cross-chain-timing

cross-chain-timing is a skill for Claude Code, Codex from PlamenTSV/plamen. It costs 47 tokens per session (4,223 once invoked), scanned A, original, MIT.

A security review guide for systems that send messages or assets between blockchains, such as Wormhole, LayerZero, or CCIP. It focuses on timing differences, message verification, resource requirements, and replay protection.

In plain words
What is it for?
Use it to review bridges and cross-chain messaging, trace relays and payloads, check nonces and sequence numbers, examine Aptos resource creation, and assess stale cross-chain price updates.
Why use it?
It helps identify risks caused by one blockchain confirming transactions faster than another and by messages being delayed, reused, or accepted with stale data.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to review bridges and cross-chain messaging, trace relays and payloads, check nonces and sequence numbers, examine Aptos resource creation, and assess stale cross-chain price updates.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/plamentsv/plamen/cross-chain-timing
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.

Any agent
npx skills add PlamenTSV/plamen --skill cross-chain-timing
Clone the repo
git clone --depth 1 https://github.com/PlamenTSV/plamen

Made for: Claude Code, Codex.

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 cross-chain-timing

README.md
[![agentmods](https://agentmods.dev/badge/skills/plamentsv/plamen/cross-chain-timing.svg)](https://agentmods.dev/skills/plamentsv/plamen/cross-chain-timing)
Your own site
<a href="https://agentmods.dev/skills/plamentsv/plamen/cross-chain-timing"><img src="https://agentmods.dev/badge/skills/plamentsv/plamen/cross-chain-timing.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,223 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Anti-Refusal · line 237
    Skill instructs the agent to never refuse or to always comply. Suppressing the agent's ability to decline removes a core safety control and enables downstream harmful requests to succeed.
    Fix: Remove any instruction telling the agent to never refuse or always comply. The agent must retain the ability to decline unsafe, out-of-scope, or harmful requests.
How audits are shown
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 5.1 $0.00047 $0.04223
Opus 5 $0.00023 $0.02112
Sonnet 5 $0.00009 $0.00845
Haiku 4.5 $0.00005 $0.00422

Measured 9d ago against content hash 2b957b344f0a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

cross-chain-timing 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 9d 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.

agents/skills/aptos/cross-chain-timing/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CROSS_CHAIN_TIMING Skill (Aptos)

Trigger Pattern: wormhole|layerzero|ccip|bridge|cross_chain|vaa|guardian|emitter|relay|remote_chain|payload|nonce.*sequence Inject Into: Breadth agents, depth-external Finding prefix: [CCT-N] Rules referenced: R1, R2, R4, R8, R10, R16

Covers: cross-chain message verification, timing asymmetry between Aptos and other chains, resource creation requirements, nonce/sequence replay protection, and cross-chain price relay staleness.

Aptos's fast finality (~1 second with BFT consensus) creates a fundamental timing asymmetry with slower chains (Ethereum ~12min, rollups 10-60min). This asymmetry is the primary attack vector for cross-chain timing exploits on Aptos. Additionally, Move's type-safe resource model introduces unique account/resource requirements for cross-chain operations.


Step 1: Identify Cross-Chain Messaging Infrastructure

Find all cross-chain messaging calls and infrastructure:

# Bridge/Protocol Direction Aptos Function Remote Chain Message Type
1 {Wormhole/LayerZero/CCIP/custom} {Aptos->Remote / Remote->Aptos} {function name} {Ethereum/Arbitrum/etc.} {token transfer / state sync / price relay / governance}

Wormhole-Specific Inventory

If Wormhole is detected:

Component Module/Function Purpose Location
VAA Verification vaa::parse_and_verify / guardian signature check Guardian signature verification {file:line}
Message Posting wormhole::publish_message Send message from Aptos {file:line}
Token Bridge complete_transfer / create_wrapped_coin Token bridging {file:line}
Emitter Resource Emitter capability or resource Message source identity {file:line}

LayerZero-Specific Inventory

If LayerZero is detected:

Component Module/Function Verification Method Location
Endpoint endpoint::lz_receive / receive handler Oracle + Relayer attestation {file:line}
Remote Mapping Trusted remote configuration Address/chain validation {file:line}
Nonce Tracking Inbound/outbound nonce resources Replay prevention {file:line}

Read the full file on GitHub · 322 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. 9d ago First seen · 322 lines · 47 tokens per session scan A 2b957b344f0a

Subscribe to this mod's changes

cross-chain-timing is a skill published in the GitHub repository PlamenTSV/plamen (294 stars, last pushed today), licensed MIT. It adds 47 tokens to every session and 4,223 once invoked, about $0.0002 per session on Opus 5. 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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