canton_upload_dar · Tenzro Ledger MCP: Risk & Policy

WHAT IT DOES

What canton_upload_dar does on Tenzro Ledger MCP

AI agents use canton_upload_dar 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 canton_upload_dar needs a policy

This tool creates or uploads a DAML Archive package to a participant node, which is a reversible write operation that modifies the ledger infrastructure. It does not delete data (hence not Destructive), does not execute arbitrary code (hence not Execute in the narrow sense), and does not move funds (hence not Financial).

From the tool's definition Tool performs 'Upload a DAR (DAML Archive)' via POST /v2/packages, which is a create/upload operation that modifies the state of the participant by adding new DAML packages.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

canton_upload_dar Rate-limited

canton_upload_dar 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": {
    "canton_upload_dar": {
      "limits": [
        {
          "counter": "canton_upload_dar_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 canton_upload_dar

What does the canton_upload_dar tool do? +

Upload a DAR (DAML Archive) to the participant via POST /v2/packages. 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 canton_upload_dar? +

Register the Tenzro Ledger MCP server in PolicyLayer and add a rule for canton_upload_dar: 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 canton_upload_dar? +

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

Can I rate-limit canton_upload_dar? +

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

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

canton_upload_dar 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.