create_session · Tabby MCP: Risk & Policy

WHAT IT DOES

What create_session does on Tabby

AI agents use create_session to commit financial operations through Tabby — usually the final step of a payment, billing, or trading workflow. A call moves real money.

WHY IT NEEDS A POLICY

Why create_session needs a policy

Creating a checkout session on a BNPL platform is the first step in committing a financial obligation. It sets up the payment arrangement that leads to money movement, placing it firmly in the Financial category. Misuse could result in unauthorized purchase sessions or fraudulent financial commitments.

From the tool's definition Create a Tabby checkout session for BNPL (Buy Now Pay Later) — initiates a financial transaction flow on the Tabby payment platform.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_session Approval-gated

Any call to create_session is blocked until a human approves it. The rest of the server keeps working.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_session": {
      "deny_if": [
        {
          "conditions": [],
          "on_deny": "Requires human approval."
        }
      ]
    }
  }
}

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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 Tabby, so you can run agents against it safely.

FAQ

Questions about create_session

What does the create_session tool do? +

Create a Tabby checkout session for BNPL. It is categorised as a Financial tool in the Tabby MCP Server, which means it involves financial transactions. Block by default and require explicit approval.

How do I enforce a policy on create_session? +

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

What risk level is create_session? +

create_session is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit create_session? +

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

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

create_session is provided by the Tabby MCP server (theyahia/tabby-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.