update_portfolio_weights · Portfolio MCP: Risk & Policy

WHAT IT DOES

What update_portfolio_weights does on Portfolio

AI agents use update_portfolio_weights to create or update resources in Portfolio — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Portfolio environment.

WHY IT NEEDS A POLICY

Why update_portfolio_weights needs a policy

This tool modifies portfolio state (weights/allocations) reversibly. It does not delete data (would be Destructive) or move money (would be Financial), but it changes investment allocations which affects financial outcomes. Classified as Write rather than Execute because it updates a specific data structure (portfolio weights) rather than executing arbitrary code.

From the tool's definition Tool name 'update_portfolio_weights' and server context indicating ability to 'manage investment portfolios' and modify portfolio configurations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_portfolio_weights Rate-limited

update_portfolio_weights stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_portfolio_weights": {
      "limits": [
        {
          "counter": "update_portfolio_weights_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Portfolio, so you can run agents against it safely.

FAQ

Questions about update_portfolio_weights

What does the update_portfolio_weights tool do? +

update_portfolio_weights. It is categorised as a Write tool in the Portfolio MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_portfolio_weights? +

Register the Portfolio MCP server in PolicyLayer and add a rule for update_portfolio_weights: 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 Portfolio. Nothing to install.

What risk level is update_portfolio_weights? +

update_portfolio_weights is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit update_portfolio_weights? +

Yes. Add a rate_limit block to the update_portfolio_weights 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 update_portfolio_weights completely? +

Set action: deny in the PolicyLayer policy for update_portfolio_weights. 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 update_portfolio_weights? +

update_portfolio_weights is provided by the Portfolio MCP server (l4b4r4b4b4/portfolio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.