FabTally Decode MCP Server

io.github.zvmzaretsky/onchain-decode

answering

FabTally Decode is answering right now. Last checked 6 min ago. It exposes 4 tools. Last commit 1 Aug 2026.

Decode EVM bytes to JSON: event-log decoder, calldata explainer, selector lookup, ABI fetch.

Uptime history 43 hours of history

43 hours agonow

100.0%

Uptime 24h

91 of 91 checks

Tools

read from the server

129 ms

Response time

average over 24h

Stars

last commit 1 Aug 2026

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 6 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add onchain-decode --transport http https://decode.fabtally.com/mcp

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "onchain-decode": {
      "url": "https://decode.fabtally.com/mcp"
    }
  }
}

~/.codex/config.toml

[mcp_servers.onchain-decode]
url = "https://decode.fabtally.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "onchain-decode": {
      "url": "https://decode.fabtally.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "mcpServers": {
    "onchain-decode": {
      "url": "https://decode.fabtally.com/mcp"
    }
  }
}

Available tools 4

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

decode

decode_calldata

PAID $0.002 (x402, USDC on Base). Decode a contract function call. Give {chain, to?, data, abi?}; get the 4-byte selector resolved to a function signature (via provided ABI, the verified contract source, or 4byte.directory) plus fully decoded, typed arguments (tuples/arrays/nested included). Without payment returns the x402 challenge.

decode_log

PAID $0.003 (x402, USDC on Base). FLAGSHIP: decode EVM event LOGS to human-readable JSON. Give {chain, tx_hash} to decode every log in a transaction, OR {chain, address, topics[], data} for a single log; optional {abi}. Returns each event's name, canonical signature and named/typed args — correctly handling tuple/array/nested params, anonymous events, and indexed vs non-indexed. Resolves the ABI via Sourcify/Blockscout + 4byte event signatures when none is supplied. Without payment returns the x402 challenge; pass x_payment to settle.

abi

abi_fetch

PAID $0.002 (x402, USDC on Base). Fetch the verified ABI + metadata for a contract. Give {address, chain}; get the ABI JSON, verification status/source (Sourcify or Blockscout), the callable function/event signatures, and full proxy-implementation resolution (EIP-1967/1822/OZ-legacy/beacon) — returning the implementation's ABI when it's a proxy. Without payment returns the x402 challenge; pass x_payment to settle.

selector

selector_lookup

PAID $0.001 (x402, USDC on Base). Resolve a 4-byte function selector (0x + 8 hex) OR a 32-byte event topic hash (0x + 64 hex) to its human-readable signature(s) via 4byte.directory + openchain.xyz. Returns all matches (selectors can collide) with a verified flag. Without payment returns the x402 challenge; pass x_payment to settle.

Endpoints

URL	Transport	State	Latency	Checked
https://decode.fabtally.com/mcp	streamable-http	answering	170 ms	6 min ago

FabTally Decode — questions

Answers built from our own checks of this server.

What can FabTally Decode do?

It exposes 4 tools, read directly from the server on our last check. Among them: abi_fetch, decode_calldata, decode_log, selector_lookup. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is FabTally Decode working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 91 of 91 checks got a reply (100.0%), average response time 129 ms. The bar chart above shows every period we have measured.

How do I connect FabTally Decode?

Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does FabTally Decode need an API key?

No. FabTally Decode completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 4 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is FabTally Decode?

It answers our handshake in 129 ms on average, which is faster than 78% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.

Is FabTally Decode open source?

Yes — it is published under the MIT licence, written in JavaScript and 0 stars on GitHub. The source link is on this page, so you can read exactly what it does with your data before you connect it.