# browser_close

Close the browser

Agent View of the PolicyLayer registry record for `browser_close`. HTML page: https://policylayer.com/tools/cowork-os/browser-close

## Facts

- Tool: `browser_close`
- Server: CoWork OS (`CoWork-OS/CoWork-OS`) — https://policylayer.com/tools/cowork-os.md
- Homepage: https://github.com/CoWork-OS/CoWork-OS
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "browser_close",
    "arguments": {}
  }
}
```

## Why browser_close is rated High

Closing a browser is an external operation that terminates a running process/session. It is an action with real side effects (ending a browser session, potentially losing unsaved state), making it Execute. It is not purely destructive (no data is permanently deleted), but it does trigger an external operation. Severity is medium because misuse could interrupt active browser sessions or cause loss of unsaved work.

From the tool's own definition: "Close the browser"

## Use case

AI agents invoke browser_close to trigger actions in CoWork OS. 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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches CoWork OS:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_close": {
      "limits": [
        {
          "counter": "browser_close_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on CoWork OS (341)

- `cancel_agent` — Destructive — https://policylayer.com/tools/cowork-os/cancel-agent.md
- `cancel_video_generation_job` — Destructive — https://policylayer.com/tools/cowork-os/cancel-video-generation-job.md
- `cloud_sandbox_delete` — Destructive — https://policylayer.com/tools/cowork-os/cloud-sandbox-delete.md
- `delete_file` — Destructive — https://policylayer.com/tools/cowork-os/delete-file.md
- `disable_macos_launch_agents` — Destructive — https://policylayer.com/tools/cowork-os/disable-macos-launch-agents.md
- `domain_dns_delete` — Destructive — https://policylayer.com/tools/cowork-os/domain-dns-delete.md
- `google-workspace.calendar_event_delete` — Destructive — https://policylayer.com/tools/cowork-os/google-workspace.calendar-event-delete.md
- `google-workspace.slides_delete_slide` — Destructive — https://policylayer.com/tools/cowork-os/google-workspace.slides-delete-slide.md
- `google-workspace.tasks_clear_completed` — Destructive — https://policylayer.com/tools/cowork-os/google-workspace.tasks-clear-completed.md
- `google-workspace.tasks_delete` — Destructive — https://policylayer.com/tools/cowork-os/google-workspace.tasks-delete.md
- `google-workspace.tasks_lists_delete` — Destructive — https://policylayer.com/tools/cowork-os/google-workspace.tasks-lists-delete.md
- `kg_delete_edge` — Destructive — https://policylayer.com/tools/cowork-os/kg-delete-edge.md
- `kg_delete_entity` — Destructive — https://policylayer.com/tools/cowork-os/kg-delete-entity.md
- `skill_delete` — Destructive — https://policylayer.com/tools/cowork-os/skill-delete.md
- `supermemory_forget` — Destructive — https://policylayer.com/tools/cowork-os/supermemory-forget.md
- `blender.render_view` — Execute — https://policylayer.com/tools/cowork-os/blender.render-view.md
- `browser_act_batch` — Execute — https://policylayer.com/tools/cowork-os/browser-act-batch.md
- `browser_attach` — Execute — https://policylayer.com/tools/cowork-os/browser-attach.md
- `browser_back` — Execute — https://policylayer.com/tools/cowork-os/browser-back.md
- `browser_click` — Execute — https://policylayer.com/tools/cowork-os/browser-click.md
- `browser_close_tab` — Execute — https://policylayer.com/tools/cowork-os/browser-close-tab.md
- `browser_drag` — Execute — https://policylayer.com/tools/cowork-os/browser-drag.md
- `browser_emulate` — Execute — https://policylayer.com/tools/cowork-os/browser-emulate.md
- `browser_evaluate` — Execute — https://policylayer.com/tools/cowork-os/browser-evaluate.md
- `browser_fill` — Execute — https://policylayer.com/tools/cowork-os/browser-fill.md
- `browser_forward` — Execute — https://policylayer.com/tools/cowork-os/browser-forward.md
- `browser_handle_dialog` — Execute — https://policylayer.com/tools/cowork-os/browser-handle-dialog.md
- `browser_hover` — Execute — https://policylayer.com/tools/cowork-os/browser-hover.md
- `browser_navigate` — Execute — https://policylayer.com/tools/cowork-os/browser-navigate.md
- `browser_press` — Execute — https://policylayer.com/tools/cowork-os/browser-press.md
- …and 311 more: https://policylayer.com/tools/cowork-os.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=cowork-os · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/cowork-os