browser_close
A destructive tool on the Looking Glass MCP server.
This record as markdown: /tools/io-github-sahib-sawhney-wh-looking-glass-mcp/browser-close.md
What browser_close does on Looking Glass
AI agents call browser_close to permanently remove resources in Looking Glass, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
| Parameter | Type | Required | Description |
|---|---|---|---|
tabId | string | — | Tab ID to close (defaults to active tab) |
Parameters from the server's own tool schema.
Why browser_close is rated Critical
Based on name alone (description is empty), 'browser_close' likely terminates a browser session. This is potentially irreversible as session state, open tabs, and unsaved data may be lost. Confidence is reduced due to empty description.
From the tool's definition Tool name 'browser_close' with empty description. Closing a browser session may irreversibly terminate session state, active connections, and unsaved data.
Attacks that exploit this kind of access
The rule that runs browser_close safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Looking Glass, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For browser_close, this is the rule to start with:
browser_close is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect Looking Glass, apply this rule, and every browser_close call is checked against it from then on.
Questions about browser_close
browser_close is a destructive tool on the Looking Glass MCP server. It is categorised as a Destructive tool in the Looking Glass MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
browser_close accepts 1 parameter: tabId. The full parameter table on this page comes from the server's own tool schema.
Register the Looking Glass MCP server in PolicyLayer and add a rule for browser_close: 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 Looking Glass. Nothing to install.
browser_close is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the browser_close 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.
Set action: deny in the PolicyLayer policy for browser_close. 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.
browser_close is provided by the Looking Glass MCP server (looking-glass-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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