set_account_override_tool · Plaid MCP: Risk & Policy

WHAT IT DOES

What set_account_override_tool does on Plaid

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

WHY IT NEEDS A POLICY

Why set_account_override_tool needs a policy

This tool modifies account data by writing a corrected APR value to a linked card record. While the change is reversible (via the sibling tool clear_account_override_tool), it alters financial metadata that could affect downstream calculations, analysis, or financial decisions. It does not delete data (Destructive), execute arbitrary code (Execute), or move money (Financial), making Write the appropriate category.

From the tool's definition Tool description states it will 'Annotate a linked card' — this modifies stored account metadata with a real APR value. The verb 'annotate' indicates creation or modification of data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_account_override_tool Rate-limited

set_account_override_tool 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_account_override_tool": {
      "limits": [
        {
          "counter": "set_account_override_tool_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 Plaid, so you can run agents against it safely.

FAQ

Questions about set_account_override_tool

What does the set_account_override_tool tool do? +

Annotate a linked card with the real APR when Plaid misses it. It is categorised as a Write tool in the Plaid 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_account_override_tool? +

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

What risk level is set_account_override_tool? +

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

Can I rate-limit set_account_override_tool? +

Yes. Add a rate_limit block to the set_account_override_tool 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_account_override_tool completely? +

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

set_account_override_tool is provided by the Plaid MCP server (t-rhex/plaid-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.