etherscan-mcp-skill

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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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NPX Install

npx skill4agent add holon-run/uxc etherscan-mcp-skill

Tags

Translated version includes tags in frontmatter

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 <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