wait_for_session · Repl MCP: Risk & Policy

WHAT IT DOES

What wait_for_session does on Repl

AI agents invoke wait_for_session to trigger actions in Repl. 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 wait_for_session needs a policy

wait_for_session triggers real processes with real consequences. An agent gone sideways doesn't fire it once — it starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

wait_for_session Rate-limited

wait_for_session 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": {
    "wait_for_session": {
      "limits": [
        {
          "counter": "wait_for_session_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 Repl, so you can run agents against it safely.

FAQ

Questions about wait_for_session

What does the wait_for_session tool do? +

Wait additional seconds for a session to become ready. Used during LLM-assisted session recovery when more time is needed. It is categorised as a Execute tool in the Repl MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on wait_for_session? +

Register the Repl MCP server in PolicyLayer and add a rule for wait_for_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 Repl. Nothing to install.

What risk level is wait_for_session? +

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

Can I rate-limit wait_for_session? +

Yes. Add a rate_limit block to the wait_for_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 wait_for_session completely? +

Set action: deny in the PolicyLayer policy for wait_for_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 wait_for_session? +

wait_for_session is provided by the Repl MCP server (takafu/repl-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.