AI agents use tabs_close to create or update resources in OpenChrome — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OpenChrome environment.
An AI agent can call tabs_close faster than any human can review — one bad instruction and it creates or modifies resources in OpenChrome by the hundred, each call as confident as the last.
Documented attack patterns abuse exactly the kind of access tabs_close gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenChrome, and nothing reaches the server without passing your rules. This is the rule we recommend for tabs_close:
{
"version": "1",
"default": "deny",
"tools": {
"tabs_close": {
"limits": [
{
"counter": "tabs_close_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}tabs_close stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Close one or more tabs by tabId, tabIds, or workerId. It is categorised as a Write tool in the OpenChrome MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the OpenChrome MCP server in PolicyLayer and add a rule for tabs_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 OpenChrome. Nothing to install.
tabs_close is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the tabs_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 tabs_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.
tabs_close is provided by the OpenChrome MCP server (shaun0927/openchrome). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 106 OpenChrome tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
106 OpenChrome tools catalogued and risk-classified — across an index of 42,500+ MCP servers.