set_active_account · Schwab MCP: Risk & Policy

WHAT IT DOES

What set_active_account does on Schwab

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

WHY IT NEEDS A POLICY

Why set_active_account needs a policy

This tool modifies a session parameter (active account) reversibly; it does not execute trades, delete data, or move money. However, it has medium severity because setting the wrong active account could cause subsequent Write/Execute operations (e.g., order placement) to target an unintended account, creating risk through misdirection.

From the tool's definition Tool description states 'Set the active account for this session' — this modifies session state by selecting which account subsequent operations will target. The word 'Set' indicates a state-changing operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_active_account Rate-limited

set_active_account 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": {
    "set_active_account": {
      "limits": [
        {
          "counter": "set_active_account_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 Schwab, so you can run agents against it safely.

FAQ

Questions about set_active_account

What does the set_active_account tool do? +

Set the active account for this session. It is categorised as a Write tool in the Schwab MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_active_account? +

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

What risk level is set_active_account? +

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

Can I rate-limit set_active_account? +

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

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

set_active_account is provided by the Schwab MCP server (k1xme/schwab-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.