GTM API / Check custom proxy

Probe a customer-supplied proxy tuple and report the exit it reaches: country, IP and round-trip latency. Nothing is written: call it for a proxy you are about to pass as custom_proxy_config, on create or on update-proxy. A proxy that refuses is a SUCCESSFUL call with ok:false plus error_kind (timeout | tls | network | http_error); only a malformed tuple is a 422. The write paths run the same probe themselves, so this verb is for showing the operator what a tuple resolves to BEFORE committing to it. Checking an edit of a browser that already rides its own proxy? Pass its sid and leave the password out: the stored one is probed, as update-proxy keeps it, for the same ip and username only. Contract: - MCP tool check_antidetect_browser_proxy, registry package mcp.linkedin/antidetect_browsers, mount linkedin.browsers. - Operation action, response envelope action. - Flags: read only.