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

1. Configure credential/binding for repeatable auth:

- uxc auth credential set etherscan-mcp --auth-type bearer --secret-env ETHERSCANAPIKEY - 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

1. 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

1. 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

1. 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

1. Run -h on the specific tool before the first real call.
2. Prefer one chain/address/token at a time before broadening the scope.
3. 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 <operation> ... is equivalent to uxc https://mcp.etherscan.io/mcp <operation> ....
• 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 ETHERSCANAPIKEY

• 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 <operation> -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