Emulate device viewport and user agent
Introduced 2026-01-27 · score 0.96
HOW TO USE IT
When checking a page under a mobile or different desktop device configuration, call `emulate` with `viewport` and/or `userAgent`; set either to null to reset its override.
emulate({"viewport": <viewport-value>, "userAgent": <user-agent-string>})WHY THIS HELPS
Check a web page under a mobile or different desktop device configuration.
REQUIREMENTS AND LIMITATIONS
- Version: 0.14.0
- viewport: Viewport override; set to null to reset to the default viewport. Its value format is not specified in this version's docs.
- userAgent: User-agent override; set to null to clear it.
- Both attributes are optional.
- The recommended way is to emulate via the MCP server instead of a parallel DevTools session.
- Docs conflict: Current official docs describe viewport as a formatted string and clearing userAgent with an empty string; the version 0.14.0 docs instead specify unknown value types and null resets. This card follows the 0.14.0 behavior.
FIRST-PARTY EVIDENCE
- https://github.com/ChromeDevTools/chrome-devtools-mcp/releases/tag/chrome-devtools-mcp-v0.14.0
- https://github.com/ChromeDevTools/chrome-devtools-mcp/pull/798
- https://github.com/ChromeDevTools/chrome-devtools-mcp/blob/a8169676f920f88965a2574f53affe15c1278b43/docs/tool-reference.md
Check the installed version and the source before using it. Entry JSON