authorize_session · Tenzro Ledger MCP: Risk & Policy

WHAT IT DOES

What authorize_session does on Tenzro Ledger MCP

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

WHY IT NEEDS A POLICY

Why authorize_session needs a policy

The tool issues session keys that authorize automated transactions. While not itself executing transactions (Execute) or moving money (Financial), it creates a reversible credential that enables future operations. The 'high' severity reflects that a compromised session key could enable malicious automated transactions across the wallet/payment system.

From the tool's definition Tool creates a 'time-limited session key for automated transactions' — this modifies security state by issuing a credential that enables subsequent operations, making it a Write action that creates new data/credentials.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

authorize_session Rate-limited

authorize_session 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": {
    "authorize_session": {
      "limits": [
        {
          "counter": "authorize_session_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 Tenzro Ledger MCP, so you can run agents against it safely.

FAQ

Questions about authorize_session

What does the authorize_session tool do? +

Create a time-limited session key for automated transactions. It is categorised as a Write tool in the Tenzro Ledger MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on authorize_session? +

Register the Tenzro Ledger MCP server in PolicyLayer and add a rule for authorize_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 Tenzro Ledger MCP. Nothing to install.

What risk level is authorize_session? +

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

Can I rate-limit authorize_session? +

Yes. Add a rate_limit block to the authorize_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 authorize_session completely? +

Set action: deny in the PolicyLayer policy for authorize_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 authorize_session? +

authorize_session is provided by the Tenzro Ledger MCP server (https://canton-mcp.tenzro.network/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.