Etherscan Mcp Skill

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.

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 <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 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 <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