pin_active_tab

Pin active tab (tab id)

SERVERBrowser SOURCEmcp-server-browser

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/browser/pin-active-tab.md

WHAT IT DOES

What pin_active_tab does on Browser

AI agents invoke pin_active_tab to trigger actions in Browser. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why pin_active_tab is rated High

Pinning a browser tab is a browser action that modifies the state of the browser UI (tab pinned state). It triggers an external browser operation. While not destructive or data-modifying, it does change browser state and fits the Execute category (browser action). The blast radius is low as pinning a tab has minimal security or data impact.

From the tool's definition Pin active tab (tab id)

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pin_active_tab safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Browser, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pin_active_tab, this is the rule to start with:

pin_active_tab Rate-limited

pin_active_tab 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.

View as policy code

policy.json

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

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Browser, apply this rule, and every pin_active_tab call is checked against it from then on.

FAQ

Questions about pin_active_tab

What does the pin_active_tab tool do? +

Pin active tab (tab id). It is categorised as a Execute tool in the Browser MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pin_active_tab? +

Register the Browser MCP server in PolicyLayer and add a rule for pin_active_tab: 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 Browser. Nothing to install.

What risk level is pin_active_tab? +

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

Can I rate-limit pin_active_tab? +

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

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

pin_active_tab is provided by the Browser MCP server (mcp-server-browser). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Browser, and thousands of servers like it.

This server

All 19 Browser tools → High-risk tools on this server →

Across the catalogue

All high-risk MCP tools → The MCP Attack Database →

Guides

Govern code and CI agents →Agent sandbox →Least privilege for MCP →