FabTally Decode — MCP server

Developer on-chain decoding reads that turn raw EVM bytes into human-readable JSON — the capability buried inside $49-999/mo RPC plans. Fronts the Decode HTTP API at https://decode.fabtally.com. Holds no private key.

Tools (all paid; a call with no payment returns the decoded x402 402 challenge)

Tool	Price	What it does
decode_log	$0.003	Flagship. Decode event LOGS to JSON. {chain, tx_hash} decodes every log in a tx, or {chain, address, topics[], data} a single log; optional abi. Returns event name + canonical signature + named/typed args — handling tuple/array/nested params, anonymous events, indexed vs non-indexed. Resolves ABI via Sourcify/Blockscout + 4byte when none is given.
decode_calldata	$0.002	Decode a function call. {chain, to?, data, abi?} → selector resolved to a function signature (provided ABI / verified source / 4byte.directory) + fully decoded typed arguments.
selector_lookup	$0.001	Resolve a 4-byte function selector (0x+8 hex) or a 32-byte event topic (0x+64 hex) to human signature(s) via 4byte.directory + openchain.xyz, with a verified flag.
abi_fetch	$0.002	Fetch a contract's verified ABI + metadata (Sourcify/Blockscout) + verification status + full proxy-implementation resolution (EIP-1967/1822/OZ-legacy/beacon) — returns the implementation ABI for proxies. Args: address, chain.

Chains: ethereum, base, arbitrum, optimism, polygon, bsc.

Every tool also accepts an optional x_payment (base64 x402 payload) that is forwarded as the X-PAYMENT header to settle the call and return the real result. Humans can instead prepay by card and use an X-FabTally-Key credit key against the HTTP API.

Transports

• stdio (portable): npx fabtally-decode-mcp (bin: fabtally-decode-mcp)
• streamable-http (hosted): https://decode.fabtally.com/mcp

Config: FABTALLY_DECODE_BASE (default https://decode.fabtally.com).

Read-only, keyless, stateless, descriptive. Operated by Sunstone Soft (fabtally.com). Not a security guarantee or financial advice.