What is etherscan-mcp-skill?

A connection to Etherscan, a website and data service for inspecting activity on Ethereum and related networks. It provides MCP tools for reading blockchain addresses, transactions, tokens, and contracts.

Use it to check address balances, analyze token holders, inspect transactions, and look up smart contracts.

It gives an agent structured access to common blockchain investigations instead of requiring manual browsing or custom requests. Authenticated calls require an Etherscan API key.

etherscan-mcp-skill — Skill for Codex by holon-run

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 holon-run/uxc --skill etherscan-mcp-skill

Clone the repo

git clone --depth 1 https://github.com/holon-run/uxc

Made for: 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/holon-run/uxc/etherscan-mcp-skill.svg)](https://agentmods.dev/skills/holon-run/uxc/etherscan-mcp-skill)

Your own site

<a href="https://agentmods.dev/skills/holon-run/uxc/etherscan-mcp-skill"><img src="https://agentmods.dev/badge/skills/holon-run/uxc/etherscan-mcp-skill.svg" alt="Measured on agentmods" height="20"></a>

Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,057 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.

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	$0.00062	$0.01057
Opus 5	$0.00031	$0.00528
Sonnet 5	$0.00012	$0.00211
Haiku 4.5	$0.00006	$0.00106

Measured 7d ago against content hash 4dba039d57cf, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

etherscan-mcp-skill 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 7d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/etherscan-mcp-skill/SKILL.md · 99 lines

How it starts

The opening of the file, as written. The whole thing — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Etherscan MCP Skill

Use this skill to run Etherscan MCP operations through uxc.

Reuse the uxc skill for shared protocol discovery, output parsing, and generic auth/binding flows.

Prerequisites

uxc is installed and available in PATH.
Network access to https://mcp.etherscan.io/mcp.
An Etherscan API key is available for authenticated calls.

Core Workflow

Confirm endpoint and protocol with help-first probing:
- uxc https://mcp.etherscan.io/mcp -h
- expected unauthenticated behavior today: 401 Unauthorized
Configure credential/binding for repeatable auth:
- uxc auth credential set etherscan-mcp --auth-type bearer --secret-env ETHERSCAN_API_KEY
- uxc auth credential set etherscan-mcp --auth-type bearer --secret-op op://Engineering/etherscan/api-key
- uxc auth binding add --id etherscan-mcp --host mcp.etherscan.io --path-prefix /mcp --scheme https --credential etherscan-mcp --priority 100
Use fixed link command by default:
- command -v etherscan-mcp-cli
- If missing, create it: uxc link etherscan-mcp-cli https://mcp.etherscan.io/mcp
- etherscan-mcp-cli -h
Inspect operation schema before execution:
- etherscan-mcp-cli balance -h
- etherscan-mcp-cli tokenTopHolders -h
- etherscan-mcp-cli getContractAbi -h
- etherscan-mcp-cli transaction -h
Prefer read operations first, then any workflow that could trigger heavy data pulls or follow-up automation.

Capability Map

Address investigation:
- balance
- tokenHoldings
- fundedBy
- getAddressMetadata
Token holder analysis:
- balanceERC20
- balanceERC20Historical
- tokenTopHolders
- getTokenInfo
Transaction investigation:
- txList
- internalTxsByAddress
- erc20Transfers
- erc721Transfers
- erc1155Transfers
- transaction
- checkTransaction
Contract research:
- getContractAbi
- getContractSourceCode
- getContractCreation
Verification:
- verifySourceCode
- checkVerifyStatus

Read the full file on GitHub · 99 lines

Files

What ships with it

3 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.

7d ago First seen · 99 lines · 62 tokens per session scan A 4dba039d57cf

Subscribe to this mod's changes

etherscan-mcp-skill is a skill published in the GitHub repository holon-run/uxc (113 stars, last pushed 29d ago), licensed MIT. It adds 62 tokens to every session and 1,057 once invoked, about $0.0003 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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