specref-execution-seam-scope

specref-execution-seam-scope is an agent for coding agents from Verified-zkEVM/evm-asm. It costs 0 tokens per session (4,101 once invoked), scanned A, original, MIT.

A design note for replacing a placeholder in SpecRef, a formal implementation of Ethereum’s execution rules, with a real link to execution. An execution seam is the defined boundary where that link is supplied.

In plain words
What is it for?
Planning verification of state-less Ethereum payloads, including Merkle-Patricia Trie checks and post-state-root validation.
Why use it?
The placeholder currently treats execution as always successful, so validation can disagree with the Ethereum reference rules, especially for invalid fixtures.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/verified-zkevm/evm-asm/specref-execution-seam-scope
Clone the repo
git clone --depth 1 https://github.com/Verified-zkEVM/evm-asm

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for specref-execution-seam-scope

README.md
[![agentmods](https://agentmods.dev/badge/agents/verified-zkevm/evm-asm/specref-execution-seam-scope.svg)](https://agentmods.dev/agents/verified-zkevm/evm-asm/specref-execution-seam-scope)
Your own site
<a href="https://agentmods.dev/agents/verified-zkevm/evm-asm/specref-execution-seam-scope"><img src="https://agentmods.dev/badge/agents/verified-zkevm/evm-asm/specref-execution-seam-scope.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,101 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.04101
Opus 5 $0.00000 $0.02050
Sonnet 5 $0.00000 $0.00820
Haiku 4.5 $0.00000 $0.00410

Measured 5d ago against content hash 7f2c63e6f7e8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

specref-execution-seam-scope scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

docs/agents/specref-execution-seam-scope.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SpecRef execution seam: scope and decomposition

Scoping document for bead evm-asm-s1d19 (P0): replace SpecRef's placeholder executeAlwaysOk with a real ExecutionSeam, so that verify_stateless_new_payload's successful_validation verdict matches execution-specs @ bd8c673 ([email protected]) on every fixture — including the ~974 succ=0 EEST fixtures where SpecRef currently diverges (issue #10141). Realizes obligations #7 (MPT verification of the pre-state witness) and #8 (post-state root), both of which sit behind the stubbed seam today.

Companion to the evm-asm-n9rtz v0.5.0 audit (docs/agents/specref-v050-audit.md); the boundary with n9rtz is recorded in §5.

1. The gap

EvmAsm/Stateless/SpecRef/Stateless.lean cuts the port of stateless.py::verify_stateless_new_payload at the call to execute_new_payload_request (stateless.py:378 in the v0.4.0 line numbering; the function is unchanged at bd8c673). Everything above the cut (chain-config validation, header-chain validation, witness DB assembly, NPR root, SSZ shell) is a real port; the call itself is the parameter execute : ExecutionSeam, defaulting to executeAlwaysOk := fun _ => .ok (). Consequences:

  • successfulValidation is always true, so SpecRef wrongly accepts every block whose real EVM execution fails.
  • The pre-state witness is assembled (build_node_db, keccak-keyed) but never authenticated against parent_header.stateRoot — MPT witness verification (obligation #7) never happens.
  • The post-state root is never recomputed or compared to header.state_root (obligation #8).
  • scripts/eest-specref-check.sh can gate only the pre-execution regions (root, tail); the verdict byte (succ) is explicitly ungated.

2. What the seam must contain (execution-specs @ bd8c673)

The Python call graph below the cut, with sizes (lines at bd8c673, src/ethereum/forks/amsterdam/):

Layer Source Size Content
Seam entry execution_engine/new_payload.py::execute_new_payload_request 169 empty-tx check; block-hash check; versioned-hash check; payload→Block; execute_block
Payload→header/block execution_engine/validation_helpers.py 106 _payload_header / _payload_block (needs unsecured trie roots over txs/withdrawals, compute_requests_hash, BAL keccak)
Block shell fork.py::execute_block (+validate_header, check_transaction, receipts, system txs) ~1,258 RLP size cap, header validation, apply_body, eight post-execution root/gas/bloom checks incl. state_root
Witness reads witness_state.py (WitnessState methods) 307 get_account_optional / get_storage / get_code / account_has_storage / compute_state_root_and_trie_changes
Witness trie incremental_mpt.py 1,040 read side: compact_to_nibbles, _decode_witness_node, _resolve_child_ref, decode_witness_to_mpt; write side: mpt_set/mpt_delete/mpt_root, node encoding
State tracking state_tracker.py, block_access_lists.py 928 + 744 BlockState/TransactionState journaling, BAL builder, EIP-8037 state-gas hooks
Transactions transactions.py 1,078 envelope decoding, recover_sender (via supplied public keys), intrinsic costs, EIP-8037 TX_MAX_GAS_LIMIT
EVM vm/ (interpreter.py, gas.py, instructions/*, eoa_delegation.py, memory.py, stack.py, runtime.py, exceptions.py) ~5,900 the interpreter and all 149 opcodes, incl. CALL/CREATE family, EIP-7702 one-hop delegation, EIP-8037 two-dimensional gas
Precompiles vm/precompiled_contracts/ ~2,300 all 20: ecrecover, sha256, ripemd160, identity, modexp, bn128 (3), blake2f, KZG point-eval, bls12-381 (7+), p256verify

Read the full file on GitHub · 222 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 222 lines · 0 tokens per session scan A 7f2c63e6f7e8

Subscribe to this mod's changes

specref-execution-seam-scope is an agent published in the GitHub repository Verified-zkEVM/evm-asm (55 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,101 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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