etherscan-verification

etherscan-verification is a skill for Claude Code from sablier-labs/plugin-marketplace. It costs 67 tokens per session (929 once invoked), scanned A, original, MIT.

A guide for verifying deployed smart contracts on Etherscan-compatible blockchain explorers. Verification publishes matching source details so others can inspect a contract's code on the explorer.

In plain words
What is it for?
Use it to verify contracts with Foundry, handle proxy or factory deployments, and obtain constructor arguments from deployment data.
Why use it?
It explains the checks and commands needed when verification involves standard contracts, proxy contracts, factory-created contracts, or networks with different API support.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the web3 plugin — 4 skills shipped together

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 skills/sablier-labs/plugin-marketplace/etherscan-verification
Any agent
npx skills add sablier-labs/plugin-marketplace --skill etherscan-verification
Clone the repo
git clone --depth 1 https://github.com/sablier-labs/plugin-marketplace

Made for: Claude Code.

Or install web3, the plugin that ships this one along with the rest of its 4 skills.

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 etherscan-verification

README.md
[![agentmods](https://agentmods.dev/badge/skills/sablier-labs/plugin-marketplace/etherscan-verification.svg)](https://agentmods.dev/skills/sablier-labs/plugin-marketplace/etherscan-verification)
Your own site
<a href="https://agentmods.dev/skills/sablier-labs/plugin-marketplace/etherscan-verification"><img src="https://agentmods.dev/badge/skills/sablier-labs/plugin-marketplace/etherscan-verification.svg" alt="Measured on agentmods" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 929 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 5.1 $0.00067 $0.00929
Opus 5 $0.00034 $0.00464
Sonnet 5 $0.00013 $0.00186
Haiku 4.5 $0.00007 $0.00093

Measured 6d ago against content hash 84bfbcf7e3ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

etherscan-verification 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 6d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/extract_constructor_args.py), 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.

plugins/web3/skills/etherscan-verification/SKILL.md · 137 lines

How it starts

The opening of the file, as written. The whole thing — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

Contract verification on Etherscan-compatible explorers using Foundry's forge verify-contract. Covers standard verification, unsupported chains via Etherscan V2 API, proxy patterns, and factory-created contracts.

When to Use

  • Verify deployed smart contracts on Etherscan-compatible explorers
  • Verify proxy contracts (ERC1967, UUPS)
  • Verify factory-created contracts (CREATE2)
  • Extract constructor arguments from deployment data

Prerequisites

Requirement How to Get
Foundry ≥1.3.6 Run forge -V to check version
Contract address From deployment broadcast or user
Chain ID From explorer or network configuration
Explorer API key From Etherscan account (works for V2 multi-chain)
Source code Must match deployed bytecode exactly

Version Check

Before proceeding, verify Foundry version:

forge -V

Stop if version is below 1.3.6.

Verification Methods

Method 1: Standard (Native Support)

For chains Foundry supports natively:

FOUNDRY_PROFILE=optimized forge verify-contract \
  <CONTRACT_ADDRESS> \
  src/<Contract>.sol:<Contract> \
  --rpc-url <chain_name> \
  --verifier etherscan \
  --etherscan-api-key $ETHERSCAN_API_KEY \
  --watch

Method 2: Etherscan V2 API (Unsupported Chains on Foundry)

When Foundry shows "No known Etherscan API URL for chain X":

FOUNDRY_PROFILE=optimized forge verify-contract \
  <CONTRACT_ADDRESS> \
  src/<Contract>.sol:<Contract> \
  --verifier etherscan \
  --verifier-url "https://api.etherscan.io/v2/api?chainid=<CHAIN_ID>" \
  --etherscan-api-key $ETHERSCAN_API_KEY \
  --watch

Supported chains: https://docs.etherscan.io/supported-chains

Method 3: With Constructor Arguments

For contracts with constructor parameters:

FOUNDRY_PROFILE=optimized forge verify-contract \
  <CONTRACT_ADDRESS> \
  src/<Contract>.sol:<Contract> \
  --verifier etherscan \
  --verifier-url "https://api.etherscan.io/v2/api?chainid=<CHAIN_ID>" \
  --etherscan-api-key $ETHERSCAN_API_KEY \
  --constructor-args <ABI_ENCODED_ARGS> \
  --watch

Read the full file on GitHub · 137 lines

Files

What ships with it

4 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.

  1. 6d ago First seen · 137 lines · 67 tokens per session scan A 84bfbcf7e3ce

Subscribe to this mod's changes

etherscan-verification is a skill published in the GitHub repository sablier-labs/plugin-marketplace (7 stars, last pushed 2mo ago), licensed MIT. It adds 67 tokens to every session and 929 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 2026-08-31.

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