3cfF2F6527fAA32DE0B2a8e28E0

Devs can also call it directly: cast call <addr> "coldWriteCost()(uint256)" --rpc-url <sei rpc>.

Verification done

• mint dev compiles the page and SSR-renders the widget (no errors).
• The exact client fetch+parse path returns 72,008 / 74,107 against the deployed contracts on both networks.
• Contract logic cross-checked vs. the empirical eth_estimateGas probe from docs: reconcile SSTORE gas to 72,000 (same on both networks, Prop #109) #34 (72,000 + 2,100 cold).

Scope

• Stacked on docs: reconcile SSTORE gas to 72,000 (same on both networks, Prop #109) #34 (docs/reconcile-sstore-gas) so the widget sits with the corrected SSTORE prose. Retarget to main once docs: reconcile SSTORE gas to 72,000 (same on both networks, Prop #109) #34 merges.
• Only two files: the widget snippet + the doc insertion. No Agent Skills registry artifacts; no Solidity committed to the repo (it's on Sourcify).

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Documentation-only change with optional public RPC calls from the browser; no chain, auth, or backend logic is modified.

Overview
The SSTORE Gas Cost section in evm/differences-with-ethereum.mdx now embeds a live on-chain widget instead of relying only on static copy, so governance-tuned SSTORE costs stay accurate when parameters change.

New snippet SstoreGasLive (snippets/sstore-gas-live.jsx) queries verified SstoreGasProbe contracts on mainnet and testnet with read-only eth_call, shows SSTORE_SET parameter and cold first write gas, and lets readers switch networks. The doc imports the component and adds a short lead-in that values are read live from Sei EVM.

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Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

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Stale RPC responses race

Medium Severity

Switching Mainnet/Testnet starts a new load without invalidating earlier eth_call requests. If an older fetch finishes after a newer one, setData and setLoading still run, so the widget can show one network’s gas values while the other tab and footer labels are selected.

 

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