EIP complexity assessment

EIP-2488: Deprecate the CALLCODE opcode

Assessed in Hegotá. The score describes the EIP text available at the snapshot, not the EIP as it stands today.

ProspectiveHegotáSnapshot 2026-08-25PFI at snapshotLayers: execution

LLM Completescore 10

Human Available in open PRscore 13 · Checklist revision 2· ethspecs/pm #114

LLM · Checklist revision 22026-08-26 · Original snapshot · 10 Human · Checklist revision 2Available in open PR · 13 CompareHuman vs LLM · same checklist revision

Evaluated on: 2026-08-26 · Spec revision: 2026-08-25 · ac450a4ab2 · Inclusion status at snapshot: PFI

Scope at the cutoff. Execution-layer assessment of the proposal to change CALLCODE (0xf2) at FORK_BLOCK so that it always returns 0. The sealed package describes a localized but breaking opcode deprecation, declares EIP-7 as a dependency, and leaves detailed opcode effects, tests, implementation, and security considerations unresolved.

10LowLow

Evaluator: LLMChecklist v2
Confidence: Medium
Under-specified at assessment cutoff: Yes — 3 criteria affected
Plausible range: 10–12 (Low–Medium)
Snapshot: 2026-08-25 · EIP revision ac450a4ab2 (2026-08-25)

Score bands · Checklist revision 2

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

Modified opcodes3
Security risks2
Unspecified behavior requiring cross-client consensus2
Patterns affecting pre-existing tests1

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 specification says only that post-fork CALLCODE always returns 0. It does not determine whether existing gas processing or state access occurs before that result, which other existing instruction effects remain, or a concrete FORK_BLOCK value. Test cases, implementation, and security considerations are also TBA.

Plausible total

10–12
recorded score 10 · plausible tiers Low, Medium

Affected criteria (3)

EVM Gas rule changes (0)
State-access ordering within opcode execution (0)
Unspecified behavior requiring cross-client consensus (2)

Unresolved questions at the cutoff (4)

Does CALLCODE retain its existing gas accounting before returning the forced failure value?
Does CALLCODE perform any state access after activation, and where is gas charged relative to it?
Which existing CALLCODE effects other than its returned result remain in force?
What concrete activation block replaces FORK_BLOCK?

Notable ambiguities noted by the assessor (2)

"Always returns 0" does not say whether the instruction follows any of its existing execution path before producing that result.
The backwards-compatibility claim about valuable contracts is explicitly unvalidated, and security considerations are absent.

Criterion breakdown

EIP-2488 Hegotá: LLM criterion scores and rationale
Criterion	Score	Why this score	Evidence / uncertainty
Modified opcodes	3	A pre-existing opcode is deprecated and its non-gas behavior is modified, which exactly matches the score-3 anchor. Exceptional score: Not applicable; score 3 is within the defined anchors.	eip.md · ## Abstract CALLCODE is explicitly deprecated by making it always return failure. eip.md · ## Specification After activation, CALLCODE (0xf2) always returns 0. Confidence: High Uncertainty: Detailed secondary effects are underspecified, but the deprecation and result change are explicit.
Security risks	2	The modified opcode has a limited interaction surface but changes assumptions for contracts that execute it, with acknowledged potential breakage and no completed security analysis. That warrants targeted review rather than the self-contained score-1 treatment. Exceptional score: Not applicable; score 2 is within the defined anchors.	eip.md · ## Backwards Compatibility The proposal is explicitly breaking and may break contracts; the expectation that no valuable contracts are affected remains a TODO to validate. eip.md · ## Security Considerations Security considerations are TBA. eip.md · ## Rationale Returning failure is chosen so a contract can detect the result and potentially recover. Confidence: Medium Uncertainty: The package neither validates affected-contract prevalence nor supplies security considerations, so the practical reach of the risk is unknown.
Unspecified behavior requiring cross-client consensusUnder-specified	2	Constructible CALLCODE cases cannot be baselined from the text until clients agree on the localized operational details surrounding the forced result. The uncertainty concerns one opcode, so score 2 fits better than the broad or newly observable score-3 condition. Exceptional score: Not applicable; score 2 is within the defined anchors.	eip.md · ## Specification The specification fixes only the returned failure value and does not define gas charging, state-access behavior, or which other existing CALLCODE effects remain. eip.md · ## Test Cases Test cases are TBA. eip.md · ## Implementation Implementation is TBA. Confidence: High Uncertainty: The assessment has no permitted evidence about implementations, devnets, or discussion state; the score rests only on omissions visible in the snapshot.
Patterns affecting pre-existing tests	1	Existing tests that exercise CALLCODE across the fork must be updated, but the affected set is the narrow subset centered on one opcode, matching the minor-subset anchor. Exceptional score: Not applicable; score 1 is within the defined anchors.	eip.md · ## Specification Post-fork CALLCODE executions must return failure rather than their prior result. eip.md · ## Backwards Compatibility The proposal explicitly identifies the change as breaking and potentially contract-breaking. Confidence: Medium Uncertainty: Test cases are TBA, so the package does not enumerate the actual regression set or demonstrate broader effects.
Edge/boundary conditions	1	The proposal introduces one explicit activation boundary at which the same opcode changes from its prior behavior to forced failure. Exceptional score: Not applicable; score 1 is within the defined anchors.	eip.md · ## Specification The new behavior applies exactly when block.number is greater than or equal to FORK_BLOCK. Confidence: High Uncertainty: FORK_BLOCK has no concrete value in the EIP, but the before/at-boundary test dimension is clear.
Cross-EIP interactions	1	There is one explicit, limited interaction with EIP-7. The proposal relies on DELEGATECALL as the historical replacement context but does not modify its specified behavior, so the interaction remains independently testable for the most part. Exceptional score: Not applicable; score 1 is within the defined anchors.	eip.md · Front matter: requires EIP-2488 declares EIP-7 as its sole required EIP. eip.md · ## Motivation The motivation says DELEGATECALL from EIP-7 rectified CALLCODE's intended design goal. supporting/eip-7.md · ### Overview EIP-7 defines DELEGATECALL as similar in idea to CALLCODE while changing sender and value propagation. Confidence: High Uncertainty: No other EIP interaction is identified by the package. Interacting EIPs: EIP-7

Show 22 zero-score criteria

Zero-score criteria (Checklist revision 2)
Criterion	Why this score	Evidence / uncertainty
Added opcodes	No new opcode is introduced.	eip.md · ## Abstract The proposal deprecates the existing CALLCODE opcode rather than allocating a new opcode. Uncertainty: The only opcode number named, 0xf2, is identified as CALLCODE's existing instruction.
Added precompiles	No precompile is added.	eip.md · ## Specification The specification changes an opcode and introduces no precompile. Uncertainty: Precompiles are outside the stated scope.
Modified precompiles	No pre-existing precompile behavior or gas accounting is modified.	eip.md · ## Specification No precompile logic or precompile gas schedule is mentioned. Uncertainty: The proposal identifies only CALLCODE.
Added system contracts	No system contract is added.	eip.md · ## Specification The proposal changes CALLCODE behavior and does not introduce contract code or state. Uncertainty: The package identifies no system-contract deployment or system action.
Modified system contracts	No direct or package-grounded indirect modification of a system contract is specified.	eip.md · ## Specification The proposal names only CALLCODE and identifies no pre-existing system contract. Uncertainty: The EIP warns generically about affected contracts but does not identify any as system contracts, so no such interaction can be inferred.
EVM Gas rule changesUnder-specified	No gas-accounting change is specified, so the zero anchor applies. Whether existing CALLCODE charging remains in force is a material specification gap recorded separately.	eip.md · ## Specification The only stated post-fork rule is that CALLCODE always returns 0; the specification states no gas-accounting rule. Uncertainty: The text does not say whether existing gas processing occurs before the forced failure, so a later clarification could change this row.
State-access ordering within opcode executionUnder-specified	The proposal does not specify a change to state-access or gas-charge ordering within CALLCODE, so the zero anchor applies on the sealed text.	eip.md · ## Specification The forced return value is specified without defining any state access or the position of gas charging relative to an access. Uncertainty: It is unresolved whether the deprecated instruction retains or bypasses any pre-existing access path; that localized ambiguity could make this a single-opcode ordering change.
Blob gas accounting changes	No blob-gas accounting mechanism is introduced or updated.	eip.md · ## Specification The specification only changes the result of CALLCODE and mentions no blob gas. Uncertainty: No blob-gas behavior is within the proposal's stated scope.
State gas accounting changes	No state-gas cost, charging site, budget, reservoir, or spill rule is changed.	eip.md · ## Specification The specification introduces no state write or state-gas charging rule. Uncertainty: The separate ambiguity about CALLCODE execution gas does not establish any change to state gas for writes.
New EVM gas refund	No new EVM gas refund is specified.	eip.md · ## Specification The post-fork forced-failure rule introduces no refund mechanism. Uncertainty: The EIP contains no refund proposal or refund parameters.
New transaction types	No transaction type is introduced.	eip.md · ## Specification The proposal changes CALLCODE execution and defines no transaction envelope. Uncertainty: The EIP contains no transaction-type specification.
New or modified transaction validity mechanisms	Existing transaction validity and intrinsic gas calculation are not modified.	eip.md · ## Specification The change applies during opcode execution and states no transaction validity or intrinsic-gas rule. Uncertainty: The execution result may change, but no transaction is declared invalid by this proposal.
New block / header fields	No new block or block-header field is introduced.	eip.md · ## Specification The existing block.number is used as an activation condition; no block or header field is added. Uncertainty: FORK_BLOCK is a threshold placeholder, not a proposed header field.
Encoding changes (RLP/SSZ)	No RLP, SSZ, or other transaction/block/interface encoding change is introduced.	eip.md · ## Specification The opcode-result rule adds no transaction, block, or interface encoding. Uncertainty: Encoding is outside the proposal's stated scope.
Block syncing changes	No block encoding or RLP validation mechanism requiring sync testing is introduced.	eip.md · ## Specification The specification changes an opcode result and introduces no block RLP validation rule. Uncertainty: The motivation mentions syncing clients, but proposes no change to block validation encoding.
New fork activation mechanism	The fork changes opcode semantics without modifying state or an internal variable at the activation block, so it does not meet the nonzero anchor.	eip.md · ## Specification Activation gates CALLCODE behavior on block.number but specifies no state or internal-variable modification at activation. Uncertainty: No activation-time initialization or irregular transition is described.
Engine API changes	No Engine API field, endpoint, or communication mechanism is introduced.	eip.md · ## Specification The only specified change is internal EVM opcode behavior, with no API fields or endpoints. Uncertainty: No Engine API surface appears in the proposal.
Transition-tool interface changes	No transition-tool interface field or mechanism is specified.	eip.md · ## Specification Activation is expressed through block.number and no transition-tool field is introduced. Uncertainty: FORK_BLOCK is not assigned a value, but that does not itself specify a new tool field.
New invariant on pre-existing tests	Tests unrelated to this EIP gain no additional invariant or mechanically applied assertion.	eip.md · ## Specification The rule changes CALLCODE behavior but defines no new output that unrelated tests must assert. Uncertainty: Test cases are TBA, but no package evidence identifies a cross-suite assertion.
New test-framework primitives	The specified result and fork boundary can be exercised with ordinary opcode-result tests; no new expectation, modifier, or helper is required by the package.	eip.md · ## Specification The observable requirement is a post-fork zero failure result for one existing opcode. eip.md · ## Test Cases The test-cases section is TBA and requests no framework abstraction. Uncertainty: The absent test plan prevents confirmation, but it supplies no basis for a nonzero score.
Performance risks	No new mechanism requiring performance validation is introduced; the specified path is a localized forced result.	eip.md · ## Motivation The stated benefit is reducing implementation burden for certain clients, not adding a performance-sensitive mechanism. eip.md · ## Specification The new behavior is a fixed failure result for one opcode. Uncertainty: Implementation is TBA, but the package identifies no performance risk or benchmark requirement.
Cryptography	No cryptographic mechanism or cryptographic functionality is added or modified.	eip.md · ## Abstract The proposal deprecates CALLCODE by making it return failure and introduces no cryptography. Uncertainty: Cryptography is outside the stated change.

Assessment provenance

Assessed EIP revision: ethereum/EIPs@ac450a4ab2 EIPS/eip-2488.md committed 2026-08-25 · information cutoff 2026-08-25T11:56:58Z
Current master · File history · blob 5af41eb8bf · sha256 e606d541a486
Rubric: Checklist revision 2 · ethspecs/pm@3d8c0128c5
Evaluator: gpt-5.6-sol at xhigh reasoning effort · isolation bubblewrap_one_eip_capsule_v1
Source record: Frozen research record research/tasks/08-hegota-prospective-complexity-assessment/outputs/assessments/hegota-pfi-2026-08-26/eip-2488.yaml · sha256 e3a1ee5c5b7f
Supporting documents in the sealed package: supporting/eip-7.md

Evaluated on: Not recorded

13MediumMedium

Evaluator: HumanChecklist v2
Confidence: Not recorded
Under-specified at assessment cutoff: Not recorded in the checklist
Checklist published: 2026-08-18
Source: open ethspecs/pm pull request #114

Score bands · Checklist revision 2

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 Human total. Hover or focus a segment for its score and rationale.

Top complexity drivers

Modified opcodes3
Patterns affecting pre-existing tests3
Unspecified behavior requiring cross-client consensus2
EVM Gas rule changes1

Criterion breakdown

EIP-2488 Hegotá: Human criterion scores and rationale
Criterion	Score	Why this score	Notes
Modified opcodes	3	CALLCODE (0xf2) is deprecated: its behaviour is replaced with an unconditional failure return.	—
Patterns affecting pre-existing tests	3	Major subset across diverse categories. CALLCODE appears in 63 hand-written test files and 353 files under `tests/ported_static/` in `execution-specs`. The ported static corpus is exactly the "static, multiple forks" case level 3 names: those tests were ported to run across every fork, so each one needs a fork-gated expectation once CALLCODE stops working.	—
Unspecified behavior requiring cross-client consensus	2	Left undetermined by the specification: whether gas is charged for the no-op call, whether the target is warmed under EIP-2929, whether value is transferred, whether the target appears in the block-level access list, whether memory arguments are still expanded, and whether the 1024 call-frame depth limit is still checked or a depth level still consumed. Clients must agree on all of these before tests can be baselined. Localized to one opcode, so 2 rather than 3.	—
EVM Gas rule changes	1	Existing gas accounting mechanism is updated. CALLCODE today carries the full CALL-family dynamic cost: base, cold/warm account access under EIP-2929, the value-transfer and new-account surcharges, memory expansion for the argument and return regions, and the 63/64 stipend reservation. The assumed behaviour is that the target is never warmed and no gas is consumed at all — the opcode pops its arguments, pushes 0, and charges nothing. That is the reading to specify, and it needs stating exactly, because the EIP's one-line specification says only that the instruction "always returns 0".	—
State-access ordering within opcode execution	1	A single opcode's state access changes — it disappears. Under the assumed behaviour above, CALLCODE stops touching the target account entirely, so the target is no longer warmed for subsequent opcodes under EIP-2929 and no longer contributes an entry to the block-level access list. Both are observable, so the removal has to be tested rather than assumed.	—
Security risks	1	Self-contained and validatable in isolation. Contracts that still call CALLCODE will break, but the failure is a returned 0 rather than an exceptional halt, so callers retain the chance to handle it. No existing invariant outside the opcode itself is altered.	—
Edge/boundary conditions	1	One boundary-prone mechanism: the always-fail path. Cases are that the opcode still pops the correct number of stack items and pushes 0, that memory arguments are not expanded, that the target stays cold, and that gas is unchanged across the call. Small, fixed set.	—
Cross-EIP interactions	1	Interacts with one other EIP in a limited way, and can be tested independently for the most part: EIP-7928 (block-level access lists) — whether a failed CALLCODE still contributes the target to the BAL is consensus-observable and needs settling, but CALLCODE's own cases can be written independently with a BAL expectation attached. EIP-7 (DELEGATECALL) and EIP-2929 (warm/cold) are also in play conceptually, but both have been stable for years and their only consequence here is updating tests, which is already counted under "Patterns affecting pre-existing tests".	—

Show 20 zero-score criteria

Zero-score criteria (Checklist revision 2)
Criterion	Why this score	Notes
Added opcodes	No rationale recorded.	Blank cell read as zero because the published total proves it.
Added precompiles	No rationale recorded.	Blank cell read as zero because the published total proves it.
Modified precompiles	No rationale recorded.	Blank cell read as zero because the published total proves it.
Added system contracts	No rationale recorded.	Blank cell read as zero because the published total proves it.
Modified system contracts	No rationale recorded.	Blank cell read as zero because the published total proves it.
Blob gas accounting changes	No rationale recorded.	Blank cell read as zero because the published total proves it.
State gas accounting changes	No rationale recorded.	Blank cell read as zero because the published total proves it.
New EVM gas refund	No rationale recorded.	Blank cell read as zero because the published total proves it.
New transaction types	No rationale recorded.	Blank cell read as zero because the published total proves it.
New or modified transaction validity mechanisms	No rationale recorded.	Blank cell read as zero because the published total proves it.
New block / header fields	No rationale recorded.	Blank cell read as zero because the published total proves it.
Encoding changes (RLP/SSZ)	No rationale recorded.	Blank cell read as zero because the published total proves it.
Block syncing changes	No rationale recorded.	Blank cell read as zero because the published total proves it.
New fork activation mechanism	No rationale recorded.	Blank cell read as zero because the published total proves it.
Engine API changes	No rationale recorded.	Blank cell read as zero because the published total proves it.
Transition-tool interface changes	No rationale recorded.	Blank cell read as zero because the published total proves it.
New invariant on pre-existing tests	No rationale recorded.	Blank cell read as zero because the published total proves it.
New test-framework primitives	No rationale recorded.	Blank cell read as zero because the published total proves it.
Performance risks	No rationale recorded.	Blank cell read as zero because the published total proves it.
Cryptography	No rationale recorded.	Blank cell read as zero because the published total proves it.

Assessment provenance

Rubric: Checklist revision 2 · ethspecs/pm@3d8c0128c5
Evaluator: STEEL team · ethspecs/pm complexity_assessments
Source record: Open pull request #114: Add EIP-2488 complexity assessment · checklist at db669a2c21 · updated 2026-08-18
blob a62792dae1 · sha256 66c8591d137a
Research record: research/tasks/09-hegota-human-assessment-snapshot/outputs/assessments/eip-2488.yaml · sha256 5e1af322ebac

Both assessments applied Checklist revision 2 (28 criteria) to EIP-2488 in Hegotá. Δ is LLM minus Human.

Using the latest scored LLM evaluation for this checklist: 2026-08-26 · spec 2026-08-25 · ac450a4ab2. The Human and LLM assessments may use different spec revisions.

LLM10Low

Human13Medium

Δ total−3Tiers differ: Low vs Medium

Criteria24/28agree exactly · 3 differ by 1 · 1 differ by 2+

Complexity profiles side by side

LLM

Human

Largest disagreements: Patterns affecting pre-existing tests (−2), EVM Gas rule changes (−1), State-access ordering within opcode execution (−1), Security risks (+1)

Show differences only (4 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	3	−2	Differ by 2+	Show rationale LLM Existing tests that exercise CALLCODE across the fork must be updated, but the affected set is the narrow subset centered on one opcode, matching the minor-subset anchor. Human Major subset across diverse categories. CALLCODE appears in 63 hand-written test files and 353 files under `tests/ported_static/` in `execution-specs`. The ported static corpus is exactly the "static, multiple forks" case level 3 names: those tests were ported to run across every fork, so each one needs a fork-gated expectation once CALLCODE stops working.
EVM Gas rule changes	0	1	−1	Differ by 1	Show rationale LLM No gas-accounting change is specified, so the zero anchor applies. Whether existing CALLCODE charging remains in force is a material specification gap recorded separately. Human Existing gas accounting mechanism is updated. CALLCODE today carries the full CALL-family dynamic cost: base, cold/warm account access under EIP-2929, the value-transfer and new-account surcharges, memory expansion for the argument and return regions, and the 63/64 stipend reservation. The assumed behaviour is that the target is never warmed and no gas is consumed at all — the opcode pops its arguments, pushes 0, and charges nothing. That is the reading to specify, and it needs stating exactly, because the EIP's one-line specification says only that the instruction "always returns 0".
State-access ordering within opcode execution	0	1	−1	Differ by 1	Show rationale LLM The proposal does not specify a change to state-access or gas-charge ordering within CALLCODE, so the zero anchor applies on the sealed text. Human A single opcode's state access changes — it disappears. Under the assumed behaviour above, CALLCODE stops touching the target account entirely, so the target is no longer warmed for subsequent opcodes under EIP-2929 and no longer contributes an entry to the block-level access list. Both are observable, so the removal has to be tested rather than assumed.
Security risks	2	1	+1	Differ by 1	Show rationale LLM The modified opcode has a limited interaction surface but changes assumptions for contracts that execute it, with acknowledged potential breakage and no completed security analysis. That warrants targeted review rather than the self-contained score-1 treatment. Human Self-contained and validatable in isolation. Contracts that still call CALLCODE will break, but the failure is a returned 0 rather than an exceptional halt, so callers retain the chance to handle it. No existing invariant outside the opcode itself is altered.
Added opcodes	0	0	0	Agree	Show rationale LLM No new opcode is introduced. Human No rationale recorded.
Modified opcodes	3	3	0	Agree	Show rationale LLM A pre-existing opcode is deprecated and its non-gas behavior is modified, which exactly matches the score-3 anchor. Human CALLCODE (0xf2) is deprecated: its behaviour is replaced with an unconditional failure return.
Added precompiles	0	0	0	Agree	Show rationale LLM No precompile is added. Human No rationale recorded.
Modified precompiles	0	0	0	Agree	Show rationale LLM No pre-existing precompile behavior or gas accounting is modified. Human No rationale recorded.
Added system contracts	0	0	0	Agree	Show rationale LLM No system contract is added. Human No rationale recorded.
Modified system contracts	0	0	0	Agree	Show rationale LLM No direct or package-grounded indirect modification of a system contract is specified. Human No rationale recorded.
Blob gas accounting changes	0	0	0	Agree	Show rationale LLM No blob-gas accounting mechanism is introduced or updated. Human No rationale recorded.
State gas accounting changes	0	0	0	Agree	Show rationale LLM No state-gas cost, charging site, budget, reservoir, or spill rule is changed. Human No rationale recorded.
New EVM gas refund	0	0	0	Agree	Show rationale LLM No new EVM gas refund is specified. Human No rationale recorded.
New transaction types	0	0	0	Agree	Show rationale LLM No transaction type is introduced. Human No rationale recorded.
New or modified transaction validity mechanisms	0	0	0	Agree	Show rationale LLM Existing transaction validity and intrinsic gas calculation are not modified. Human No rationale recorded.
New block / header fields	0	0	0	Agree	Show rationale LLM No new block or block-header field is introduced. Human No rationale recorded.
Encoding changes (RLP/SSZ)	0	0	0	Agree	Show rationale LLM No RLP, SSZ, or other transaction/block/interface encoding change is introduced. Human No rationale recorded.
Block syncing changes	0	0	0	Agree	Show rationale LLM No block encoding or RLP validation mechanism requiring sync testing is introduced. Human No rationale recorded.
New fork activation mechanism	0	0	0	Agree	Show rationale LLM The fork changes opcode semantics without modifying state or an internal variable at the activation block, so it does not meet the nonzero anchor. Human No rationale recorded.
Engine API changes	0	0	0	Agree	Show rationale LLM No Engine API field, endpoint, or communication mechanism is introduced. Human No rationale recorded.
Transition-tool interface changes	0	0	0	Agree	Show rationale LLM No transition-tool interface field or mechanism is specified. Human No rationale recorded.
New invariant on pre-existing tests	0	0	0	Agree	Show rationale LLM Tests unrelated to this EIP gain no additional invariant or mechanically applied assertion. Human No rationale recorded.
New test-framework primitives	0	0	0	Agree	Show rationale LLM The specified result and fork boundary can be exercised with ordinary opcode-result tests; no new expectation, modifier, or helper is required by the package. Human No rationale recorded.
Performance risks	0	0	0	Agree	Show rationale LLM No new mechanism requiring performance validation is introduced; the specified path is a localized forced result. Human No rationale recorded.
Edge/boundary conditions	1	1	0	Agree	Show rationale LLM The proposal introduces one explicit activation boundary at which the same opcode changes from its prior behavior to forced failure. Human One boundary-prone mechanism: the always-fail path. Cases are that the opcode still pops the correct number of stack items and pushes 0, that memory arguments are not expanded, that the target stays cold, and that gas is unchanged across the call. Small, fixed set.
Cryptography	0	0	0	Agree	Show rationale LLM No cryptographic mechanism or cryptographic functionality is added or modified. Human No rationale recorded.
Cross-EIP interactions	1	1	0	Agree	Show rationale LLM There is one explicit, limited interaction with EIP-7. The proposal relies on DELEGATECALL as the historical replacement context but does not modify its specified behavior, so the interaction remains independently testable for the most part. Human Interacts with one other EIP in a limited way, and can be tested independently for the most part: EIP-7928 (block-level access lists) — whether a failed CALLCODE still contributes the target to the BAL is consensus-observable and needs settling, but CALLCODE's own cases can be written independently with a BAL expectation attached. EIP-7 (DELEGATECALL) and EIP-2929 (warm/cold) are also in play conceptually, but both have been stable for years and their only consequence here is updating tests, which is already counted under "Patterns affecting pre-existing tests".
Unspecified behavior requiring cross-client consensus	2	2	0	Agree	Show rationale LLM Constructible CALLCODE cases cannot be baselined from the text until clients agree on the localized operational details surrounding the forced result. The uncertainty concerns one opcode, so score 2 fits better than the broad or newly observable score-3 condition. Human Left undetermined by the specification: whether gas is charged for the no-op call, whether the target is warmed under EIP-2929, whether value is transferred, whether the target appears in the block-level access list, whether memory arguments are still expanded, and whether the 1024 call-frame depth limit is still checked or a depth level still consumed. Clients must agree on all of these before tests can be baselined. Localized to one opcode, so 2 rather than 3.

Compare EIP-2488 with other assessments All Hegotá 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 · Checklist revision 2 only
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 · Checklist revision 2 only
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 · Checklist revision 2 only
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 · Checklist revision 2 only
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 · Checklist revision 2 only
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.