tvm
Time Value of Money Solver — Solve for any one of PV, FV, PMT, N, or rate given the other four TVM variables.
This record as markdown: /tools/com-wingmanprotocol-agent-gateway/tvm.md
What tvm does on Gateway
AI agents invoke tvm to trigger actions in Gateway. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
| Parameter | Type | Required | Description |
|---|---|---|---|
n | number | — | Number of periods |
fv | number | — | Future value (default 0) |
pv | number | — | Present value |
pmt | number | — | Payment per period |
rate | number | — | Rate per period as a decimal |
solve_for | string | Yes | Which variable to solve for |
Parameters from the server's own tool schema.
Why tvm is rated High
This tool performs a financial calculation (TVM) but does not move money or commit financial obligations — it merely computes a result. It executes a numerical solver algorithm given inputs. No data is stored or deleted, and no real financial transaction occurs.
From the tool's definition Time Value of Money Solver — Solve for any one of PV, FV, PMT, N, or rate given the other four TVM variables.
Attacks that exploit this kind of access
The rule that runs tvm safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Gateway, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For tvm, this is the rule to start with:
tvm stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Gateway, apply this rule, and every tvm call is checked against it from then on.
Questions about tvm
Time Value of Money Solver — Solve for any one of PV, FV, PMT, N, or rate given the other four TVM variables. It is categorised as a Execute tool in the Gateway MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
tvm accepts 6 parameters: n, fv, pv, pmt, rate, solve_for. Required: solve_for. The full parameter table on this page comes from the server's own tool schema.
Register the Gateway MCP server in PolicyLayer and add a rule for tvm: 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 Gateway. Nothing to install.
tvm is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the tvm 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 tvm. 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.
tvm is provided by the Gateway MCP server (https://wingmanprotocol.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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