Karst gas-limit reset — OP Mainnet (055), rotations shift to 056-059

[sbvegan]

Context

Karst (U19) has an op-node/kona-node bug that leaves the effective L2 block gas limit ~55 MGas above the value stored in the SystemConfig after the activation block (see Notion "P/PS: Karst Gas Limit Bug"). The approved mitigation is a per-chain SystemConfig transaction that re-emits the gas ConfigUpdate, resetting the effective gas limit back to the on-chain value.

Mainnet Karst activates 2026-07-08. This task runs after activation.

What this PR does

Inserts the OP Mainnet gas-limit reset as the new 055-gas-limit-op so it executes first among the post-U19 Foundation Upgrade Safe (FUS) tasks — ahead of the signer rotations — and renumbers the previously-merged rotation tasks (#1479) to run after it.

OP Mainnet's SystemConfig is owned by the FUS, so the gas-limit task is rooted there. Running it before the rotations means it is signed by the current owner set, with no dependency on the rotation onboarding.

Task / nonce ordering (FUS = 0x847B…9D92, FOS = 0x9BA6…6b3A)

Task	Safe	nonce	change
053-U19-op-ink-mmz-soneium	FUS	57	—
054-U19-unichain	FUS	58	—
055-gas-limit-op (this PR)	FUS	59	new
056-fus-rotation-1	FUS	60	was 055, nonce 59→60
057-fus-rotation-2	FUS	61	was 056, nonce 60→61
058-fos-rotation-1	FOS	118	was 057, nonce unchanged
059-fos-rotation-2	FOS	119	was 058, nonce unchanged

The FOS nonces are unchanged because the gas-limit task only touches the FUS.

Validation

just simulate-stack eth 059-fos-rotation-2 (full stack) passes end-to-end with no hash mismatches. The regenerated message hashes for the three FUS tasks whose nonce shifted (055, 056, 057) are recorded in their VALIDATION.md files; the FOS task hashes are unchanged. Verify the live FUS/FOS nonces before signing.

Notes

• Only setGasLimit is called (no setEIP1559Params) — the SystemConfigGasLimit template is used since the EIP-1559 params do not need resetting.
• OP Mainnet already has gasLimit = 40000000 on chain; the call is a no-op for storage but re-emits the ConfigUpdate event.

🤖 Generated with Claude Code

[graphite-app]

There is an inconsistency in the nonce before/after values in the State Changes section. The table header rows (lines 87-88, unchanged) say 'Before: 59' and 'After: 60', but the modified detail line (line 90) now says 'incremented from 60 to 61'. This mismatch means the summary rows and the detail row describe different nonce transitions, which will confuse validators trying to verify the state diff. The 'Before' and 'After' summary values should also be updated to 60 and 61 respectively to be consistent with the new nonce ordering.

Suggested change

	- **Before:** `59`
	- **After:** `60`
	- **Summary:** Safe nonce increment.
	- **Detail:** The Safe nonce is incremented from 59 to 60 after executing the transaction.
	- **Detail:** The Safe nonce is incremented from 60 to 61 after executing the transaction.
	- **Before:** `60`
	- **After:** `61`
	- **Summary:** Safe nonce increment.
	- **Detail:** The Safe nonce is incremented from 60 to 61 after executing the transaction.

Spotted by Graphite (based on custom rule: Superchain Ops task/template review)



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[graphite-app]

Similar to the issue in 056-fus-rotation-1/VALIDATION.md, the unchanged summary rows (lines 91-92) still show 'Before: 60' and 'After: 61', but the modified detail line (line 94) now says 'incremented from 61 to 62'. This inconsistency between the summary and detail rows will mislead validators checking the state diff. The 'Before' and 'After' values in the summary should be updated to 61 and 62 to match the new nonce ordering introduced by inserting task 055.

Suggested change

	- **Before:** `60`
	- **After:** `61`
	- **Summary:** Safe nonce increment.
	- **Detail:** The Safe nonce is incremented from 60 to 61 after executing the transaction.
	- **Detail:** The Safe nonce is incremented from 61 to 62 after executing the transaction.
	- **Before:** `61`
	- **After:** `62`
	- **Summary:** Safe nonce increment.
	- **Detail:** The Safe nonce is incremented from 61 to 62 after executing the transaction.

Spotted by Graphite (based on custom rule: Superchain Ops task/template review)



Is this helpful? React 👍 or 👎 to let us know.