Get fee update history for a specific chain
AI agents call get_fee_history to retrieve information from UniVoucher MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries fee history data for a blockchain chain. It performs a read-only operation with no side effects, no code execution, no data modification, and no financial transactions. The user can misuse it only by querying sensitive chain information, but the blast radius is minimal since the data is historical and publicly queryable on blockchain networks.
From the tool's definition Tool name is 'get_fee_history' and description states 'Get fee update history for a specific chain' — a retrieval operation that queries historical data without modifying, deleting, or executing transactions.
Attacks that exploit this kind of access
Get fee update history for a specific chain. It is categorised as a Read tool in the UniVoucher MCP Server MCP Server, which means it retrieves data without modifying state.
Register the UniVoucher MCP Server MCP server in PolicyLayer and add a rule for get_fee_history: 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 UniVoucher MCP Server. Nothing to install.
get_fee_history 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 get_fee_history 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 get_fee_history. 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.
get_fee_history is provided by the UniVoucher MCP Server MCP server (univoucher/univoucher-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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