splitwise_create_group · Splitwise MCP Server MCP

WHAT IT DOES

What splitwise_create_group does on Splitwise MCP Server

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

WHY IT NEEDS A POLICY

Why splitwise_create_group needs a policy

This is a Write operation as it creates new data (a group) that is reversible—groups can subsequently be deleted. It is not Read (no query/retrieval), not Execute (does not run arbitrary code/commands), not Destructive (creation is not irreversible), and not Financial (does not move money, though groups manage shared expenses).

From the tool's definition Tool explicitly creates a new group in Splitwise, with capability to add users via email, name, or user_id. The description states 'Create a new group' and specifies user field formats for population.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

splitwise_create_group Rate-limited

splitwise_create_group 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": {
    "splitwise_create_group": {
      "limits": [
        {
          "counter": "splitwise_create_group_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

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

FAQ

Questions about splitwise_create_group

What does the splitwise_create_group tool do? +

Create a new group. Can add users by providing their email/name or user_id. User fields should be in the format users__0__email, users__0__first_name, etc. It is categorised as a Write tool in the Splitwise MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on splitwise_create_group? +

Register the Splitwise MCP Server MCP server in PolicyLayer and add a rule for splitwise_create_group: 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 Splitwise MCP Server. Nothing to install.

What risk level is splitwise_create_group? +

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

Can I rate-limit splitwise_create_group? +

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

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

splitwise_create_group is provided by the Splitwise MCP Server MCP server (svarun115/splitwise-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.