pool_signal · MidOS - MCP Community Library MCP

WHAT IT DOES

What pool_signal does on MidOS - MCP Community Library

AI agents invoke pool_signal to trigger actions in MidOS - MCP Community Library. 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 pool_signal needs a policy

Signaling an action to a multi-instance coordination pool triggers external operations or state changes across potentially many running agent instances. This is not merely reading data — it actively dispatches or triggers behavior in the coordination system. The blast radius is high because a misused signal could affect multiple coordinated agent instances simultaneously.

From the tool's definition "Signal an action to the multi-instance coordination pool"

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pool_signal Rate-limited

pool_signal 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": {
    "pool_signal": {
      "limits": [
        {
          "counter": "pool_signal_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 MidOS - MCP Community Library, so you can run agents against it safely.

FAQ

Questions about pool_signal

What does the pool_signal tool do? +

Signal an action to the multi-instance coordination pool. It is categorised as a Execute tool in the MidOS - MCP Community Library MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pool_signal? +

Register the MidOS - MCP Community Library MCP server in PolicyLayer and add a rule for pool_signal: 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 MidOS - MCP Community Library. Nothing to install.

What risk level is pool_signal? +

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

Can I rate-limit pool_signal? +

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

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

pool_signal is provided by the MidOS - MCP Community Library MCP server (midos-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.