tlc_simulate · Tlaplus MCP: Risk & Policy

WHAT IT DOES

What tlc_simulate does on Tlaplus

AI agents invoke tlc_simulate to trigger actions in Tlaplus. 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 tlc_simulate needs a policy

This tool executes code (TLC simulator) against user-provided specifications. While the operation itself is deterministic and read-only in terms of its output (simulation traces), it performs computation that could consume significant resources (CPU, memory, time) depending on the specification complexity and simulation parameters.

From the tool's definition Tool description explicitly states 'Run TLC in simulation mode to randomly explore execution traces' — this invokes the TLC model checker to execute and explore a TLA+ specification, which is an external operation with effects dependent on the specification…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

tlc_simulate Rate-limited

tlc_simulate 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": {
    "tlc_simulate": {
      "limits": [
        {
          "counter": "tlc_simulate_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 Tlaplus, so you can run agents against it safely.

FAQ

Questions about tlc_simulate

What does the tlc_simulate tool do? +

Run TLC in simulation mode to randomly explore execution traces. Faster than exhaustive checking but not complete — useful for large state spaces or quick smoke tests. It is categorised as a Execute tool in the Tlaplus MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on tlc_simulate? +

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

What risk level is tlc_simulate? +

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

Can I rate-limit tlc_simulate? +

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

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

tlc_simulate is provided by the Tlaplus MCP server (richashworth/tlaplus-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.