close_heapsnapshot

THE RISK

Critical Risk

Why close_heapsnapshot needs a policy

Closing and freeing a heap snapshot is an irreversible operation that discards the in-memory snapshot data. However, the blast radius is low because it only affects a diagnostic/analysis artifact (a memory snapshot), not production data or system state. Severity is low since at worst an analyst loses a snapshot they would need to retake.

From the tool's definition 'Closes a previously loaded memory heapsnapshot, freeing its memory' — the action is irreversible (the snapshot data is freed/discarded)

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

POLICY

How to control close_heapsnapshot

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

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "close_heapsnapshot"
  ]
}

close_heapsnapshot disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

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

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Chrome DevTools tools

Destructive uninstall_extension Uninstalls a Chrome extension by its ID. Destructive close_page Closes the page by its index. The last open page cannot be closed. Execute emulate Emulates various features on the selected page. Execute execute_3p_developer_tool Executes a tool exposed by the page. Execute execute_webmcp_tool Executes a WebMCP tool exposed by the page. Execute lighthouse_audit Get Lighthouse score and reports for accessibility, SEO, best practices, and agentic brows Execute navigate Loads a URL Execute navigate_page Go to a URL, or back, forward, or reload. Use project URL if not specified otherwise.

All 50 Chrome DevTools tools →

Destructive tools on other servers

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Go deeper

Govern database agents → Read-only defaults, blocked table drops, and no DELETE without a WHERE clause on every query.
Critical-risk tools in Chrome DevTools → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-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.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about close_heapsnapshot

What does the close_heapsnapshot tool do? +

Closes a previously loaded memory heapsnapshot, freeing its memory. It is categorised as a Destructive tool in the Chrome DevTools MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on close_heapsnapshot? +

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

What risk level is close_heapsnapshot? +

close_heapsnapshot is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit close_heapsnapshot? +

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

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

close_heapsnapshot is provided by the Chrome DevTools MCP server (ChromeDevTools/chrome-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 Chrome DevTools tool call.

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

CHECK YOUR STACK →