Compute CAC payback period (months) on gross profit from the user's own numbers and judge it against StackSwap's bands (<12 months SMB/PLG, 18-24 months defensible enterprise). Pass cac OR (salesAndMarketingSpend + newCustomers); plus monthlyRevenuePerCustomer OR annualRevenuePerCustomer; optiona...
AI agents call compute_cac_payback to retrieve information from StackSwap without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
cac | number | — | Fully-loaded customer acquisition cost per customer. |
segment | string | — | Optional segment for a calibrated verdict band. |
newCustomers | number | — | New customers acquired in the period (used with `salesAndMarketingSpend`). |
grossMarginPct | number | — | Gross margin percent (1-100). Defaults to 80 with a warning if omitted. |
salesAndMarketingSpend | number | — | Total S&M spend for the period (used with `newCustomers` to derive CAC). |
annualRevenuePerCustomer | number | — | Annual contract value per new customer (converted to monthly internally). |
monthlyRevenuePerCustomer | number | — | Monthly recurring revenue per new customer. |
Parameters from the server's own tool schema.
This is a pure calculation and benchmarking tool that takes user inputs, performs arithmetic/comparison operations, and returns analytical results. It has no side effects, makes no API calls to fetch external data, does not modify any stored data, and does not execute arbitrary code. It is squarely a Read operation: retrieving insights from user-supplied figures through deterministic computation.
From the tool's definition Tool description states 'Computes on supplied figures only — no data fetch' and 'read-only tools wrapping stackswap.ai'.
Attacks that exploit this kind of access
Compute CAC payback period (months) on gross profit from the user's own numbers and judge it against StackSwap's bands (<12 months SMB/PLG, 18-24 months defensible enterprise). Pass cac OR (salesAndMarketingSpend + newCustomers); plus monthlyRevenuePerCustomer OR annualRevenuePerCustomer; optional grossMarginPct (defaults to 80 with a warning) and segment (smb / mid-market / enterprise) for a calibrated verdict. Returns the payback in months, the verdict, and the retention caveat. Computes on supplied figures only — no data fetch. Use when the user asks 'what's my CAC payback', 'is my payback period healthy', or pastes CAC / revenue numbers. It is categorised as a Read tool in the StackSwap MCP Server, which means it retrieves data without modifying state.
compute_cac_payback accepts 7 parameters: cac, segment, newCustomers, grossMarginPct, salesAndMarketingSpend, annualRevenuePerCustomer, monthlyRevenuePerCustomer. The full parameter table on this page comes from the server's own tool schema.
Register the StackSwap MCP server in PolicyLayer and add a rule for compute_cac_payback: 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 StackSwap. Nothing to install.
compute_cac_payback 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 compute_cac_payback 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 compute_cac_payback. 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.
compute_cac_payback is provided by the StackSwap MCP server (StonesofCreation/stackswap-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.
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