ugf_vault_build_tx · Universal Gas Framework MCP Server MCP

WHAT IT DOES

What ugf_vault_build_tx does on Universal Gas Framework MCP Server

AI agents invoke ugf_vault_build_tx to trigger actions in Universal Gas Framework MCP Server. 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.

WHY IT NEEDS A POLICY

Why ugf_vault_build_tx needs a policy

This tool builds a blockchain payment transaction intended to be signed and broadcast, directly initiating a financial operation (vault payment). While it only builds the unsigned transaction, it is a critical step in executing a cross-chain financial transaction and triggers the payment flow.

From the tool's definition Build unsigned EIP-1559 vault payment tx for local signing + broadcast. Returns {to, data, value, chainId, gasLimit, nonce, type, maxFeePerGas, maxPriorityFeePerGas} — all BigInts as strings. Agent signs + broadcasts, then calls ugf_vault_submit_signed.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ugf_vault_build_tx Rate-limited

ugf_vault_build_tx 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.

View as policy code

policy.json

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

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Universal Gas Framework MCP Server, so you can run agents against it safely.

FAQ

Questions about ugf_vault_build_tx

What does the ugf_vault_build_tx tool do? +

Build unsigned EIP-1559 vault payment tx for local signing + broadcast. Returns {to, data, value, chainId, gasLimit, nonce, type, maxFeePerGas, maxPriorityFeePerGas} — all BigInts as strings. Agent signs + broadcasts, then calls ugf_vault_submit_signed. It is categorised as a Execute tool in the Universal Gas Framework MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on ugf_vault_build_tx? +

Register the Universal Gas Framework MCP Server MCP server in PolicyLayer and add a rule for ugf_vault_build_tx: 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 Universal Gas Framework MCP Server. Nothing to install.

What risk level is ugf_vault_build_tx? +

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

Can I rate-limit ugf_vault_build_tx? +

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

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

ugf_vault_build_tx is provided by the Universal Gas Framework MCP Server MCP server (tychiwallet/ugf-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.