break_on_xhr

THE RISK

High Risk

Setting an XHR breakpoint is an active operation that modifies the runtime debugging state of a running process. It intercepts and pauses execution when matching network requests are made, which constitutes triggering external operations/affecting execution flow rather than merely reading data.

From the tool's definition 'Sets a breakpoint that triggers when an XHR/Fetch request URL contains the specified string' — this actively configures debugging state in the Chrome DevTools Protocol runtime, affecting program execution flow

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

HOW TO CONTROL BREAK_ON_XHR

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

policy.json

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

break_on_xhr 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 MiniApp CDP 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

More MiniApp CDP MCP tools

Destructive remove_breakpoints remove_breakpoints Execute evaluate_script Evaluates a JavaScript expression in the current context. If execution is paused, it autom Execute step Controls execution when paused. action must be one of: Execute resume_execution resume_execution Execute set_breakpoint_on_text Finds a text string in all loaded scripts and sets a breakpoint at that location. Execute switch_target Switches the CDP connection to a different target thread (e.g. from WebView to AppService) Write save_script_source Saves the full source code of a JavaScript script to a local file. Read get_paused_info Gets information about the current paused state including call stack, current location, an

All 18 MiniApp CDP MCP tools →

Execute tools on other servers

Frida Game Hacking MCP remove_breakpoint Procmon request_elevation WireMCP capture_packets Pentest Ai run_probe

Go deeper

High-risk tools in MiniApp CDP 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.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the break_on_xhr tool do? +

Sets a breakpoint that triggers when an XHR/Fetch request URL contains the specified string. It is categorised as a Execute tool in the MiniApp CDP 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 break_on_xhr? +

Register the MiniApp CDP MCP server in PolicyLayer and add a rule for break_on_xhr: 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 MiniApp CDP MCP. Nothing to install.

What risk level is break_on_xhr? +

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

Can I rate-limit break_on_xhr? +

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

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

break_on_xhr is provided by the MiniApp CDP MCP server (zhizhuodemao/miniapp-cdp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MiniApp CDP MCP tool call.

Deterministic rules across all 18 MiniApp CDP MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

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Free to start. No card required.

18 MiniApp CDP MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

// WHAT BREAK_ON_XHR ON MINIAPP CDP MCP DOES

// THE RISK

// HOW TO CONTROL BREAK_ON_XHR

// EXPLORE