Calculate risk-based position size using Fixed Fractional, ATR, or Kelly methods.
AI agents call calculate_position_size to retrieve information from Momentum without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a mathematical calculation to determine position sizing based on risk parameters. It computes and returns a recommended size but does not execute trades, move money, or modify any data. It is purely analytical/read-like in nature, similar to a financial calculator. No financial transactions are initiated.
From the tool's definition Calculate risk-based position size using Fixed Fractional, ATR, or Kelly methods
Documented attack patterns abuse exactly the kind of access calculate_position_size gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Momentum, and nothing reaches the server without passing your rules. This is the rule we recommend for calculate_position_size:
{
"version": "1",
"default": "deny",
"tools": {
"calculate_position_size": {}
}
}calculate_position_size is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Calculate risk-based position size using Fixed Fractional, ATR, or Kelly methods. It is categorised as a Read tool in the Momentum MCP Server, which means it retrieves data without modifying state.
Register the Momentum MCP server in PolicyLayer and add a rule for calculate_position_size: 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 Momentum. Nothing to install.
calculate_position_size 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 calculate_position_size 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 calculate_position_size. 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.
calculate_position_size is provided by the Momentum MCP server (mphinance/momentum-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Momentum, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
52 Momentum tools catalogued and risk-classified — across an index of 43,000+ MCP servers.