build_event_topic
Builds an event topic signature based on event name and arguments
LABSCO SUMMARY
Keeping an explorer tab, an ABI file and a topic-hash calculator open next to the editor.
get_proxy is the tool that decides whether the rest of the session is wasted — the address you were handed is often not where the logic lives, and read_contract against the wrong one fails in a way that reads like a network problem. The read path is complete but literal: read_contract asks you to spell out inner struct types rather than infer them from the ABI it can already fetch.
What it is
An onchain read client with ten tools: contract state and metadata, event logs, transactions, token balances and blocks, each scoped to a named network.
What you get
- Contract state read by method with explicit input and output types, including the inner types of a tuple or nested struct
- The proxy address behind a contract, its ABI, and its verified source code
- Event logs for a network filtered by address, topic, optional topics and a block range
- An event topic signature built from the event name and its argument types, which is what the log filter needs
- Transaction history for an address, optionally narrowed to one contract, one method id or a starting block
- Full detail on a single transaction by hash, and on a block by number or hash
- Every token balance held by an address on a given network
Requirements
A Bankless API token in BANKLESS_API_TOKEN, and npx on your PATH.
Setup effort
One command plus a key — npx @bankless/onchain-mcp, then supply credentials
USE CASES
01
Reading state off a contract you did not deploy
Resolve the proxy first — the address you were handed often is not where the logic lives — then pull the ABI and call the method with its input and output types spelled out.
02
Tracing what an address has been doing
Pull the transaction history, optionally narrowed to one contract, method id or starting block, then open the transactions that matter and check what the address currently holds.
03
Pulling the logs for one kind of event
Build the topic signature from the event name and its argument types, then filter logs by address and block range around it.
04
Checking what a contract actually is before trusting it
Verified source next to the ABI answers what the methods do, not just what they are called — worth doing before read_contract, and before anything that spends.
10 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
get_abi
Gets the ABI for a given contract on a specific network
get_block_info
Gets detailed information about a specific block by number or hash
get_events
Fetches event logs for a given network and filter criteria
get_proxy
Gets the proxy address for a given network and contract
get_source
Gets the source code for a given contract on a specific network
get_token_balances_on_network
Gets all token balances for a given address on a specific network
get_transaction_history_for_user
Gets transaction history for a user and optional contract
get_transaction_info
Gets detailed information about a specific transaction
read_contract
Read contract state from a blockchain. important:
In case of a tuple, don't use type tuple, but specify the inner types (found in the source) in order. For nested structs, include the substructs types.
Example: struct DataTypeA { DataTypeB b; //the liquidity index. Expressed in ray uint128 liquidityIndex; }
struct DataTypeB { address token; }
results in outputs for function with return type DataTypeA (tuple in abi): outputs: [{"type": "address"}, {"type": "uint128"}]
BEFORE YOU INSTALL
What to know first
Tools you get
10 tools when we connected.
Requires
- npx on PATH
- BANKLESS_API_TOKEN in your environment
Where it runs
The documented client runs the server on your machine.
CONTEXT COST
Light Standing cost
Rated by the size of the 10 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Server setup
TERMINAL
npx @bankless/onchain-mcpMCP Clients
Any MCP client
ANY MCP CLIENT · JSON
{
"mcpServers": {
"bankless": {
"command": "npx",
"args": [
"@bankless/onchain-mcp"
],
"env": {
"BANKLESS_API_TOKEN": "<YOUR_BANKLESS_API_TOKEN>"
}
}
}
}
