EIP-8038State-access gas
RunnableLive on the hosted MCP — free on Amsterdam. Connect an agent and ask.
Website twin: exploration on feelyourprotocol.org
When you SSTORE on Glamsterdam, what are you paying for — touching the slot, changing it, or creating it?
EIP-8038 splits state-touching costs into touch (load), change (write), and create (new leaf). Cold storage access stays 2,100. The write surcharge on an existing slot is STORAGE_WRITE 10,000 (was about 2,800). Creating a slot is still EIP-8037 state gas (about 97,920). EXTCODESIZE / EXTCODECOPY pay an extra warm read.
The MCP server runs your program. It does not ship demo bytecode.
EXTCODESIZE: Run bytecode — call-frame gasUsed.accounts[].storage on 0x00000000000000000000000000000000000000b1.code at to. On Glamsterdam, txStateGas is 0 for an existing slot and about 97,920 for a new one. On bytecode, new-slot Glamsterdam sets stateGasSpilled 97,920 (gasUsed includes the spill).The hosted MCP is live (Connect). Copy a prompt into your agent — each quote is self-contained.
Job
On Glamsterdam, run bytecode that cold SSTOREs 9 into storage slot 1 when slot 1 already holds 7 — prefund slot 1 with 7 on the contract first. How much gas does the call use?
Look forcall gas near 12,106 for the existing-slot write
Agent will likely call run_bytecode
Lesson
Cold SSTORE 9 into storage slot 1 when slot 1 already holds 7 — prefund slot 1 with 7 on the contract, run on Fusaka and on Glamsterdam, and compare call gas.
Look forabout 5,006 vs 12,106
Agent will likely call run_bytecode
Check
On Amsterdam, SSTORE the same value into the same slot twice in one bytecode run — do you pay STORAGE_WRITE twice?
Agent will likely call run_bytecode
Confirm the 8038 catalog row; tools include run_bytecode and run_transaction.
SLOAD / EXTCODESIZE / SSTORE program gas on fusaka then glamsterdam; read gasUsed (and stateGasSpilled on a new slot).
Paid SSTORE code at to when you need txStateGas; seed accounts[].storage for an existing slot.
Seed storage (existing slot) on run_bytecode — put slots on the lab execution account:
{
"bytecode": "<your SSTORE program>",
"accounts": [
{
"address": "0x00000000000000000000000000000000000000b1",
"storage": [{ "slot": "0x03", "value": "0x01" }]
}
],
"fork": { "baseHardfork": "glamsterdam" }
}For paid txStateGas, use run_transaction with code at to and accounts[].storage on that to. Omit storage for a new empty slot. Repeat with "baseHardfork": "fusaka".
Fork caveat
Run the same program twice — fusaka (baseline), then glamsterdam (preview). Glamsterdam already bundles EIP-8038 in EthereumJS v10. Passing eips: [8038] is accepted but is not a pre/post toggle.
Paid gasUsed on a transaction is not a clean 5,006 vs 12,106 — it includes 21,000 intrinsic and EIP-2780 recipient access. Lead with call-frame gasUsed on run_bytecode for the write jump, and txStateGas / stateGasSpilled for create vs change. Cold SLOAD stays 2,103. EXTCODESIZE is about 2,603 vs 3,103.