AI agents use transfer_erc20_token to commit financial operations through Flow MCP — usually the final step of a payment, billing, or trading workflow. A call moves real money.
This tool commits financial obligations by transferring cryptocurrency tokens. Even though the blockchain may technically allow reversal through a separate transaction, the immediate action is irreversible and moves value. Financial category takes precedence over Destructive or Execute per the severity hierarchy.
From the tool's definition Tool name is 'transfer_erc20_token' and description states 'Transfer an erc20 token to an address' — this directly moves digital assets (ERC-20 tokens) from one address to another, constituting a financial transaction with irreversible consequences.
Attacks that exploit this kind of access
Transfer an erc20 token to an address. You can query the address book to get the recipient address. It is categorised as a Financial tool in the Flow MCP MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Flow MCP server in PolicyLayer and add a rule for transfer_erc20_token: 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 Flow MCP. Nothing to install.
transfer_erc20_token is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the transfer_erc20_token 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.
Set action: deny in the PolicyLayer policy for transfer_erc20_token. 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.
transfer_erc20_token is provided by the Flow MCP server (outblock/flow-mcp-monorepo). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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