make_app_closeout_txn

THE RISK

High Risk

A 'close out' transaction on a blockchain application executes an on-chain operation that removes or exits the caller from an application/contract, committing state changes to the blockchain. This is an irreversible operation that triggers external blockchain execution. While it has destructive qualities (closing out an application relationship), the primary action is executing a blockchain transaction.

From the tool's definition Create an application close out transaction

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

HOW TO CONTROL MAKE_APP_CLOSEOUT_TXN

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 make_app_closeout_txn:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "make_app_closeout_txn": {
      "limits": [
        {
          "counter": "make_app_closeout_txn_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

make_app_closeout_txn 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.

Create a free account and register BNB Chain MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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All 1240 BNB Chain MCP tools →

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Go deeper

High-risk tools in BNB Chain MCP → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the make_app_closeout_txn tool do? +

Create an application close out transaction. 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 make_app_closeout_txn? +

Register the BNB Chain MCP server in PolicyLayer and add a rule for make_app_closeout_txn: 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 make_app_closeout_txn? +

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

Can I rate-limit make_app_closeout_txn? +

Yes. Add a rate_limit block to the make_app_closeout_txn 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 make_app_closeout_txn completely? +

Set action: deny in the PolicyLayer policy for make_app_closeout_txn. 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 make_app_closeout_txn? +

make_app_closeout_txn 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.

GOVERN BNB CHAIN →

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

// WHAT MAKE_APP_CLOSEOUT_TXN ON BNB CHAIN MCP DOES

// THE RISK

// HOW TO CONTROL MAKE_APP_CLOSEOUT_TXN

// EXPLORE