Low Risk

format_units

Convert smallest unit value to human-readable format (e.g., wei to ETH)

How to control format_units ↓

What format_units does on Sperax Ecosystem Crypto & DeFI MCP Server

AI agents call format_units to retrieve information from Sperax Ecosystem Crypto & DeFI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

Why format_units needs a policy

This is a utility function that performs numeric formatting and unit conversion. It takes an input value and returns a formatted representation without creating, modifying, deleting, executing commands, or moving funds. It is a read-only, stateless operation with minimal security risk.

From the tool's definition The tool description states it 'Convert[s] smallest unit value to human-readable format (e.g., wei to ETH)' — a pure transformation/formatting operation with no side effects, data modification, or external state changes.

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

How to control format_units

PolicyLayer is an MCP gateway — it sits between your AI agents and Sperax Ecosystem Crypto & DeFI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for format_units:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "format_units": {}
  }
}

format_units is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

  1. Create a free account and register Sperax Ecosystem Crypto & DeFI MCP Server — 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.
CAP THIS TOOL →

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Related tools and policies

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Questions about format_units

What does the format_units tool do? +

Convert smallest unit value to human-readable format (e.g., wei to ETH). It is categorised as a Read tool in the Sperax Ecosystem Crypto & DeFI MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on format_units? +

Register the Sperax Ecosystem Crypto & DeFI MCP Server MCP server in PolicyLayer and add a rule for format_units: 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 Sperax Ecosystem Crypto & DeFI MCP Server. Nothing to install.

What risk level is format_units? +

format_units is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit format_units? +

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

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

format_units is provided by the Sperax Ecosystem Crypto & DeFI MCP Server MCP server (sperax/sperax-crypto-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Sperax Ecosystem Crypto & DeFI MCP Server tool call.

Start from Sperax Ecosystem Crypto & DeFI MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

1318 Sperax Ecosystem Crypto & DeFI MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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