run_custom_screen

THE RISK

High Risk

Why run_custom_screen needs a policy

The tool name implies execution of custom-defined screening criteria against stock market data. Given the sibling context (technical analysis, backtesting, options setup), this tool likely executes arbitrary or semi-arbitrary screening logic whose effects depend on configuration arguments.

From the tool's definition Tool name 'run_custom_screen' with no description; sibling tools include stock screening, technical analysis, and backtesting on a quantitative trading server. 'run_custom_screen' suggests execution of user-defined screening logic against financial data.

Documented attack patterns abuse exactly the kind of access run_custom_screen gives an agent:

POLICY

How to control run_custom_screen

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 run_custom_screen:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "run_custom_screen": {
      "limits": [
        {
          "counter": "run_custom_screen_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

run_custom_screen 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.

Create a free account and register Momentum — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Momentum tools

Financial find_best_to_sell Auto-find the best puts and calls to SELL. Scans 7-45 DTE across Execute run_stock_screen run_stock_screen Execute sweep_strategy Run a strategy across multiple tickers (max 20). Ranks by Sharpe/return. Execute backtest_strategy Backtest a trading strategy on historical data. 6 presets: Execute walk_forward_test Walk-forward validation: splits data into n folds, detects overfitting. Write log_conviction Log a trade conviction to the journal. Direction: long/short. Write save_strategy Save a custom strategy to disk for re-use. Read analyze_breadth Get a comprehensive market breadth health score (0-100).

All 52 Momentum tools →

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Go deeper

High-risk tools in Momentum → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about run_custom_screen

What does the run_custom_screen tool do? +

run_custom_screen. It is categorised as a Execute tool in the Momentum MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on run_custom_screen? +

Register the Momentum MCP server in PolicyLayer and add a rule for run_custom_screen: 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.

What risk level is run_custom_screen? +

run_custom_screen is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit run_custom_screen? +

Yes. Add a rate_limit block to the run_custom_screen 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.

How do I block run_custom_screen completely? +

Set action: deny in the PolicyLayer policy for run_custom_screen. 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.

What MCP server provides run_custom_screen? +

run_custom_screen 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.

Enforce policy on every Momentum tool call.

Start from Momentum, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →