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sign_typed_data

Sign typed data using EIP-712

How to control sign_typed_data ↓

AI agents invoke sign_typed_data to trigger actions in BNB Chain MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

High Risk

EIP-712 signing creates cryptographic signatures that can authorize on-chain transactions, token approvals, permit signatures, or smart contract interactions. While signing itself doesn't immediately execute a transaction, the resulting signature can be used to trigger financial transfers, approve token spending, or execute arbitrary contract calls.

From the tool's definition Sign typed data using EIP-712

Documented attack patterns abuse exactly the kind of access sign_typed_data gives an agent:

PolicyLayer is an MCP gateway — it sits between your AI agents and BNB Chain MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for sign_typed_data:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "sign_typed_data": {
      "limits": [
        {
          "counter": "sign_typed_data_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

sign_typed_data stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

  1. Create a free account and register BNB Chain MCP — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

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Go deeper

What does the sign_typed_data tool do? +

Sign typed data using EIP-712. It is categorised as a Execute tool in the BNB Chain MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on sign_typed_data? +

Register the BNB Chain MCP server in PolicyLayer and add a rule for sign_typed_data: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches BNB Chain MCP. Nothing to install.

What risk level is sign_typed_data? +

sign_typed_data is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit sign_typed_data? +

Yes. Add a rate_limit block to the sign_typed_data rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block sign_typed_data completely? +

Set action: deny in the PolicyLayer policy for sign_typed_data. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides sign_typed_data? +

sign_typed_data is provided by the BNB Chain MCP server (nirholas/bnbchain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every BNB Chain MCP tool call.

Deterministic rules across all 1240 BNB Chain MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

1240 BNB Chain MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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