spawn_agent · Tenzro Ledger MCP: Risk & Policy

WHAT IT DOES

What spawn_agent does on Tenzro Ledger MCP

AI agents invoke spawn_agent to trigger actions in Tenzro Ledger MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why spawn_agent needs a policy

Spawning an agent triggers the creation and execution of an autonomous sub-agent process with delegated identity and role. This is an Execute-category action because it initiates external operations whose effects depend on the arguments (identity, role).

From the tool's definition Spawn a child agent from a parent identity with a specific role

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

spawn_agent Rate-limited

spawn_agent stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "spawn_agent": {
      "limits": [
        {
          "counter": "spawn_agent_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 spawn_agent

What does the spawn_agent tool do? +

Spawn a child agent from a parent identity with a specific role. It is categorised as a Execute tool in the Tenzro Ledger MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on spawn_agent? +

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

spawn_agent is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit spawn_agent? +

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

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

spawn_agent 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.