A lookup tool for public records on Ethereum-compatible blockchains, including contracts, transactions, balances, tokens, and event logs. It uses one Etherscan API across many supported networks.

Use it to inspect contract code and interfaces, trace transactions, check balances, read token details, find contract creation, estimate gas, and verify contracts.

It avoids opening separate block-explorer websites or learning different APIs for each blockchain.

chainscan — Skill for Claude Code and Codex by avenoxai/avenoxskills

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 avenoxai/avenoxskills --skill chainscan

Clone the repo

git clone --depth 1 https://github.com/avenoxai/avenoxskills

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/avenoxai/avenoxskills/chainscan/github.svg)](https://agentmods.dev/skills/avenoxai/avenoxskills/chainscan)

Your own site

<a href="https://agentmods.dev/skills/avenoxai/avenoxskills/chainscan"><img src="https://agentmods.dev/badge/skills/avenoxai/avenoxskills/chainscan/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/avenoxai/avenoxskills/chainscan"><img src="https://agentmods.dev/badge/skills/avenoxai/avenoxskills/chainscan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 157 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,575 The whole file, excluding the scripts and references it only reads on demand.

Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00157	$0.03575
Opus 5.5	$0.00063	$0.01430
Sonnet 5.5	$0.00031	$0.00715
Haiku 4.5	$0.00016	$0.00358

Measured 2mo ago against content hash ab3687570478, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

chainscan scanned grade C with 2 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 2mo 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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -s "https://api.etherscan.io/v2/api?chainid=<CHAIN>&module=contract&action=getabi&address=<ADDR>&apikey={{vault:ETHERSCAN_API_KEY}}" | python3 -m json.tool

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s "https://api.etherscan.io/v2/api?chainid=<CHAIN>&module=contract&action=getabi&address=<ADDR>&apikey={{vault:ETHERSCAN_API_KEY}}" | python3 -m json.tool

skills/chainscan/SKILL.md · 267 lines

How it starts

The opening of the file, as written. The whole thing — 267 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Chainscan — Etherscan V2 unified explorer skill

Query any major EVM chain's block explorer via the Etherscan V2 unified API, with Foundry cast as a fallback for paid-tier endpoints. One Etherscan.io API key works across every supported chain through V2 — BscScan/PolygonScan/etc. keys do not work and are no longer needed.

Etherscan V1 was deprecated 2025-08-15. V2 is the only API path going forward.

Configuration

Base URL:        https://api.etherscan.io/v2/api
API key:         {{vault:ETHERSCAN_API_KEY}}
Auth pattern:    &apikey={{vault:ETHERSCAN_API_KEY}}
Chain selector:  &chainid=<id>   (REQUIRED on every call — no default)
Free tier:       3 req/sec, 100k req/day

Chain ID quick reference

Most-used chains:

Chain	chainid	Native	Default RPC
Ethereum mainnet	`1`	ETH	`https://eth.llamarpc.com`
BSC	`56`	BNB	`https://bsc-dataseed.binance.org`
Polygon	`137`	MATIC	`https://polygon-rpc.com`
Arbitrum One	`42161`	ETH	`https://arb1.arbitrum.io/rpc`
Optimism	`10`	ETH	`https://mainnet.optimism.io`
Base	`8453`	ETH	`https://mainnet.base.org`
Avalanche C-chain	`43114`	AVAX	`https://api.avax.network/ext/bc/C/rpc`
Sepolia	`11155111`	ETH	`https://ethereum-sepolia-rpc.publicnode.com`
Base Sepolia	`84532`	ETH	`https://sepolia.base.org`
Arbitrum Sepolia	`421614`	ETH	`https://sepolia-rollup.arbitrum.io/rpc`

Full list: see references/chains.md.

Free-tier endpoint availability

This is the most important table to internalize. Many endpoints are gated behind paid plans on non-Ethereum chains.

Endpoint	ETH (1)	Polygon (137)	Arbitrum (42161)	BSC (56)	Base (8453)	OP (10)	Avalanche (43114)
`getabi`	YES	YES	YES	YES	YES	YES	YES
`getsourcecode`	YES	YES	YES	YES	YES	YES	YES
`verifysourcecode`	YES	YES	YES	YES	YES	YES	YES
`checkverifystatus`	YES	YES	YES	YES	YES	YES	YES
`getcontractcreation`	YES	YES	YES	NO	NO	NO	NO
`balance`, `txlist`, `tokentx`, `getLogs`, gas, prices	YES	YES	YES	NO	NO	NO	NO

Read the full file on GitHub · 267 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2mo ago First seen · 267 lines · 157 tokens per session scan C ab3687570478

Subscribe to this mod's changes

chainscan is a skill published in the GitHub repository avenoxai/avenoxskills (112 stars, last pushed 19d ago), licensed MIT. It adds 157 tokens to every session and 3,575 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Claude Code Web3 and blockchain agent-skills ai-agents claude codex llm-tools

chainscan next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
chainscanavenoxai/avenoxskills	Skill	112	19d ago	MIT	C	157	Claude Code, Codex
alchemy-webhookshookdeck/webhook-skills	Skill	98	yesterday	MIT	A	51	Claude Code, Codex
fireblocks-webhookshookdeck/webhook-skills	Skill	98	yesterday	MIT	A	65	Claude Code, Codex
utila-webhookshookdeck/webhook-skills	Skill	98	yesterday	MIT	A	70	Claude Code, Codex
opensea-apickorhonen/claude-skills	Skill	24	1mo ago	MIT	A	42	Claude Code
blockchain-auditorckorhonen/claude-skills	Skill	24	1mo ago	MIT	B	80	Claude Code
crossmint-webhookshookdeck/webhook-skills	Skill	98	yesterday	MIT	A	88	Claude Code, Codex

chainscan