Check whether a (owner, nonce) slot has been consumed.
AI agents call permit2_nonce_used to retrieve information from Tenzro Ledger MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a simple lookup/query operation on nonce state to verify whether a permit has been used. It retrieves information (nonce consumption status) with no side effects, no code execution, no data modification, and no financial impact. It is defensive in nature—useful for validating permit validity before processing. This is characteristic of Read category operations.
From the tool's definition Tool description states 'Check whether a (owner, nonce) slot has been consumed' - a purely read operation that queries state without modifying or executing anything.
Attacks that exploit this kind of access
Check whether a (owner, nonce) slot has been consumed. It is categorised as a Read tool in the Tenzro Ledger MCP MCP Server, which means it retrieves data without modifying state.
Register the Tenzro Ledger MCP server in PolicyLayer and add a rule for permit2_nonce_used: 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 Tenzro Ledger MCP. Nothing to install.
permit2_nonce_used is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the permit2_nonce_used 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 permit2_nonce_used. 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.
permit2_nonce_used is provided by the Tenzro Ledger MCP server (https://canton-mcp.tenzro.network/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.
Teams ship this data inside their own products. See what a licence covers →