---
title: "Ask for the fewest permissions the · Agent Wranglers"
url: https://agentwranglers.se/playbook/desktop-apps/browser-extensions/extension-permissions
id: DSK-14
level: Required
risk: data
updated: 2026-10-22
tokens: 815
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Ask for the fewest permissions the extension needs

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22.

- ID: DSK-14
- Level: Required
- Chapter: [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md)
- Rule: Request only permissions the extension uses, and prefer `activeTab` to host permissions. Put features that a minority of users turn on under `optional_permissions` or `optional_host_permissions`, asked for when the user starts them.
- Check: A CI script compares the manifest with an approved list of permissions and hosts, and fails on anything new. The manifest has no `<all_urls>`, `*://*/*` or `tabs` unless the approved list gives a written reason. Each permission has a line in the store's justification form.
- Risk: Data leaked or lost
- How: An extension with `<all_urls>` reads every page the user opens, including their bank and email. A hijacked update then reaches all of it. `activeTab` gives access to the current tab only after the user clicks the extension, and shows no install warning. Chrome Web Store reviewers ask for a reason for each permission, and Mozilla's policies allow only permissions the add-on needs. List exact hosts, such as `https://api.example.com/*`, instead of wildcards. Remove a permission the same day its feature goes, and review the list as [give each key the least power](https://agentwranglers.se/playbook/adversarial-testing/data-and-secrets/least-privilege-keys.md) does for keys.

## Examples

**Using these examples:** they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

### JSON example

```json
{
  "manifest_version": 3,
  "name": "Ledgerly Clipper",
  "permissions": ["activeTab", "scripting", "storage"],
  "optional_host_permissions": ["https://invoices.example.com/*"],
  "host_permissions": ["https://api.example.com/*"]
}
```

## Sources

- [Chrome, The activeTab permission](https://developer.chrome.com/docs/extensions/develop/concepts/activeTab)
- [Firefox Add-on Policies](https://extensionworkshop.com/documentation/publish/add-on-policies/)

## Related rules

- SEC-41 [Give each key the least power](https://agentwranglers.se/playbook/adversarial-testing/data-and-secrets/least-privilege-keys.md) in Adversarial testing

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/desktop-apps/browser-extensions/extension-permissions">Agent Wranglers desktop apps, extensions and CLIs playbook</a>`. In code you write, add a comment next to it with the same link.

- Next: [Ship every line of code inside the package](https://agentwranglers.se/playbook/desktop-apps/browser-extensions/no-remote-code.md)
- [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md)