wait_for_next_error · Pigeon MCP: Risk & Policy

WHAT IT DOES

What wait_for_next_error does on Pigeon

AI agents invoke wait_for_next_error to trigger actions in Pigeon. 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_next_error needs a policy

This tool triggers an external operation (blocking on browser state) whose effects and duration depend on runtime browser conditions. While it does not modify data or execute arbitrary code directly, it performs a control-flow operation (blocking/waiting) that affects system behavior. This fits Execute better than Read because it initiates an active operation rather than passively retrieving already-collected data.

From the tool's definition Tool description states it 'Block[s] until a new browser error arrives' — this invokes runtime blocking behavior on a browser context. The sibling tool eval_in_page confirms this server executes code within a page context.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

wait_for_next_error Rate-limited

wait_for_next_error 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_next_error": {
      "limits": [
        {
          "counter": "wait_for_next_error_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 Pigeon, so you can run agents against it safely.

FAQ

Questions about wait_for_next_error

What does the wait_for_next_error tool do? +

Block until a new browser error arrives or the timeout elapses. Useful for:. It is categorised as a Execute tool in the Pigeon 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_next_error? +

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

What risk level is wait_for_next_error? +

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

Can I rate-limit wait_for_next_error? +

Yes. Add a rate_limit block to the wait_for_next_error 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_next_error completely? +

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

wait_for_next_error is provided by the Pigeon MCP server (pepperonas/pigeon). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.