Estimate the output amount for a fee token swap. The Fee AMM uses a fixed rate
AI agents call estimate_fee_swap to retrieve information from Tempo without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a calculation/estimation of swap output amounts without actually executing a swap, modifying balances, or committing any transactions. It is purely informational, similar to a price quote or simulation. Even in the context of a payment/blockchain system, estimation functions that do not execute transactions or alter state are classified as Read operations.
From the tool's definition Tool name 'estimate_fee_swap' and description 'Estimate the output amount for a fee token swap' indicate a read-only query operation that returns calculated values without executing or modifying state.
Documented attack patterns abuse exactly the kind of access estimate_fee_swap gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Tempo, and nothing reaches the server without passing your rules. This is the rule we recommend for estimate_fee_swap:
{
"version": "1",
"default": "deny",
"tools": {
"estimate_fee_swap": {}
}
}estimate_fee_swap is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Estimate the output amount for a fee token swap. The Fee AMM uses a fixed rate. It is categorised as a Read tool in the Tempo MCP Server, which means it retrieves data without modifying state.
Register the Tempo MCP server in PolicyLayer and add a rule for estimate_fee_swap: 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 Tempo. Nothing to install.
estimate_fee_swap 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 estimate_fee_swap 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 estimate_fee_swap. 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.
estimate_fee_swap is provided by the Tempo MCP server (arome3/tempo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Tempo, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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61 Tempo tools catalogued and risk-classified — across an index of 43,000+ MCP servers.