EIP complexity assessment

EIP-7843: SLOTNUM opcode

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 2025-06-09Included by cutoffLayers: execution

LLM Completescore 19

Human Completescore 7 · Checklist revision 1· merged checklist

LLM · Checklist revision 32026-10-08 · Opus 5.5 · primary · 19 Human · Checklist revision 1Complete · 7 CompareHuman vs LLM · shared criteria

Evaluated on: 2026-10-08 · Spec revision: 2025-05-20 · 0aefdc9d5a

Scope at the cutoff. EIP-7843 (revision 0aefdc9d) adds a SLOTNUM opcode at 0x4b. It takes no inputs, pushes the current block's slot number (described as an 8-byte big-endian uint) and costs a fixed 2 gas. The consensus layer computes the slot number and passes it to the execution layer through a new uint64 `slot_number` field in the Engine API `PayloadAttributes`. The execution header encoding also gets a uint64 `slot_number` field, so each block carries the value without extra inputs. The EIP does not specify the header field's position, how the field is validated, the newPayload/ExecutionPayload changes, Engine method versioning, or the genesis value.

19MediumMedium

Evaluator: LLMChecklist v3
Confidence: Medium
Under-specified at assessment cutoff: Yes — 4 criteria affected
Plausible range: 18–23 (Medium–High)
Assessment cutoff: 2025-06-09 · EIP revision 0aefdc9d5a (2025-05-20)

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.

Top complexity drivers

New block / header fields3
Encoding changes (RLP/SSZ)3
New invariant on pre-existing tests2
Unspecified behavior requiring cross-client consensus2

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: The EIP adds a header field and a PayloadAttributes field but does not say where the field goes in the header RLP. It also gives no validation rule for imported blocks, no ExecutionPayload/newPayload or method-versioning changes, and no genesis or fork-transition value.

Plausible total

18–23
recorded score 19 · plausible tiers Medium, High

Unresolved questions at the cutoff (4)

Where does slot_number go in the header RLP list?
How does newPayload/ExecutionPayload carry slot_number, and must the EL validate it against the CL value, the timestamp or the parent slot?
Are new versioned Engine API methods required?
What slot_number value applies at genesis or the fork block?

Notable ambiguities noted by the assessor (3)

The value is called an '8 byte uint in big endian encoding', but the EVM stack is 256-bit; zero-extension is presumably intended but not stated.
There is no stated consistency rule between slot_number and the block timestamp.
Engine API changes are described only for PayloadAttributes, not for ExecutionPayload.

Criterion breakdown

EIP-7843 Amsterdam / Glamsterdam: LLM criterion scores and rationale
Criterion	Score	Why this score	Evidence / uncertainty
New block / header fields	3	The execution header schema gains a slot_number member that clients must produce and read.	eip.md · Header extension - "`slot_number` field of type `uint64`" A new member is added to the execution block header. Confidence: High
Encoding changes (RLP/SSZ)	3	The block header RLP schema and the Engine API PayloadAttributes schema both gain a serialized field.	eip.md · Header extension - "The header encoding shall be extended to include a `slot_number` field" The execution header RLP schema gains a uint64 field. eip.md · PayloadAttributes change The Engine API PayloadAttributes JSON schema gains a field. Confidence: High Uncertainty: The field's position in the header RLP list is not specified.
New invariant on pre-existing tests	2	Every post-fork block test must include and check the new header field. That is a universal assertion within the fork. Pre-fork vectors are not affected, so the rubric caps this at level 2.	eip.md · Header extension - "include a `slot_number` field of type `uint64`" Every post-fork block header carries a new field that block tests must produce and check. Confidence: Medium
Unspecified behavior requiring cross-client consensus	2	Localized but competing outcomes affect block hashes and validity: where the field sits in the header, how imported blocks validate it, and what the genesis or fork-block value is. Clients must agree on these before fixtures can be fixed.	eip.md · Header extension The field's position in the header RLP list is not given; this affects block hashes. eip.md · PayloadAttributes change Only PayloadAttributes is changed; it is not stated how newPayload/ExecutionPayload carries or validates slot_number. eip.md · Specification There is no validation rule (e.g. consistency with timestamp or parent) and no genesis value. Confidence: Medium Uncertainty: A later revision or Engine API spec may define these; neither was supplied.
Added opcodes	1	Exactly one simple instruction is introduced.	eip.md · Specification - "A new opcode `SLOTNUM` is introduced at `0x4b`. It shall return one stack element." One opcode with no immediates, fixed stack effects (0 in, 1 out) and constant gas of 2. Confidence: High
Block syncing changesUnder-specified	1	Block import must decode and structurally check the one new field (presence and uint64 size) after the fork: a single simple rule. No consistency check against other fields or blocks is specified.	eip.md · Header extension Header RLP decoding must accept the new uint64 field post-fork. eip.md · Rationale / ZK-VM proving - "The slot number is included in the block header" The block carries the slot number itself; no validation rule is stated. Confidence: Low Uncertainty: The validation rule for slot_number is unspecified. A check against the timestamp, the parent's slot or the CL-supplied value would be a complex rule (level 2).
Engine API changesUnder-specified	1	Exactly one semantic field (slot_number) is specified. No new method version or endpoint behavior is stated.	eip.md · PayloadAttributes change - "extended to include a `slot_number` field of type `uint64`" One semantic field is added to PayloadAttributes. Confidence: Low Uncertainty: Building the header from ExecutionPayload in newPayload implies the payload must also carry the field (the same semantic field). Changing PayloadAttributes plausibly requires new versioned methods, which would make this level 2–3. None of this is specified.
Transition-tool interface changes	1	One semantic field (the slot number in the block environment and header) is added. The tool's operation is otherwise unchanged.	eip.md · RPC changes - "The slot number is calculated in the consensus layer and passed to the execution layer" The slot number is an external block-environment input that the state-transition tool must receive (and echo in the header). Confidence: Medium Uncertainty: No tool evidence was supplied; the field name and placement are assumptions.
Patterns affecting pre-existing tests	1	The only behavioral rework is the 0x4b boundary case in the undefined/invalid-opcode family: it must now succeed instead of halting. That is a parameter case within one family. The header-field plumbing is assessed under INV/HDR/ENC.	eip.md · Abstract - "new opcode `SLOTNUM` (`0x4b`)" 0x4b was previously undefined, so baseline invalid-opcode cases that use it now behave differently. eip.md · Header extension The header gains a field. Baseline block construction must supply it, but that is fixture plumbing rather than a change to a behavioral rule. Confidence: Medium Uncertainty: If changed block hashes from the extra header field count as rework of expected results across all blockchain fixtures, this could be scored higher.
New test-framework primitives	1	Existing header/environment and opcode primitives need local extensions; no new abstraction is required.	eip.md · Header extension The framework's header and environment models need a new field. eip.md · Specification - "A new opcode `SLOTNUM` is introduced at `0x4b`" The opcode must be added to the framework's opcode definitions. Confidence: Medium
Security risksUnder-specified	1	Contracts can now read a CL-provided header value. Its correctness (header value matching the CL value, uint64 bounds) can be checked locally without changing other components' assumptions.	eip.md · Calculation in consensus layer The EL trusts the slot number computed by the CL. eip.md · Security Considerations - "None." The EIP states no security considerations. Confidence: Low Uncertainty: The validation rule is unspecified, so the exact security boundary is unclear.
Edge/boundary conditionsUnder-specified	1	One boundary-sensitive mechanism: the uint64 slot-number range, covering header decoding of oversized values and stack representation at 0 and 2^64-1.	eip.md · Header extension - "field of type `uint64`" The slot number is bounded to uint64, both in the header and in the value the opcode returns. eip.md · Stack - "`SlotNumber` is an 8 byte uint in big endian encoding" The 8-byte value must be represented correctly on the 256-bit stack (zero, max uint64). Confidence: Low Uncertainty: A validation rule tying slot_number to the timestamp or parent block is not specified. If one were added, it would add a second boundary-sensitive rule.
Cross-EIP interactions	1	The new header field extends a header schema that includes EIP-4788's parent_beacon_block_root, so header encoding and ordering need a local compatibility check. The SLOTNUM value could also be cross-checked against beacon-root proofs. Otherwise the opcode can be tested on its own.	eip.md · Motivation - "prove it against the beacon block root (using EIP-4788)" EIP-4788 is cited as an alternative way to obtain the slot number. supporting/eip-4788.md · Block structure and validity - resulting RLP encoding EIP-4788 defines parent_beacon_block_root in the header schema that slot_number extends. Confidence: Low Uncertainty: The EIP-4788 citation is mostly motivational, so the interaction could arguably be scored 0. Interacting EIPs: EIP-4788

Show 15 zero-score criteria

Zero-score criteria (Checklist revision 3)
Criterion	Why this score	Evidence / uncertainty
Modified opcodes	No existing instruction's semantics change.	eip.md · Specification No existing opcode changes.
Added precompiles	None.	eip.md · Specification No precompile is introduced.
Modified precompiles	None.	eip.md · Specification No precompile changes.
Added system contracts	None.	eip.md · Specification No system contract is introduced.
Modified system contracts	No system contract's rules or surrounding behavior change.	eip.md · Motivation - "prove it against the beacon block root (using EIP-4788)" EIP-4788 is mentioned only as an alternative approach; its contract is unchanged.
EVM Gas rule changes	Giving a new opcode a constant base-tier cost is not a new gas-accounting mechanism and does not change any existing accounting rule. Its gas cost is tested under the opcode criterion.	eip.md · Gas Cost - "fixed fee of `2`" The new opcode has a constant cost of 2 gas. eip.md · Rationale / Gas Price - "priced to match similar opcodes in the `W_base` set" The cost reuses the existing W_base tier; no accounting rule changes.
State-access ordering within opcode execution	No state access or gas-charge ordering is introduced or changed.	eip.md · Specification - "It shall return one stack element." SLOTNUM reads a block-context value only; it does not access state.
Blob gas accounting changes	No blob-gas rules change.	eip.md · Specification Blob gas is not mentioned.
State gas accounting changes	No state-gas accounting changes.	eip.md · Specification No state-writing cost changes.
New EVM gas refund	No refund mechanism is introduced.	eip.md · Gas Cost Only a fixed cost is defined; no refund is introduced.
New transaction types	None.	eip.md · Specification No transaction type is introduced.
New or modified transaction validity mechanisms	None.	eip.md · Specification No transaction validity or intrinsic-gas rule changes.
New fork activation mechanism	Activation only selects new rules: the opcode becomes valid and the header field is required. No one-time state transition is needed.	eip.md · Specification No state migration or code installation is required at activation.
Performance risks	No new or changed workload needs performance validation.	eip.md · Rationale / ZK-VM proving - "similar to existing opcodes such as `TIMESTAMP`" The workload is a trivial constant-cost read of block context.
Cryptography	No cryptographic rule changes.	eip.md · Specification No cryptographic operation is introduced.

Assessment provenance

Assessed EIP revision: ethereum/EIPs@0aefdc9d5a EIPS/eip-7843.md committed 2025-05-20 · information cutoff 2025-06-09T07:29:29Z
Current master · File history · blob 0f5d0ef12b · sha256 9f15ade995d4
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-7843.yaml · sha256 1361e740cecf
Supporting documents supplied with the EIP: supporting/eip-4788.md

Evaluated on: Not recorded · Spec revision: 2025-06-09 · 77f096af0c

7LowLow

Evaluator: HumanChecklist v1
Confidence: Not recorded
Under-specified at assessment cutoff: Not recorded in the checklist
Checklist published: 2025-11-07 · EIP at 77f096af0c
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

New block / header fields3
Added opcodes1
Engine API changes1
Transition-tool interface changes1

Criterion breakdown

EIP-7843 Amsterdam / Glamsterdam: Human criterion scores and rationale
Criterion	Score	Why this score	Notes
New block / header fields	3	No rationale recorded.	—
Added opcodes	1	New opcode added: `SLOTNUM`	—
Engine API changes	1	new field, `slot_number` is passed in the engine API	—
Transition-tool interface changes	1	new field, `slot_number` will need to be added	—
Edge/boundary conditions	1	Minimal, but need to check 0, and `uint64` big endian	—

Show 19 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.	—
Encoding changes (RLP/SSZ)	No rationale recorded.	—
Block syncing changes	No rationale recorded.	—
New fork activation mechanism	No rationale recorded.	—
Engine API encoding changes	No rationale recorded.	—
Patterns affecting pre-existing tests	No rationale recorded.	—
Security risks	No rationale recorded.	—
Performance risks	No rationale recorded.	—
Cryptography	No rationale recorded.	—
Cross-EIP interactions	No rationale recorded.	—

Assessment provenance

Assessed EIP revision: ethereum/EIPs@77f096af0c EIPS/eip-7843.md committed 2025-06-09
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 aeeffed14e · sha256 56d948e7e04e
Rubric: Checklist revision 1 · ethspecs/pm@d936bcb349
Evaluator: STEEL team · ethspecs/pm complexity_assessments
Source record: Merged checklist ethspecs/pm@6b2c7cd0b1 complexity_assessments/EIPs/EIP-7843.md · committed 2025-11-07
blob 1bb42233b4 · sha256 5f036b6626bc
Research record: research/tasks/05c-amsterdam-human-assessment-alignment/inputs/human/eip-7843.yaml · sha256 70779e4b9d45

The LLM applied checklist revision 3 and the human reviewers revision 1 to EIP-7843 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.

LLM19Medium

Human7Low

Δ total+12Tiers differ: Medium vs Low

Criteria18/23agree exactly · 4 differ by 1 · 1 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: no substantive drift; human hindsight exposure: low exposure.

Exposure evidence

The assessment describes required future interface fields and does not identify implementation or test outcomes.

Every intervening EIP revision is classified non-substantive by Task 01.

Complexity profiles side by side

LLM

Human

Largest disagreements: Encoding changes (RLP/SSZ) (+3), Patterns affecting pre-existing tests (+1), Block syncing changes (+1), Security risks (+1), Cross-EIP interactions (+1)

Show differences only (11 criteria)

Per-criterion scores, Human versus LLM, ordered by the size of the difference
Criterion	LLM	Human	Δ	Agreement	Rationale from each source
Encoding changes (RLP/SSZ)	3	0	+3	Differ by 2+	Show rationale LLM The block header RLP schema and the Engine API PayloadAttributes schema both gain a serialized field. Human No rationale recorded.
Block syncing changes	1	0	+1	Differ by 1	Show rationale LLM Block import must decode and structurally check the one new field (presence and uint64 size) after the fork: a single simple rule. No consistency check against other fields or blocks is specified. Human No rationale recorded.
Patterns affecting pre-existing tests	1	0	+1	Differ by 1	Show rationale LLM The only behavioral rework is the 0x4b boundary case in the undefined/invalid-opcode family: it must now succeed instead of halting. That is a parameter case within one family. The header-field plumbing is assessed under INV/HDR/ENC. Human No rationale recorded.
Security risks	1	0	+1	Differ by 1	Show rationale LLM Contracts can now read a CL-provided header value. Its correctness (header value matching the CL value, uint64 bounds) can be checked locally without changing other components' assumptions. Human No rationale recorded.
Cross-EIP interactions	1	0	+1	Differ by 1	Show rationale LLM The new header field extends a header schema that includes EIP-4788's parent_beacon_block_root, so header encoding and ordering need a local compatibility check. The SLOTNUM value could also be cross-checked against beacon-root proofs. Otherwise the opcode can be tested on its own. Human No rationale recorded.
Added opcodes	1	1	0	Agree	Show rationale LLM Exactly one simple instruction is introduced. Human New opcode added: `SLOTNUM`
Modified opcodes	0	0	0	Agree	Show rationale LLM No existing instruction's semantics change. Human No rationale recorded.
Added precompiles	0	0	0	Agree	Show rationale LLM None. Human No rationale recorded.
Modified precompiles	0	0	0	Agree	Show rationale LLM None. Human No rationale recorded.
Added system contracts	0	0	0	Agree	Show rationale LLM None. Human No rationale recorded.
Modified system contracts	0	0	0	Agree	Show rationale LLM No system contract's rules or surrounding behavior change. Human No rationale recorded.
EVM Gas rule changes	0	0	0	Agree	Show rationale LLM Giving a new opcode a constant base-tier cost is not a new gas-accounting mechanism and does not change any existing accounting rule. Its gas cost is tested under the opcode criterion. Human No rationale recorded.
Blob gas accounting changes	0	0	0	Agree	Show rationale LLM No blob-gas rules change. Human No rationale recorded.
New EVM gas refund	0	0	0	Agree	Show rationale LLM No refund mechanism is introduced. Human No rationale recorded.
New transaction types	0	0	0	Agree	Show rationale LLM None. Human No rationale recorded.
New or modified transaction validity mechanisms	0	0	0	Agree	Show rationale LLM None. Human No rationale recorded.
New block / header fields	3	3	0	Agree	Show rationale LLM The execution header schema gains a slot_number member that clients must produce and read. Human No rationale recorded.
New fork activation mechanism	0	0	0	Agree	Show rationale LLM Activation only selects new rules: the opcode becomes valid and the header field is required. No one-time state transition is needed. Human No rationale recorded.
Engine API changes	1	1	0	Agree	Show rationale LLM Exactly one semantic field (slot_number) is specified. No new method version or endpoint behavior is stated. Human new field, `slot_number` is passed in the engine API
Transition-tool interface changes	1	1	0	Agree	Show rationale LLM One semantic field (the slot number in the block environment and header) is added. The tool's operation is otherwise unchanged. Human new field, `slot_number` will need to be added
Performance risks	0	0	0	Agree	Show rationale LLM No new or changed workload needs performance validation. Human No rationale recorded.
Edge/boundary conditions	1	1	0	Agree	Show rationale LLM One boundary-sensitive mechanism: the uint64 slot-number range, covering header decoding of oversized values and stack representation at 0 and 2^64-1. Human Minimal, but need to check 0, and `uint64` big endian
Cryptography	0	0	0	Agree	Show rationale LLM No cryptographic rule changes. Human No rationale recorded.
State-access ordering within opcode execution	0	n/a	—	Only in revision 3	Show rationale LLM No state access or gas-charge ordering is introduced or changed. 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	2	n/a	—	Only in revision 3	Show rationale LLM Every post-fork block test must include and check the new header field. That is a universal assertion within the fork. Pre-fork vectors are not affected, so the rubric caps this at level 2. Human No rationale recorded.
New test-framework primitives	1	n/a	—	Only in revision 3	Show rationale LLM Existing header/environment and opcode primitives need local extensions; no new abstraction is required. Human No rationale recorded.
Unspecified behavior requiring cross-client consensus	2	n/a	—	Only in revision 3	Show rationale LLM Localized but competing outcomes affect block hashes and validity: where the field sits in the header, how imported blocks validate it, and what the genesis or fork-block value is. Clients must agree on these before fixtures can be fixed. Human No rationale recorded.

Compare EIP-7843 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.