## Support for Network Blocklists and Allowlists
(`--blocked-url-pattern` & `--allowed-url-pattern` arguments)
This PR adds support for CLI options to restrict network access in the
browser session via URL patterns.
### Key Features & How It Works
- **Pattern Matching:** Utilizes the [URLPattern
Standard](https://urlpattern.spec.whatwg.org/) for pattern matching.
- **Target Detachment:** Silently detaches from targets (pages/tabs)
whose URLs match blocked patterns (or do not match allowed patterns)
upon connection.
- **Runtime Blocking:** Prevents navigations and blocks runtime requests
(such as fetch/XHR and subresources) if they violate the pattern rules.
- **Mutual Exclusivity:** `--blocked-url-pattern` and
`--allowed-url-pattern` conflict with each other and cannot be
configured simultaneously.
- **Browser Requirements:**
- **`--allowed-url-pattern`**: Requires **Chrome 149+**.
- **`--blocked-url-pattern`**: Works on Chrome versions older than 149,
but **Chrome 149+ is highly recommended**.
### Important Limitations & Side Effects
- **Network Emulation/Throttling Conflict:** Network throttling is
disabled when a network blocklist/allowlist is configured, to avoid
conflicting with Puppeteer's underlying blocking mechanisms.
- Using the `emulate` tool to modify `networkConditions` (e.g. setting
to `Offline`) will throw an error: *`Network throttling is not supported
when network blocking (allowlist/blocklist) is configured.`*
- Other emulation settings (e.g., `cpuThrottlingRate`, `geolocation`,
`viewport`) are unaffected and remain fully functional.
---
### Configuration Examples
#### 1. Blocking specific domains or endpoints (Blocklist)
Add the `--blocked-url-pattern` options to the `args` list in your MCP
settings file:
```json
{
"mcpServers": {
"chrome-devtools": {
"command": "npx",
"args": [
"chrome-devtools-mcp@latest",
"--blocked-url-pattern=*://*.blocked-example.com/*",
"--blocked-url-pattern=*://*.another-blocked-example.com/*"
]
}
}
}
```
#### 2. Restricting access to authorized domains (Allowlist)
Add the `--allowed-url-pattern` options to restrict the browser to
permitted hosts (requires Chrome 149+):
```json
{
"mcpServers": {
"chrome-devtools": {
"command": "npx",
"args": [
"chrome-devtools-mcp@latest",
"--allowed-url-pattern=https://*.allowed-example.com/*",
"--allowed-url-pattern=https://*.another-allowed-example.com/*"
]
}
}
}
```
---------
Co-authored-by: Natallia Harshunova <nharshunova@chromium.org>
Co-authored-by: Alex Rudenko <alexrudenko@chromium.org>
Natasha Gorshunova