set_xhr_breakpoint

THE RISK

High Risk

Why set_xhr_breakpoint needs a policy

This tool modifies debugger state by setting a breakpoint that actively interrupts JavaScript execution when matching network requests occur. It triggers an external operation (pausing execution) whose effect depends on the URL pattern argument. This is an Execute-category action as it controls program execution flow in the browser debugger.

From the tool's definition Set an XHR/Fetch breakpoint that pauses execution when a request URL contains the specified substring

Documented attack patterns abuse exactly the kind of access set_xhr_breakpoint gives an agent:

POLICY

How to control set_xhr_breakpoint

PolicyLayer is an MCP gateway — it sits between your AI agents and ReverseCraft DevTools MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for set_xhr_breakpoint:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_xhr_breakpoint": {
      "limits": [
        {
          "counter": "set_xhr_breakpoint_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

set_xhr_breakpoint 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.

Create a free account and register ReverseCraft DevTools MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More ReverseCraft DevTools MCP tools

Destructive clear_cookies Clear browser cookies for all sites or a specific domain. Destructive clear_persistent_scripts Remove all registered persistent scripts for the current page at once. This is useful for Destructive clear_script_replacements Remove all script replacement rules for the current page. Destructive remove_persistent_script Remove a previously registered persistent script by its identifier. After removal, the sc Destructive remove_script_replacement Remove a script replacement rule by its ID. Destructive remove_xhr_breakpoint Remove a previously set XHR/Fetch breakpoint by its URL pattern, or remove all XHR breakpo Destructive close_page Closes the page by its index. The last open page cannot be closed. Execute navigate_page Navigates the currently selected page to a URL.

All 46 ReverseCraft DevTools MCP tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

High-risk tools in ReverseCraft DevTools MCP → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about set_xhr_breakpoint

What does the set_xhr_breakpoint tool do? +

Set an XHR/Fetch breakpoint that pauses execution when a request URL contains the specified substring. It is categorised as a Execute tool in the ReverseCraft DevTools MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on set_xhr_breakpoint? +

Register the ReverseCraft DevTools MCP server in PolicyLayer and add a rule for set_xhr_breakpoint: 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 ReverseCraft DevTools MCP. Nothing to install.

What risk level is set_xhr_breakpoint? +

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

Can I rate-limit set_xhr_breakpoint? +

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

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

set_xhr_breakpoint is provided by the ReverseCraft DevTools MCP server (reverse-craft/rc-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every ReverseCraft DevTools MCP tool call.

Start from ReverseCraft DevTools MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →