Ethereum Transaction Builder MCP Server

An MCP (Model Context Protocol) server providing comprehensive Ethereum transaction capabilities including building, signing, decoding, and analysis for both legacy and EIP-1559 transactions. Its 15 documented tools cover transaction, decode, build, sign.

People connecting this server to Claude, Cursor, VS Code, or another MCP client. The project is written in HTML.

One of 5 MCP servers published from nirholas/ethereum-wallet-toolkit. Stars and repository activity are shared across all of them. See all 5 →

VERIFIED ACTIVE

LAST COMMIT 2026-08-17 · VERIFIED 2026-08-25

NOASSERTION · HTML · how we verify → /methodology

01 · Install Ethereum Transaction Builder

Claude Code

claude mcp add nirholas-ethereum-wallet-toolkit-transac -- uvx transaction-mcp-server

Claude Desktop / Cursor / VS Code - add to config

{
  "mcpServers": {
    "nirholas-ethereum-wallet-toolkit-transac": {
      "command": "uvx",
      "args": [
        "transaction-mcp-server"
      ]
    }
  }
}

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions

license no standard license detected - usage rights unclear; check the repo before commercial use

pypi package transaction-mcp-server - check the name against the project README before installing (PyPI has no namespace ownership)

registry namespace io.github.nirholas is GitHub-verified and matches the repo owner

03 · What Ethereum Transaction Builder can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

What you can build

With this server connected, an agent can validate transaction fields, compare two transactions, convert between wei, gwei, ether, and calculate maximum transaction cost.

Capability map

Tools grouped from the project's README - what Ethereum Transaction Builder lets an agent do.

Decode

3 tools - e.g. Decode a signed raw transaction; Decode an unsigned transaction; Decode transaction input data

decode_raw_transaction · decode_unsigned_transaction · decode_calldata

Build

2 tools - e.g. Build an unsigned transaction; Build and sign in one step

build_transaction · build_and_sign_transaction

Encode

2 tools - e.g. Encode ERC-20 transfer calldata; Encode arbitrary function call

encode_transfer · encode_function_call

Sign

1 tool - e.g. Sign a transaction with a private key

sign_transaction

Recover

1 tool - e.g. Recover signer from signed transaction

recover_transaction_signer

Estimate

1 tool - e.g. Estimate gas cost in ETH

estimate_transaction_cost

Validate

1 tool - e.g. Validate transaction fields

validate_transaction

Compare

1 tool - e.g. Compare two transactions

compare_transactions

04 · Who maintains Ethereum Transaction Builder

Ethereum Transaction Builder is maintained by nirholas. We track 66 MCP servers from nirholas - 65 actively maintained, 7,658 combined GitHub stars, oldest repo from Feb 2024. Full record: all servers from nirholas.

05 · Facts

repository: github.com/nirholas/ethereum-wallet-toolkit
category: other - actively maintained as of 2026-08-25.
registry: io.github.nirholas/transaction-mcp-server (active, first published 2026-01-20)
packages: pypi:transaction-mcp-server

06 · Ethereum Transaction Builder FAQ

Is Ethereum Transaction Builder still maintained?

Yes - as of 2026-08-25, its last commit was 2026-08-17. We re-verify nightly.

What can Ethereum Transaction Builder do?

With this server connected, an agent can validate transaction fields, compare two transactions, convert between wei, gwei, ether, and calculate maximum transaction cost.

How do I install Ethereum Transaction Builder?

Run `uvx transaction-mcp-server`. You can also paste the ready-made client config above.

Does Ethereum Transaction Builder run locally?

Yes - it's a stdio server: it runs on your machine (via uvx) with your user's permissions. Your data stays local unless the server itself calls external APIs.

07 · Alternatives to Ethereum Transaction Builder

Alternatives to Ethereum Transaction Builder

Maintained other servers if Ethereum Transaction Builder isn't the fit.

More MCP servers to compare · Ethereum Address Validator · UCAI · AI Connector For Revit · Nx MCP · Microsoft NuGet