EIP complexity assessment

EIP-8024: Backward compatible SWAPN, DUPN, EXCHANGE

Assessed in Amsterdam / Glamsterdam. The score describes the EIP text available at the assessment cutoff, not the EIP as it stands today.

RetrospectiveAmsterdam / GlamsterdamAssessment cutoff 2025-10-29Included by cutoffLayers: execution

LLM Completescore 11

Human Completescore 6 · Checklist revision 1· merged checklist

LLM · Checklist revision 32026-10-08 · Opus 5.5 · primary · 11 Human · Checklist revision 1Complete · 6 CompareHuman vs LLM · shared criteria

Evaluated on: 2026-10-08 · Spec revision: 2025-09-17 · 28578c7ba0

Scope at the cutoff. EIP-8024, at this revision, adds three legacy EVM instructions: DUPN (0xe6), SWAPN (0xe7) and EXCHANGE (0xe8). Each takes a 1-byte immediate and costs a constant 3 gas. DUPN and SWAPN reach stack items 17–235, and EXCHANGE swaps defined (n, m) pairs within the top 30 items. The immediate is decoded by decode_single or decode_pair. Immediates in the ranges 91–127 (DUPN/SWAPN) and 80–127 (EXCHANGE) cause a halt that consumes all gas. These ranges are excluded so that JUMPDEST analysis stays unchanged and no existing jump target is created or removed.

11LowLow

Evaluator: LLMChecklist v3
Confidence: High
Under-specified at assessment cutoff: Yes — 2 criteria affected
Plausible range: 11–12 (Low–Medium)
Assessment cutoff: 2025-10-29 · EIP revision 28578c7ba0 (2025-09-17)

Score bands · Checklist revision 3

Low <12
Medium 12–22
High ≥23

28 criteria scored 0–3 (4 in exceptional cases; cross-EIP interactions is uncapped); nominal maximum 84.

Complexity profile

Each segment is one criterion's contribution to the LLM total. Hover or focus a segment for its score and rationale.

Under-specified at assessment cutoff: Yes

The EIP text available at the assessment cutoff left material behavior unresolved. The affected criteria and the plausible total range record that uncertainty.

Why: There are minor, localized omissions: stack underflow/overflow handling, how an immediate past the end of the code is read, and the use of the word "revert" alongside "consuming all gas". General EVM conventions resolve each of these to a single outcome.

Plausible total

11–12
recorded score 11 · plausible tiers Low, Medium

Affected criteria (2)

Edge/boundary conditions (2)
Unspecified behavior requiring cross-client consensus (1)

Unresolved questions at the cutoff (3)

What happens when the opcode is the last byte of the code: is the missing immediate read as 0 (DUPN 17, and so on)?
Is the invalid-immediate failure an exceptional halt, or a REVERT with return data, given that it consumes all gas?
Stack underflow when n exceeds the stack height, and DUPN overflow at 1024 items, are not stated explicitly.

Notable ambiguities noted by the assessor (3)

The word "revert" is used for invalid immediates while also requiring all gas to be consumed.
Reading an immediate at code[pc+1] beyond the end of the code is not specified.
Stack underflow/overflow conditions are not stated in the formal steps.

Criterion breakdown

EIP-8024 Amsterdam / Glamsterdam: LLM criterion scores and rationale
Criterion	Score	Why this score	Evidence / uncertainty
Added opcodes	3	Multiple instructions are introduced, and all of them are complex because they carry immediate data. This is level 3.	eip.md · Specification — "We introduce three new instructions" DUPN, SWAPN and EXCHANGE are new instructions. eip.md · Specification — "Let x = code[pc + 1]" Each instruction has immediate data, operand-dependent stack access and an invalid-immediate halt. Confidence: High
Edge/boundary conditionsUnder-specified	2	Several independent boundary-sensitive mechanisms are introduced: the invalid-immediate ranges for each opcode, the piecewise decode branches, stack-depth reachability (n relative to stack height, and DUPN at 1024 items), and the JUMPDEST/PUSH compatibility boundary. None forms an elevated matrix whose combinations cannot be tested separately, so this is level 2.	eip.md · Specification — "If 90 < x < 128 revert" / "If 79 < x < 128 revert" Each opcode has a range of invalid immediates with boundaries at 90/91, 127/128 and 79/80. eip.md · Specification — decode_single / decode_pair The piecewise mappings have branch boundaries (x≤90 vs ≥128; the q<r branch; k=x vs x−48). eip.md · Rationale / Disallowed immediate range The JUMPDEST and PUSH bytes used as immediates mark a compatibility boundary. Confidence: Medium Uncertainty: Stack underflow/overflow and an immediate past the end of the code are not stated explicitly, though general EVM rules imply exceptional halts.
Patterns affecting pre-existing tests	1	Baseline tests that treat 0xe6–0xe8 as undefined and expect an exceptional halt must now expect execution when the immediate is valid. That rework is confined to a few cases in the undefined-opcode family, so this is level 1.	eip.md · Specification — "DUPN (0xe6) SWAPN (0xe7) EXCHANGE (0xe8)" Previously undefined opcode bytes now execute when followed by a valid immediate. eip.md · Backwards Compatibility Only contracts that attempt to execute these opcodes are affected. Confidence: Medium Uncertainty: No test suite was supplied, so the number of affected undefined-opcode tests is estimated.
New test-framework primitives	1	The framework's opcode and bytecode builder needs a local extension to encode the operand-to-immediate mapping, and to emit raw invalid immediates. No new abstraction is required, so this is level 1.	eip.md · Specification — encode_single / encode_pair Assemblers must emit an encoded 1-byte immediate after each opcode. eip.md · Test Cases / Assembly/Disassembly Bytecode must be assembled, and disassembled, using the immediate encoding, including the invalid-immediate forms. Confidence: Medium Uncertainty: Existing support for opcodes with immediates is assumed to extend; actual helper availability was not supplied.
Security risks	1	The new security condition, preserving jump-target analysis and halting on invalid immediates, can be checked locally within the EVM interpreter and its jumpdest analysis. This is level 1.	eip.md · Rationale / Disallowed immediate range No JUMPDEST may be created or removed in any bytecode by introducing these instructions. eip.md · Specification — "JUMPDEST analysis is unchanged" Clients must not treat the immediate byte as skipped in jump-destination analysis. Confidence: Medium
Performance risks	1	Component benchmarks of deep DUPN, SWAPN and EXCHANGE are enough to confirm that 3 gas is adequate, including immediate decoding at stack depths up to 235. No end-to-end performance assumptions change, so this is level 1.	eip.md · Rationale / Gas cost The constant 3 gas assumes the operations are pointer swaps with negligible decoding cost. eip.md · Security Considerations The stack is fixed at 1024 items and kept in memory. Confidence: Medium Uncertainty: This could be 0 if benchmarking is considered unnecessary given the parity with DUP/SWAP.
Cross-EIP interactions	1	Only local compatibility checks with existing opcode and jump-analysis behavior are needed. The target's behavior can otherwise be tested on its own, so this is level 1.	eip.md · Test Cases — "e65f is [INVALID_DUPN, PUSH0]" Invalid-immediate handling interacts with the PUSH0 byte and with PUSH1–PUSH32 data. eip.md · Rationale / Disallowed immediate range Compatibility with JUMPDEST analysis and PUSH data must be preserved. Confidence: Medium Uncertainty: The candidate list is empty, so the interactions are recorded without EIP numbers.
Unspecified behavior requiring cross-client consensusUnder-specified	1	Several localized details are omitted, but general EVM rules support one intended outcome for each: exceptional halt on underflow/overflow, and zero-padded code for a missing immediate. Because every failure path consumes all gas, the order of checks is not observable. This is level 1.	eip.md · Specification — "revert, consuming all gas" The text says "revert" while also requiring all gas to be consumed, which implies an exceptional halt rather than a REVERT. eip.md · Specification — DUPN/SWAPN/EXCHANGE steps Stack underflow (n beyond stack height), DUPN overflow at 1024, and an immediate beyond the end of the code are not addressed explicitly. Confidence: Medium Uncertainty: If clients disagree on how to read an immediate past the end of the code, or on the meaning of "revert", this would rise to level 2.

Show 20 zero-score criteria

Zero-score criteria (Checklist revision 3)
Criterion	Why this score	Evidence / uncertainty
Modified opcodes	Only previously undefined bytes gain meaning, which is counted under Added opcodes. No existing instruction's semantics or availability changes.	eip.md · Specification — "JUMPDEST analysis is unchanged" Existing instructions and jump-target analysis are unchanged. eip.md · Backwards Compatibility Contracts that never execute the new opcodes are unaffected.
Added precompiles	None added.	eip.md · Specification No precompile is introduced.
Modified precompiles	None modified.	eip.md · Specification No precompile is changed.
Added system contracts	None added.	eip.md · Specification No system contract is introduced.
Modified system contracts	None modified.	eip.md · Specification No system contract is referenced.
EVM Gas rule changes	The new instructions only have constant per-opcode costs. No accounting rule or baseline gas result changes, so this is level 0.	eip.md · Specification — "Charge 3 gas." Each new opcode charges a constant 3 gas through the ordinary static-cost path. eip.md · Rationale / Gas cost The cost matches the existing DUP/SWAP instructions.
State-access ordering within opcode execution	No state is accessed and no instruction's access ordering changes.	eip.md · Specification The instructions only touch the stack and code bytes; they access no state.
Blob gas accounting changes	No blob-gas accounting changes.	eip.md · Specification Nothing relates to blobs.
State gas accounting changes	No state-gas accounting changes.	eip.md · Specification Stack-only instructions with no state writes.
New EVM gas refund	No new refund mechanism.	eip.md · Specification No refund is mentioned.
New transaction types	None introduced.	eip.md · Specification No transaction type is introduced.
New or modified transaction validity mechanisms	No transaction-validity or intrinsic-gas changes.	eip.md · Specification Only execution-time opcode semantics change.
New block / header fields	None added.	eip.md · Specification No header fields.
Encoding changes (RLP/SSZ)	The immediate encoding is part of contract bytecode, not a protocol serialization schema.	eip.md · Specification Only the bytecode immediate encoding is defined; no serialized EL object changes.
Block syncing changes	No block RLP or structural validation changes.	eip.md · Specification No block structure or decoding changes.
New fork activation mechanism	No activation-specific state transition is required.	eip.md · Backwards Compatibility No state migration is needed; this is only a rule selection at the fork.
Engine API changes	No Engine API changes.	eip.md · Specification Only EVM execution changes.
Transition-tool interface changes	The transition tool's interface does not change.	eip.md · Specification Only EVM execution semantics change; no new inputs or outputs.
New invariant on pre-existing tests	Baseline tests need no new assertion.	eip.md · Specification The EIP adds no new outputs such as logs, header fields or receipt fields.
Cryptography	No cryptography is added or changed.	eip.md · Specification No cryptographic operations.

Assessment provenance

Assessed EIP revision: ethereum/EIPs@28578c7ba0 EIPS/eip-8024.md committed 2025-09-17 · information cutoff 2025-10-29T02:00:31Z
Current master · File history · blob b519c1ce60 · sha256 c4de111b08cf
Rubric: Checklist revision 3 · ethspecs/pm@fe2f793b03
Evaluator: Opus 5.5 (claude-opus-5-5) at high effort, one tool-less call per EIP · isolation bubblewrap_claude_p_no_tools_v1
Source record: Frozen research record research/tasks/10-opus-v3-reassessment/retrospective/outputs/assessments/amsterdam/eip-8024.yaml · sha256 5efa5f1d1251

Evaluated on: Not recorded · Spec revision: 2025-11-04 · db5c483ea1

6LowLow

Evaluator: HumanChecklist v1
Confidence: Not recorded
Under-specified at assessment cutoff: Not recorded in the checklist
Checklist published: 2025-11-05 · EIP at db5c483ea1
Source: merged ethspecs/pm checklist

Score bands · Checklist revision 1

Low <10
Medium 10–19
High ≥20

24 criteria scored 0–3 (4 in exceptional cases; cross-EIP interactions is uncapped); nominal maximum 72.

Complexity profile

Each segment is one criterion's contribution to the Human total. Hover or focus a segment for its score and rationale.

Top complexity drivers

Added opcodes3
Edge/boundary conditions2
Performance risks1

Criterion breakdown

EIP-8024 Amsterdam / Glamsterdam: Human criterion scores and rationale
Criterion	Score	Why this score	Notes
Added opcodes	3	Introduces 3 new opcodes	—
Edge/boundary conditions	2	No rationale recorded.	—
Performance risks	1	Performance may be impacted if a client implementation doesn't keep the whole stack in memory	—

Show 21 zero-score criteria

Zero-score criteria (Checklist revision 1)
Criterion	Why this score	Notes
Modified opcodes	No rationale recorded.	—
Added precompiles	No rationale recorded.	—
Modified precompiles	No rationale recorded.	—
Added system contracts	No rationale recorded.	—
Modified system contracts	No rationale recorded.	—
EVM Gas rule changes	No rationale recorded.	—
Blob gas accounting changes	No rationale recorded.	—
New EVM gas refund	No rationale recorded.	—
New transaction types	No rationale recorded.	—
New or modified transaction validity mechanisms	No rationale recorded.	—
New block / header fields	No rationale recorded.	—
Encoding changes (RLP/SSZ)	No rationale recorded.	—
Block syncing changes	No rationale recorded.	—
New fork activation mechanism	No rationale recorded.	—
Engine API changes	No rationale recorded.	—
Engine API encoding changes	No rationale recorded.	—
Transition-tool interface changes	No rationale recorded.	—
Patterns affecting pre-existing tests	No rationale recorded.	—
Security risks	No rationale recorded.	—
Cryptography	No rationale recorded.	—
Cross-EIP interactions	No rationale recorded.	—

Assessment provenance

Assessed EIP revision: ethereum/EIPs@db5c483ea1 EIPS/eip-8024.md committed 2025-11-04
EIP master revision at the time of the human checklist commit; the checklist itself does not pin an EIP revision.
Current master · File history · blob 6d23fa7554 · sha256 eb387a1073ee
Rubric: Checklist revision 1 · ethspecs/pm@d936bcb349
Evaluator: STEEL team · ethspecs/pm complexity_assessments
Source record: Merged checklist ethspecs/pm@e4f314d97a complexity_assessments/EIPs/eip8024.md · committed 2025-11-05
blob 466f9a56d9 · sha256 b5a8ce9a9638
Research record: research/tasks/05c-amsterdam-human-assessment-alignment/inputs/human/eip-8024.yaml · sha256 4f3e36e04092

The LLM applied checklist revision 3 and the human reviewers revision 1 to EIP-8024 in Amsterdam / Glamsterdam. Revision 3 phrases the same criteria more precisely; differences cover the 23 criteria both revisions share, and each total keeps its own revision. Δ is LLM minus Human.

LLM11Low

Human6Low

Δ total+5Same tier

Criteria20/23agree exactly · 3 differ by 1 · 0 differ by 2+

Confounded comparison. The human checklist evaluated the EIP as it stood when the checklist was written; the LLM evaluated the sealed historical revision. Input alignment: substantive drift; human hindsight exposure: low exposure.

Exposure evidence

The client-performance comment is hypothetical and the assessment identifies no visible implementation, devnet, or completed test evidence.

Substantive intervening revisions: Shifts the EXCHANGE operand encoding down by one so the assembly operands match the intended SWAP-like indexing. decode_pair returns (q + 1, r + 1) / (r + 1, 29 - q) instead of (q + 2, r + 2) / (r + 2, 30 - q), and encode_pair's assertion and arithmetic change from '2 <= n <= 14 and n < m <= 30 and n + m <= 32' with the m <= 17 branch to '1 <= n <= 13 and n < m <= 29 and n + m <= 30' with the m <= 16 branch. A Rationale paragraph is added explaining that the operands look off by one because EXCHANGE n m operates on stack depths n + 1 and m + 1, chosen so tha…

Complexity profiles side by side

LLM

Human

Largest disagreements: Patterns affecting pre-existing tests (+1), Security risks (+1), Cross-EIP interactions (+1)

Show differences only (9 criteria)

Per-criterion scores, Human versus LLM, ordered by the size of the difference
Criterion	LLM	Human	Δ	Agreement	Rationale from each source
Patterns affecting pre-existing tests	1	0	+1	Differ by 1	Show rationale LLM Baseline tests that treat 0xe6–0xe8 as undefined and expect an exceptional halt must now expect execution when the immediate is valid. That rework is confined to a few cases in the undefined-opcode family, so this is level 1. Human No rationale recorded.
Security risks	1	0	+1	Differ by 1	Show rationale LLM The new security condition, preserving jump-target analysis and halting on invalid immediates, can be checked locally within the EVM interpreter and its jumpdest analysis. This is level 1. Human No rationale recorded.
Cross-EIP interactions	1	0	+1	Differ by 1	Show rationale LLM Only local compatibility checks with existing opcode and jump-analysis behavior are needed. The target's behavior can otherwise be tested on its own, so this is level 1. Human No rationale recorded.
Added opcodes	3	3	0	Agree	Show rationale LLM Multiple instructions are introduced, and all of them are complex because they carry immediate data. This is level 3. Human Introduces 3 new opcodes
Modified opcodes	0	0	0	Agree	Show rationale LLM Only previously undefined bytes gain meaning, which is counted under Added opcodes. No existing instruction's semantics or availability changes. Human No rationale recorded.
Added precompiles	0	0	0	Agree	Show rationale LLM None added. Human No rationale recorded.
Modified precompiles	0	0	0	Agree	Show rationale LLM None modified. Human No rationale recorded.
Added system contracts	0	0	0	Agree	Show rationale LLM None added. Human No rationale recorded.
Modified system contracts	0	0	0	Agree	Show rationale LLM None modified. Human No rationale recorded.
EVM Gas rule changes	0	0	0	Agree	Show rationale LLM The new instructions only have constant per-opcode costs. No accounting rule or baseline gas result changes, so this is level 0. Human No rationale recorded.
Blob gas accounting changes	0	0	0	Agree	Show rationale LLM No blob-gas accounting changes. Human No rationale recorded.
New EVM gas refund	0	0	0	Agree	Show rationale LLM No new refund mechanism. Human No rationale recorded.
New transaction types	0	0	0	Agree	Show rationale LLM None introduced. Human No rationale recorded.
New or modified transaction validity mechanisms	0	0	0	Agree	Show rationale LLM No transaction-validity or intrinsic-gas changes. Human No rationale recorded.
New block / header fields	0	0	0	Agree	Show rationale LLM None added. Human No rationale recorded.
Encoding changes (RLP/SSZ)	0	0	0	Agree	Show rationale LLM The immediate encoding is part of contract bytecode, not a protocol serialization schema. Human No rationale recorded.
Block syncing changes	0	0	0	Agree	Show rationale LLM No block RLP or structural validation changes. Human No rationale recorded.
New fork activation mechanism	0	0	0	Agree	Show rationale LLM No activation-specific state transition is required. Human No rationale recorded.
Engine API changes	0	0	0	Agree	Show rationale LLM No Engine API changes. Human No rationale recorded.
Transition-tool interface changes	0	0	0	Agree	Show rationale LLM The transition tool's interface does not change. Human No rationale recorded.
Performance risks	1	1	0	Agree	Show rationale LLM Component benchmarks of deep DUPN, SWAPN and EXCHANGE are enough to confirm that 3 gas is adequate, including immediate decoding at stack depths up to 235. No end-to-end performance assumptions change, so this is level 1. Human Performance may be impacted if a client implementation doesn't keep the whole stack in memory
Edge/boundary conditions	2	2	0	Agree	Show rationale LLM Several independent boundary-sensitive mechanisms are introduced: the invalid-immediate ranges for each opcode, the piecewise decode branches, stack-depth reachability (n relative to stack height, and DUPN at 1024 items), and the JUMPDEST/PUSH compatibility boundary. None forms an elevated matrix whose combinations cannot be tested separately, so this is level 2. Human No rationale recorded.
Cryptography	0	0	0	Agree	Show rationale LLM No cryptography is added or changed. Human No rationale recorded.
State-access ordering within opcode execution	0	n/a	—	Only in revision 3	Show rationale LLM No state is accessed and no instruction's access ordering changes. Human No rationale recorded.
State gas accounting changes	0	n/a	—	Only in revision 3	Show rationale LLM No state-gas accounting changes. Human No rationale recorded.
Engine API encoding changes	n/a	0	—	Only in revision 1	—
New invariant on pre-existing tests	0	n/a	—	Only in revision 3	Show rationale LLM Baseline tests need no new assertion. Human No rationale recorded.
New test-framework primitives	1	n/a	—	Only in revision 3	Show rationale LLM The framework's opcode and bytecode builder needs a local extension to encode the operand-to-immediate mapping, and to emit raw invalid immediates. No new abstraction is required, so this is level 1. Human No rationale recorded.
Unspecified behavior requiring cross-client consensus	1	n/a	—	Only in revision 3	Show rationale LLM Several localized details are omitted, but general EVM rules support one intended outcome for each: exceptional halt on underflow/overflow, and zero-padded code for a missing immediate. Because every failure path consumes all gas, the order of checks is not observable. This is level 1. Human No rationale recorded.

Compare EIP-8024 with other assessments All Amsterdam / Glamsterdam assessments

Criterion legend and glossary

Every stacked bar, comparison matrix, and criterion table on this site uses the same criterion colours, abbreviations, and order. Colour marks the criterion group; the abbreviation and name identify the criterion. Scores are 0–3 per criterion (4 is exceptional; cross-EIP interactions is uncapped).

EVM surface

Opcodes, precompiles, and system contracts that are added or modified.

OP+
Added opcodes
Introduces new opcodes
Score anchors
0
No new opcodes are introduced.
1
A new simple opcode is introduced (no data portion, no complex stack mechanics, and a constant gas cost).
2
Multiple new simple opcodes are introduced, or a single new complex opcode is introduced (has data portion, or complex stack mechanics, or a dynamic gas cost).
3
Multiple new opcodes are introduced, and at least one of them is complex (has data portion, or complex stack mechanics, or a dynamic gas cost).
- Cryptography opcodes are not considered complex by default. Refer to the "Cryptography" section for a separate assessment.
Modified opcodes
Modifies pre-existing opcodes
Score anchors
0
No pre-existing opcode modifications are introduced.
3
At least one pre-existing opcode's behavior is modified (not including gas changes) or a pre-existing opcode is deprecated.
PC+
Added precompiles
Introduces new precompiles
Score anchors
0
No new precompiles are introduced.
1
A new simple precompile is introduced (constant input length, constant gas cost).
2
Multiple new simple precompiles are introduced, or a single new complex precompile is introduced (dynamic input length or dynamic gas cost).
3
Multiple new precompiles are introduced, and at least one of them is complex (dynamic input length or dynamic gas cost).
- Cryptography precompiles are not considered complex by default. Refer to the "Cryptography" for a separate assessment.
Modified precompiles
Modifies pre-existing precompiles logic or gas-accounting
Score anchors
0
No pre-existing precompiles are modified.
1
At least one pre-existing precompile has its gas schedule modified.
2
Multiple pre-existing precompiles have their gas schedule modified, or a single pre-existing precompile has its behavior modified.
3
The behavior of multiple pre-existing precompiles, or a single complex pre-existing precompile modified.
Added system contracts
Introduces new system contract, stateful or not
Score anchors
0
No new system contracts are introduced.
1
A new system contract is introduced that is not stateful nor does it trigger a new system action (e.g. requests to the consensus layer).
2
Multiple new system contracts are introduced or a single new system contract that is either stateful or triggers a new system action (e.g. requests to the consensus layer).
3
Multiple new system contracts are introduced and at least one of them is either stateful or triggers a new system action (e.g. requests to the consensus layer).
Modified system contracts
Modifies pre-existing system contracts
Score anchors
0
No modifications to pre-existing system contracts are introduced, directly or indirectly.
1
Does not directly modify any system contract, but its behavior has minor indirect effects on one or more system contracts.
2
Does not directly modify any system contract, but its behavior has major indirect effects on one or more system contracts.
3
At least one pre-existing system contract code or state is modified, which would involve irregular state transition or a similarly complex transition methodology.

Gas and accounting

Execution, blob, and state gas rules, refunds, and where charges happen inside opcodes.

EVM Gas rule changes
New EVM gas accounting rules
Score anchors
0
No gas accounting changes.
1
Existing gas accounting mechanism is updated.
2
A new gas accounting mechanism is introduced but it does not affect existing mechanisms nor does it affect existing tests.
3
A new gas accounting mechanism is introduced and affects existing mechanisms which in turn affect existing tests.
ORD
State-access ordering within opcode execution · not in checklist revision 1
Changes *where inside an opcode's execution* state is accessed, or where gas is charged relative to that access. Because a state access is recorded in the block-level access list only if execution had enough gas to reach it, this ordering is consensus-critical: moving it changes the BAL at every gas boundary of every affected opcode.
Score anchors
0
No change to where state is accessed, or to where gas is charged relative to a state access, within any opcode.
1
A single opcode's state-access or gas-charge ordering changes.
2
Multiple opcodes' ordering changes, or a new state-accessing operation is introduced whose position in the order must be settled.
3
The ordering rule changes for a whole class of state-accessing opcodes at once, or what counts as a recordable state access is redefined — requiring existing BAL vectors to be re-derived across opcodes and forks.
- Distinct from "Modified opcodes", which asks whether an opcode's **result** changed. This row asks about the **path to the result**, which is observable even when the result is identical. An EIP can be 0 on that row and 3 on this one.
- Score changes **to** the ordering. Do not score the fact that state accesses are observable — they always are.
- Each boundary must be re-tested against every other dimension that can change the answer (cold/warm, static/non-static, delegated/direct, revert/success), so the case count grows multiplicatively rather than additively. Note this explicitly under Special Considerations.
Blob gas accounting changes
New Blob gas accounting rules which potentially affect pre-existing tests
Score anchors
0
No blob gas accounting changes.
1
Existing blob gas accounting mechanism is updated.
2
A new blob gas accounting mechanism is introduced but it does not affect existing mechanisms nor does it affect existing tests.
3
A new blob gas accounting mechanism is introduced and affects existing mechanisms which in turn affect existing tests.
SGAS
State gas accounting changes · not in checklist revision 1
New state gas accounting rules. State gas is the cost of *writing* state, as opposed to accessing or executing it: `StateGasCosts`, `COST_PER_STATE_BYTE`, the block-level state gas budget, and the spill path into execution gas.
Score anchors
0
No state gas accounting changes.
1
An existing state gas cost or `STATE_BYTES_PER_*` rate is adjusted.
2
A new state-gas-charging site is introduced, or the block-level state gas budget or reservoir allocation is modified.
3
A new state gas charging mechanism is introduced, or the spill interaction between state gas and execution gas is modified, affecting existing gas tests.
- Harder to test than blob gas: the spill path means state gas cannot be metered independently of execution gas, and some costs (e.g. `NEW_ACCOUNT`) are state-dependent.
New EVM gas refund
New gas-refund mechanism
Score anchors
0
No new gas-refund mechanisms are introduced.
1
A new simple gas-refund mechanism is introduced that does not affect either existing tests or existing gas-refund mechanisms.
2
A new complex gas-refund mechanism is introduced or a simple mechanism that affects existing tests or existing gas-refund mechanisms.
3
A new complex gas-refund mechanism is introduced that affects existing tests or existing gas-refund mechanisms.

Blocks, transactions, and encoding

Transaction types and validity, block and header fields, encodings, syncing, and activation-time changes.

New transaction types
Introduces a new transaction type
Score anchors
0
No new transaction types are introduced.
3
A new transaction type is introduced.
New or modified transaction validity mechanisms
Creates new or modifies pre-existing transaction types' validation mechanisms
Score anchors
0
No changes are introduced to the validity rules of existing transaction types or to their intrinsic gas cost calculation.
1
Minor adjustments are introduced to validity rules or intrinsic gas cost calculation, but they do not significantly affect existing tests.
2
Changes to validity rules or intrinsic gas cost calculation affect existing tests, but require only limited updates to test cases and no redesign of the testing infrastructure.
3
Changes to validity rules or intrinsic gas cost calculation require extensive rework or redesign of the tests or testing infrastructure.
New block / header fields
Introduces new block or block header fields
Score anchors
0
No new block or header fields are introduced.
3
A new block or header field is introduced.
ENC
Encoding changes (RLP/SSZ)
Introduces encoding changes at the transaction/block/interfaces level
Score anchors
0
No encoding changes are introduced at the transaction, block, or interfaces levels.
3
An encoding change is introduced at transaction, block or interfaces level (e.g. RLP -> SSZ).
- "Interfaces level" includes the Engine API. Score an Engine API encoding change (e.g. JSON -> SSZ) here.
Block syncing changes
Modifies block RLP validation mechanisms that require test client syncing.
Score anchors
0
No new RLP validation mechanism is introduced.
1
A single simple RLP validation mechanism is introduced.
2
Multiple simple RLP validation mechanisms are introduced or a single complex one.
3
Multiple RLP validation mechanisms are introduced and at least one of them is deemed complex.
ACT
New fork activation mechanism
Modifies state, internal variables, or similar, at the fork activation block
Score anchors
0
No state modifications, internal variables or similar are modified at the fork activation block.
3
Either a state modification or internal variables are modified at the fork activation block.
- Initialization of new internal variable is not considered a modification.

Client interfaces

Engine API and transition-tool interface changes.

Engine API changes
Introduces new fields to the Engine API directives
Score anchors
0
No new fields or communication mechanisms are introduced to the Engine API.
1
A single new field is introduced in one of the Engine API endpoints.
2
Multiple fields are introduced to one or multiple Engine API end points, or a new Engine API end-point is introduced.
3
Multiple fields are introduced to one or multiple Engine API end points and a new Engine API end-point is introduced.
Engine API encoding changes · Checklist revision 1 only
Engine API encoding changes (the revision-1 template defines no anchor text for this row).
T8N
Transition-tool interface changes
Modifies or adds new fields to the transition tool interface.
Score anchors
0
No modifications to the transition tool interface are required.
1
A single new field needs to be introduced to the transition tool interface.
2
Multiple new fields or a new mechanism has to be introduced to the transition tool interface.
3
Multiple new fields and a new mechanism has to be introduced to the transition tool interface.
- Special consideration must be paid to this section if the EIP introduces a mechanism that requires the state transition tool to be aware whether the block it is processing is the fork-activation block.

Testing impact

Rework, new invariants, and new primitives required in the test framework.

Patterns affecting pre-existing tests
Implements a new validation mechanism or rule that translates in reworking pre-existing tests
Score anchors
0
No pre-existing tests are affected by this change.
1
Minor subset of existing tests are affected by this change.
2
Considerable subset of existing tests are affected by this change but involves only a contrived category of tests.
3
Major subset of existing tests are affected, including diverse category of tests (benchmarks, static, multiple forks, etc.).
INV
New invariant on pre-existing tests · not in checklist revision 1
Tests that are **not about this EIP** must nonetheless assert something this EIP produces. Their logic does not change; they gain a new thing to check.
Score anchors
0
Pre-existing tests assert nothing new.
1
A narrow, contrived category of pre-existing tests gains a new assertion.
2
A broad category gains a new assertion, applied mechanically.
3
Every test in the fork gains the assertion regardless of what it tests, and pre-fork vectors must be re-derived to satisfy it.
- Paired with the row above, and easy to confuse with it. "Patterns affecting pre-existing tests" asks whether existing tests must be **reworked**; this row asks whether they must **additionally assert something new**. Score both — an EIP can be low on one and high on the other.
New test-framework primitives · not in checklist revision 1
Requires new abstractions in the test framework itself — expectation types, modifiers, helpers — beyond writing test functions with what already exists.
Score anchors
0
Existing test primitives suffice.
1
Existing primitives need minor extension.
2
New expectation or modifier primitives are required, reusable within this EIP's own test suite.
3
New framework-level primitives are required that become a permanent part of the framework and are used by other EIPs' tests.

Risk and validation

Security, performance, boundary conditions, and cryptography that need validation.

Security risks
Introduces or modifies mechanisms that could compromise the security of the chain, users, validators, or other stakeholders, if not implemented properly.
Score anchors
0
No new mechanisms are introduced that could pose a security risk.
1
The introduced mechanisms are self-contained, can be validated in isolation, and do not alter existing invariants that could pose a security risk for any stakeholders.
2
The introduced mechanisms interact with a limited number of existing components, slightly altering their security assumptions and requiring a targeted security review or fuzzing.
3
The introduced mechanisms interact with multiple existing components, including critical ones, substantially altering their security assumptions and requiring an extensive security review and fuzzing.
Performance risks
Introduces or modifies mechanisms and requires performance validation.
Score anchors
0
No new mechanisms are introduced that require performance validation.
1
The introduced mechanisms can be benchmarked in isolation and do not affect existing performance behavior.
2
The introduced mechanisms cannot be fully benchmarked in isolation, but they only have a limited impact on the existing performance benchmarks.
3
The introduced mechanisms cannot be benchmarked in isolation and have a substantial impact on existing performance benchmarks or have complex interactions with existing mechanisms.
Edge/boundary conditions
Feature contains edge/boundary conditions.
Score anchors
0
No discernible edge cases or boundary conditions are introduced.
1
A single edge-case or boundary-condition prone mechanism is introduced.
2
Multiple edge-case or boundary-condition prone mechanisms are introduced, but none of them requires an elevated number of cases to test.
3
Multiple edge-case or boundary-condition prone mechanisms are introduced and at least one of them requires an elevated number of cases to test.
Cryptography
Introduces new cryptography mechanisms or modifies existing functionality that involves cryptography
Score anchors
0
No cryptography mechanisms are introduced.
1
A new cryptography mechanism is introduced but it is a well known mechanism that is known to have vast resources to aid on its testing.
2
Multiple new cryptography mechanisms are introduced that are well-known or a single but novel mechanism is introduced that is either untested or has limited resources.
3
Multiple new cryptography mechanisms are introduced and at least one of them is a novel mechanism.

Coordination

Cross-EIP interactions and behavior that clients must agree on before tests exist.

XEIP
Cross-EIP interactions
Introduces or modifies mechanisms that affect other EIPs in either the same or past forks.
Score anchors
0
Fully self-contained EIP that does not depend on, modify, or conflict with any other EIP.
1
The EIP interacts with one or more other EIPs in a non-critical and limited way but can be tested independently for the most part.
2
The EIP depends on or modifies one or more other EIPs such that coordinated testing and consideration is required, but interactions are limited in scope and not complex.
3
The EIP has strong interdependencies with multiple EIPs, requiring extensive coordinated cross-EIP testing as well as potential re-design of existing test vectors.
- +1 for every 3 additional interacting EIPs beyond the first 3, each of which requires its own coordinated test cases. List the EIPs in the rationale.
- This row is intentionally uncapped, unlike every other anchor: each interacting EIP is another axis of the test matrix, so a ceiling would make a 12-EIP product indistinguishable from a 3-EIP one.
UNSP
Unspecified behavior requiring cross-client consensus · not in checklist revision 1
The EIP text does not determine the answer for cases a test can construct. Clients must agree on a previously unspecified detail before tests can be baselined. The cost here is coordination and re-baselining, not test writing.
Score anchors
0
The EIP text determines the answer for every case a test could construct.
1
A few details are unspecified but have an obvious intended reading.
2
Details require client agreement before tests can be written, but they are localized.
3
A previously unspecified *and previously unobservable* behavior becomes consensus-critical; expect tests to be re-baselined on each round of EIP amendment.
- Score this from the EIP's state at assessment time: whether it has client implementations, whether it has been through a devnet, and how many open questions remain on its discussion thread.