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bnbchain-mcp

bnbchain-mcp

Official
by bnb-chain
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Hybrid

write_contract

Interact with smart contracts on BNB Chain by calling state-changing functions. Specify contract address, ABI, function name, arguments, and network to execute write operations securely.

Instructions

Write data to a smart contract by calling a state-changing function

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "contractAddress": "<contractAddress>",
      "abi": "<abi>",
      "functionName": "<functionName>",
      "args": "<args>"
    },
    "name": "write_contract"
  }
}

Input Schema

NameRequiredDescriptionDefault
abiYesThe ABI of the smart contract function, as a JSON array
argsYesThe arguments to pass to the function
contractAddressYesThe address of the smart contract to interact with
functionNameYesThe name of the function to call on the contract
networkNoNetwork name (e.g. 'bsc', 'opbnb', 'ethereum', 'base', etc.) or chain ID. Supports others main popular networks. Defaults to BSC mainnet.bsc
privateKeyNoPrivate key of the sending account. Used only for transaction signing.0x5a2b7e4d9c8f1a3e6b0d2c5f4e3d2a1b0c9f8e7d6a5b4c3d2e1f0a9b8c7d6e5f4

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv1.0.0

TDQS

C2.9/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions 'state-changing function' which implies mutation, but doesn't cover critical aspects: transaction costs (gas), network confirmation times, irreversible nature of blockchain writes, authentication requirements (private key usage), or error handling. For a high-stakes write operation, this is insufficient transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that communicates the core purpose without unnecessary words. It's appropriately front-loaded with the essential action and target. Every word earns its place in this compact formulation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex blockchain write operation with 6 parameters, no annotations, and no output schema, the description is inadequate. It doesn't address transaction lifecycle, error scenarios, cost implications, or return values. Given the high-stakes nature of smart contract interactions and the rich sibling tool ecosystem, more contextual information is needed for safe and effective use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, providing complete parameter documentation. The description adds no additional parameter semantics beyond what's in the schema - it doesn't explain relationships between parameters (e.g., how ABI matches functionName), format requirements, or practical examples. With full schema coverage, the baseline of 3 is appropriate as the description doesn't enhance parameter understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('write data') and target ('smart contract') with the specific mechanism ('calling a state-changing function'), which distinguishes it from read-only operations like 'read_contract'. However, it doesn't explicitly differentiate from other state-changing tools like 'transfer_erc20' or 'approve_token_spending', which are more specific implementations of contract writes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a private key for signing), contrast with 'read_contract' for non-state-changing calls, or explain when to use more specialized tools like 'transfer_erc20' instead. This leaves the agent without contextual decision-making help.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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