Etherscan Mcp Skill

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name: etherscan-mcp-skill description: Use Etherscan MCP through UXC for address balance checks, token holder analysis, transaction inspection, and contract lookup tasks. Use when tasks need Etherscan MCP tools for onchain investigation with help-first schema inspection, bearer-key auth, and tier-aware read-first handling.

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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

1. Confirm endpoint and protocol with help-first probing: - uxc https://mcp.etherscan.io/mcp -h - expected unauthenticated behavior today: 401 Unauthorized 2. 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 3. 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 4. 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 5. 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

Inspect etherscan-mcp-cli -h after auth setup for the current full tool list. Etherscan can expand MCP tools independently of this wrapper skill.

Recommended Usage Pattern

1. Start from a read-only investigation goal: - balance or holdings for an address - holder concentration for a token - transaction inspection for a hash - source/metadata lookup for a contract 2. Run -h on the specific tool before the first real call. 3. Prefer one chain/address/token at a time before broadening the scope. 4. Parse the JSON envelope first, then inspect data.

Guardrails

Keep automation on JSON output envelope; do not rely on --text.

Parse stable fields first: ok, kind, protocol, data, error.

Use etherscan-mcp-cli as default command path.

etherscan-mcp-cli ... is equivalent to uxc https://mcp.etherscan.io/mcp ....

If unauthenticated probe or runtime call returns 401 Unauthorized:

- confirm auth binding matches endpoint with uxc auth binding match https://mcp.etherscan.io/mcp - confirm credential shape with uxc auth credential info etherscan-mcp - reset credential as bearer if needed: uxc auth credential set etherscan-mcp --auth-type bearer --secret-env ETHERSCAN_API_KEY

Use key=value only for simple scalar inputs.

Prefer positional JSON when an operation accepts nested objects, arrays, or optional flags that may evolve.

Do not assume tool argument names from memory; inspect -h first because Etherscan may revise MCP schemas independently of this skill.

Some MCP tools are tier-gated by Etherscan plan. Today getTokenInfo can return NOTOK with an API Pro upgrade message on non-Pro keys.

Treat verifySourceCode as a write-like action requiring explicit user confirmation.

References

Invocation patterns:

- references/usage-patterns.md

uxc is installed and available in PATH.

Network access to https://mcp.etherscan.io/mcp.

An Etherscan API key is available for authenticated calls.