handle_signal · Rr MCP: Risk & Policy

WHAT IT DOES

What handle_signal does on Rr

AI agents invoke handle_signal to trigger actions in Rr. 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 handle_signal needs a policy

This tool configures signal handling behavior in a GDB debugging session, which triggers external operations affecting how signals are processed and dispatched to the debugged program. It modifies the execution behavior of the debug session rather than simply reading state, and incorrect configuration could cause the debugged process to crash or behave unexpectedly.

From the tool's definition Configure how GDB handles a specific signal (stop, pass to program, print)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

handle_signal Rate-limited

handle_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": {
    "handle_signal": {
      "limits": [
        {
          "counter": "handle_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 Rr, so you can run agents against it safely.

FAQ

Questions about handle_signal

What does the handle_signal tool do? +

Configure how GDB handles a specific signal (stop, pass to program, print). It is categorised as a Execute tool in the Rr MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on handle_signal? +

Register the Rr MCP server in PolicyLayer and add a rule for handle_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 Rr. Nothing to install.

What risk level is handle_signal? +

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

Can I rate-limit handle_signal? +

Yes. Add a rate_limit block to the handle_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 handle_signal completely? +

Set action: deny in the PolicyLayer policy for handle_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 handle_signal? +

handle_signal is provided by the Rr MCP server (jnjaeschke/rr-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.