Revokes an ERC20 token allowance for a specific spender on a specified chain
AI agents call revokeAllowance to permanently remove resources in Token Revoke — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Revoking a token allowance is an irreversible blockchain transaction that permanently removes authorization for a spender to transfer tokens on behalf of the owner. While not directly moving funds, it irreversibly modifies critical financial permissions and falls under Destructive rather than Execute because revocation is a one-way operation with permanent state change effects.
From the tool's definition Tool name 'revokeAllowance' and description 'Revokes an ERC20 token allowance' indicate irreversible removal of a blockchain permission.
Attacks that exploit this kind of access
Revokes an ERC20 token allowance for a specific spender on a specified chain. It is categorised as a Destructive tool in the Token Revoke MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Token Revoke MCP server in PolicyLayer and add a rule for revokeAllowance: 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 Token Revoke. Nothing to install.
revokeAllowance is a Destructive 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 revokeAllowance 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 revokeAllowance. 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.
revokeAllowance is provided by the Token Revoke MCP server (kukapay/token-revoke-mcp). 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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